View Filing Data

Print Document View Excel Document

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2011	Feb. 23, 2012	Jun. 30, 2011
Entity Registrant Name	BRANDYWINE REALTY TRUST
Entity Central Index Key	0000790816
Document Type	10-K
Document Period End Date	Dec. 31, 2011
Amendment Flag	false
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 1,550,583,606
Entity Common Stock, Shares Outstanding		142,728,273
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Entity Registrant Name	BRANDYWINE OPERATING PARTNERSHIP, L.P.
Entity Central Index Key	0001060386
Document Type	10-K
Document Period End Date	Dec. 31, 2011
Amendment Flag	false
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2011	Dec. 31, 2010
Real estate investments:
Rental properties	$ 4,793,080	$ 4,834,111
Accumulated depreciation	(865,710)	(776,078)
Operating real estate investments, net	3,927,370	4,058,033
Construction-in-progress	25,083	33,322
Land inventory	109,008	110,055
Total real estate investments, net	4,061,461	4,201,410
Cash and cash equivalents	410	16,565
Accounts receivable, net	14,718	16,009
Accrued rent receivable, net	108,101	95,541
Investment in real estate ventures, at equity	115,807	84,372
Deferred costs, net	115,362	106,117
Intangible assets, net	70,515	97,462
Notes receivable	18,186	18,205
Other assets	53,158	54,697
Total assets	4,557,718	4,690,378
LIABILITIES AND BENEFICIARIES' EQUITY
Mortgage notes payable	511,061	711,789
Unsecured credit facility	275,500	183,000
Unsecured term loan	37,500	183,000
Unsecured senior notes, net of discounts	1,569,934	1,352,657
Accounts payable and accrued expenses	69,929	72,235
Distributions payable	23,895	22,623
Deferred income, gains and rent	99,569	121,552
Acquired lease intangibles, net	35,106	29,233
Other liabilities	45,528	36,515
Total liabilities	2,668,022	2,712,604
Commitments and contingencies (Note 20)
Brandywine Realty Trust's equity:
Common Shares of Brandywine Realty Trust’s beneficial interest, $0.01 par value; shares authorized 200,000,000; 142,690,755 and 134,601,796 issued in 2011 and 2010, respectively and 142,690,755 and 134,485,117 outstanding in 2011 and 2010, respectively	1,424	1,343
Additional paid-in capital	2,776,197	2,671,217
Deferred compensation payable in common stock	5,631	5,774
Common shares in treasury, at cost, 116,679 in 2010		(3,074)
Common shares in grantor trust, 292,646 in 2011 and 291,281 in 2010	(5,631)	(5,774)
Cumulative earnings	477,338	483,439
Accumulated other comprehensive loss	(6,079)	(1,945)
Cumulative distributions	(1,392,332)	(1,301,521)
Total Brandywine Realty Trust's equity	1,856,591	1,849,502
Non-controlling interests	33,105	128,272
Total equity	1,889,696	1,977,774
Total liabilities and equity	4,557,718	4,690,378
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Real estate investments:
Rental properties	4,793,080	4,834,111
Accumulated depreciation	(865,710)	(776,078)
Operating real estate investments, net	3,927,370	4,058,033
Construction-in-progress	25,083	33,322
Land inventory	109,008	110,055
Total real estate investments, net	4,061,461	4,201,410
Cash and cash equivalents	410	16,565
Accounts receivable, net	14,718	16,009
Accrued rent receivable, net	108,101	95,541
Investment in real estate ventures, at equity	115,807	84,372
Deferred costs, net	115,362	106,117
Intangible assets, net	70,515	97,462
Notes receivable	18,186	18,205
Other assets	53,158	54,697
Total assets	4,557,718	4,690,378
LIABILITIES AND BENEFICIARIES' EQUITY
Mortgage notes payable	511,061	711,789
Unsecured credit facility	275,500	183,000
Unsecured term loan	37,500	183,000
Unsecured senior notes, net of discounts	1,569,934	1,352,657
Accounts payable and accrued expenses	69,929	72,235
Distributions payable	23,895	22,623
Deferred income, gains and rent	99,569	121,552
Acquired lease intangibles, net	35,106	29,233
Other liabilities	45,528	36,515
Total liabilities	2,668,022	2,712,604
Commitments and contingencies (Note 20)
Redeemable limited partnership units at redemption value;
Redeemable limited partnership units at redemption value; 2,698,648 and 9,902,752 issued and outstanding in 2011 and 2010, respectively	38,370	132,855
Brandywine Realty Trust's equity:
General Partnership Capital, 142,690,755 and 134,601,796 units issued in 2011 and 2010, respectively and 142,690,755 and 134,485,117 units outstanding in 2011 and 2010, respectively	1,754,302	1,743,549
Accumulated other comprehensive loss	(6,426)	(2,080)
Total Brandywine Realty Trust's equity	1,851,326	1,844,919
Total liabilities and equity	4,557,718	4,690,378
7.50% Series D Preferred Shares \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Brandywine Realty Trust's equity:
Preferred Shares	47,912	47,912
7.50% Series C Preferred Shares
Brandywine Realty Trust's equity:
Preferred Shares	20	20
7.375% Series D Preferred Shares
Brandywine Realty Trust's equity:
Preferred Shares	23	23
Total equity	43	43
7.375% Series D Preferred Shares \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Brandywine Realty Trust's equity:
Total equity	47,912	47,912
7.375% Series E Preferred Shares \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Brandywine Realty Trust's equity:
Preferred Shares	55,538	55,538
Total equity	$ 55,538	$ 55,538

Consolidated Balance Sheets (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Brandywine Realty Trust's equity:
Preferred shares, shares authorized	20,000,000	20,000,000
Common shares of Brandywine Realty Trust's beneficial interest, par value	$ 0.01	$ 0.01
Common shares of Brandywine Realty Trust's beneficial interest, shares authorized	200,000,000	200,000,000
Common shares of Brandywine Realty Trust's beneficial interest, shares issued	142,690,755	134,601,796
Common shares of Brandywine Realty Trust's beneficial interest, shares outstanding	142,690,755	134,485,117
Common shares in treasury, at cost, shares	0	116,679
Common shares in grantor trust, shares	292,646	291,281
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Brandywine Realty Trust's equity:
Redeemable Limited Partnership, units issued	2,698,648	9,902,752
Redeemable Limited Partnership, units outstanding	2,698,648	9,902,752
General Partners' Capital account, units issued	142,690,755	134,601,796
General Partners' Capital account, units outstanding	142,690,755	134,485,117
7.50% Series C Preferred Shares
Brandywine Realty Trust's equity:
Preferred shares, dividend rate	7.50%	7.50%
Preferred shares, par value	$ 0.01	$ 0.01
Preferred shares, shares issued	2,000,000	2,000,000
Preferred shares, shares outstanding	2,000,000	2,000,000
7.375% Series D Preferred Shares
Brandywine Realty Trust's equity:
Preferred shares, dividend rate	7.375%	7.375%
Preferred shares, par value	$ 0.01	$ 0.01
Preferred shares, shares issued	2,300,000	2,300,000
Preferred shares, shares outstanding	2,300,000	2,300,000
7.50% Series D Preferred Shares \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Brandywine Realty Trust's equity:
Preferred shares, dividend rate	7.50%	7.50%
Preferred shares, shares issued	2,000,000	2,000,000
Preferred shares, shares outstanding	2,000,000	2,000,000
7.375% Series E Preferred Shares \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Brandywine Realty Trust's equity:
Preferred shares, dividend rate	7.375%	7.375%
Preferred shares, shares issued	2,300,000	2,300,000
Preferred shares, shares outstanding	2,300,000	2,300,000

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Revenue:
Rents	$ 480,600	$ 461,101	$ 467,188
Tenant reimbursements	81,236	77,139	76,652
Termination fees	2,993	5,576	3,601
Third party management fees, labor reimbursement and leasing	11,536	11,830	17,151
Other	5,440	4,310	3,328
Total revenue	581,805	559,956	567,920
Operating Expenses:
Property operating expenses	171,991	167,911	162,940
Real estate taxes	56,230	53,564	56,224
Third party management expenses	5,590	5,866	7,996
Depreciation and amortization	217,680	210,592	203,572
General and administrative expenses	24,602	23,306	20,821
Total operating expenses	476,093	461,239	451,553
Operating income	105,712	98,717	116,367
Other Income (Expense):
Interest income	1,813	3,222	2,499
Historic tax credit transaction income	12,026	0	0
Interest expense	(131,405)	(132,640)	(135,740)
Interest expense - amortization of deferred financing costs	(4,991)	(3,770)	(5,864)
Recognized hedge activity	0	0	(916)
Equity in income of real estate ventures	3,775	5,305	4,069
Net gain on sale of interests in real estate	2,791	0	(3)
Net gain on sale of undepreciated real estate	45	0	0
Loss on real estate venture formation	(222)	0	0
(Loss) gain on early extinguishment of debt	(2,776)	(2,110)	23,176
Income (loss) from continuing operations	(13,232)	(31,276)	3,588
Discontinued operations:
Income from discontinued operations	1,253	2,659	6,960
Net (loss) gain on disposition of discontinued operations	7,264	11,011	1,241
Provision for impairment	0	0	(3,700)
Total discontinued operations	8,517	13,670	4,501
Net income (loss)	(4,715)	(17,606)	8,089
Net (income) loss from discontinued operations attributable to non-controlling interests - LP units	(332)	(288)	(91)
Net income attributable to non-controlling interests — partners’ share of consolidated real estate ventures	0	0	(30)
Net (income) loss attributable to non-controlling interests - LP units	548	820	58
Net (income) loss attributable to non-controlling interests	216	532	(63)
Net income (loss) attributable to Brandywine Realty Trust	(4,499)	(17,074)	8,026
Distribution to Preferred Shares	(7,992)	(7,992)	(7,992)
Amount allocated to unvested restricted shareholders	(505)	(512)	(279)
Net loss attributable to Common Shareholders of Brandywine Realty Trust	$ (12,996)	$ (25,578)	$ (245)
Basic earnings (loss) per Common Share:
Continuing operations	$ (0.16)	$ (0.29)	$ (0.04)
Discontinued operations	0.06	0.10	0.04
Basic loss per Common Share	(0.10)	(0.19)	0.00
Diluted earnings (loss) per Common Share:
Continuing operations	(0.16)	(0.29)	(0.04)
Discontinued operations	0.06	0.10	0.04
Diluted loss per Common Share	$ (0.10)	$ (0.19)	$ 0.00
Basic weighted average shares outstanding	135,444,424	131,743,275	111,898,045
Diluted weighted average shares outstanding	135,444,424	131,743,275	113,251,291
Net income (loss) attributable to Brandywine Realty Trust
Income (loss) from continuing operations	$ (12,684)	$ (30,456)	$ 3,616
Income (loss) from discontinued operations	8,185	13,382	4,410
Net income (loss)	(4,499)	(17,074)	8,026
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue:
Rents	480,600	461,101	467,188
Tenant reimbursements	81,236	77,139	76,652
Termination fees	2,993	5,576	3,601
Third party management fees, labor reimbursement and leasing	11,536	11,830	17,151
Other	5,440	4,310	3,328
Total revenue	581,805	559,956	567,920
Operating Expenses:
Property operating expenses	171,991	167,911	162,940
Real estate taxes	56,230	53,564	56,224
Third party management expenses	5,590	5,866	7,996
Depreciation and amortization	217,680	210,592	203,572
General and administrative expenses	24,602	23,306	20,821
Total operating expenses	476,093	461,239	451,553
Operating income	105,712	98,717	116,367
Other Income (Expense):
Interest income	1,813	3,222	2,499
Historic tax credit transaction income	12,026	0	0
Interest expense	(131,405)	(132,640)	(135,740)
Interest expense - amortization of deferred financing costs	(4,991)	(3,770)	(5,864)
Recognized hedge activity	0	0	(916)
Equity in income of real estate ventures	3,775	5,305	4,069
Net gain on sale of interests in real estate	2,791	0	(3)
Net gain on sale of undepreciated real estate	45	0	0
Loss on real estate venture formation	(222)	0	0
(Loss) gain on early extinguishment of debt	(2,776)	(2,110)	23,176
Income (loss) from continuing operations	(13,232)	(31,276)	3,588
Discontinued operations:
Income from discontinued operations	1,253	2,659	6,960
Net (loss) gain on disposition of discontinued operations	7,264	11,011	1,241
Provision for impairment	0	0	(3,700)
Total discontinued operations	8,517	13,670	4,501
Net income (loss)	(4,715)	(17,606)	8,089
Net (income) loss attributable to non-controlling interests	0	0	(30)
Net income (loss) attributable to Brandywine Realty Trust	(4,715)	(17,606)	8,059
Distribution to Preferred Shares	(7,992)	(7,992)	(7,992)
Amount allocated to unvested restricted shareholders	(505)	(512)	(279)
Net loss attributable to Common Shareholders of Brandywine Realty Trust	$ (13,212)	$ (26,110)	$ (212)
Basic earnings (loss) per Common Share:
Continuing operations	$ (0.15)	$ (0.29)	$ (0.04)
Discontinued operations	0.06	0.10	0.04
Basic loss per Common Share	(0.09)	(0.19)	0.00
Diluted earnings (loss) per Common Share:
Continuing operations	(0.15)	(0.29)	(0.04)
Discontinued operations	0.06	0.10	0.04
Diluted loss per Common Share	$ (0.09)	$ (0.19)	$ 0.00
Basic weighted average shares outstanding	145,118,841	137,454,796	114,712,869
Diluted weighted average shares outstanding	145,118,841	137,454,796	116,066,115
Net income (loss) attributable to Brandywine Realty Trust
Income (loss) from continuing operations	$ (13,232)	$ (31,276)	$ 3,558
Income (loss) from discontinued operations	8,517	13,670	4,501
Net income (loss)	$ (4,715)	$ (17,606)	$ 8,059

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net income (loss)	$ (4,715)	$ (17,606)	$ 8,089
Comprehensive income:
Unrealized gain (loss) on derivative financial instruments	(4,499)	7,320	7,395
Ineffectiveness of the hedges	0	0	(125)
Reclassification of realized (gains)/losses on derivative financial instruments to operations, net	153	28	(184)
Total comprehensive income (loss)	(4,346)	7,348	7,086
Comprehensive income (loss)	(9,061)	(10,258)	15,175
Comprehensive (income) loss attributable to non-controlling interest	427	377	(63)
Comprehensive income (loss) attributable to Brandywine Realty Trust	(8,634)	(9,881)	15,112
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Net income (loss)	(4,715)	(17,606)	8,089
Comprehensive income:
Unrealized gain (loss) on derivative financial instruments	(4,499)	7,320	7,395
Ineffectiveness of the hedges	0	0	(125)
Reclassification of realized (gains)/losses on derivative financial instruments to operations, net	153	28	(184)
Total comprehensive income (loss)	(4,346)	7,348	7,086
Comprehensive income (loss)	(9,061)	(10,258)	15,175
Comprehensive (income) loss attributable to non-controlling interest	0	0	(30)
Comprehensive income (loss) attributable to Brandywine Realty Trust	$ (9,061)	$ (10,258)	$ 15,145

Consolidated Statements of Beneficiaries' Equity - USD ($) $ in Thousands	Total	7.375% Series D Preferred Shares	Common Stock	Treasury Stock	Deferred Compensation Payable in Common Stock	Common Shares in Grantor Trust	Additional Paid-in Capital	Cumulative Earnings	Accumulated Other Comprehensive Income (Loss)	Cumulative Distributions	Non-Controlling Interests
Beginning Balance at Dec. 31, 2008	$ 1,722,498	$ 43	$ 882	$ (14,121)	$ 6,274	$ (6,274)	$ 2,351,428	$ 498,716	$ (17,005)	$ (1,150,406)	$ 52,961
Beginning Balance, shares at Dec. 31, 2008		4,300,000	88,610,053	451,116	215,742
Net income (loss)	8,089							8,026			63
Comprehensive income	7,086								7,376		(290)
Issuance of Common Shares of Beneficial Interest	242,323		$ 403				241,920
Issuance of Common Shares of Beneficial Interest, shares			40,250,000
Bonus Share Issuance	123			$ 1,228				(1,105)
Bonus Share Issuance, shares				(36,826)
Vesting of Restricted Stock	(212)		$ 2	$ 2,960	$ 56	(56)	(852)	(2,322)
Vesting of Restricted Stock, shares				(86,172)	(8,971)
Restricted Stock Amortization	3,286						3,286
Restricted Performance Units Amortization	288						288
Conversion of LP Units to Common Shares	0			$ 432				(178)			(254)
Conversion of LP Units to Common Shares, shares				(7,513)
Share Issuance from/to Deferred Compensation Plan	131			$ 1,830	$ (816)	816	(29)	(1,670)
Share Issuance from/to Deferred Compensation Plan, shares			(3,796)	(54,854)	26,092
Share Choice Plan Issuance Shares			(7,081)
Share Choice Plan Issuance	(46)		$ (1)				(45)
Stock Option Amortization	602						602
Outperformance Plan Amortization	927						927
Trustee Fees Paid in Shares	152			$ 466	$ 35	(35)		(314)
Trustee Fees Paid in Shares, shares				(13,987)	(4,895)
Other — consolidated real estate ventures	34										34
Other Activity	678						187		491
Adjustment to Non-controlling Interest	0						12,709	231			(12,940)
Preferred Share distributions	(7,992)									(7,992)
Distributions declared ($0.60), ($0.60), and ($0.45) per share in 2011, 2010 and 2009, respectively	(56,227)									(54,961)	(1,266)
Ending Balance at Dec. 31, 2009	1,921,740	$ 43	$ 1,286	$ (7,205)	$ 5,549	(5,549)	2,610,421	501,384	(9,138)	(1,213,359)	38,308
Ending Balance, shares at Dec. 31, 2009		4,300,000	128,849,176	251,764	255,700
Net income (loss)	(17,606)							(17,074)			(532)
Comprehensive income	7,348								7,193		155
Issuance of Common Shares of Beneficial Interest	71,981		$ 57				71,924
Issuance of Common Shares of Beneficial Interest, shares			5,742,268
Equity issuance costs	(1,214)						(1,214)
Noncontrolling Interest, Increase from Equity Issuance or Sale of Parent Equity Interest	77,732										77,732
Bonus Share Issuance	369			$ 871	$ 369	(369)		(502)
Bonus Share Issuance, shares				(32,607)	(32,607)
Vesting of Restricted Stock	(227)			$ 2,304	$ 103	(103)	(1,114)	(1,417)
Vesting of Restricted Stock, shares				(76,598)	(8,989)
Restricted Stock Amortization	3,483						3,483
Restricted Performance Units Amortization	965						965
Conversion of LP Units to Common Shares				$ 732				(266)			(466)
Conversion of LP Units to Common Shares, shares				(17,468)
Share Issuance from/to Deferred Compensation Plan	0				$ (282)	282
Share Issuance from/to Deferred Compensation Plan, shares			(2,409)		(9,035)
Stock Option Amortization	1,131						1,131
Outperformance Plan Amortization	380						380
Trustee Fees Paid in Shares	99			$ 224	$ 35	(35)		(125)
Trustee Fees Paid in Shares, shares				(8,412)	(3,020)
Exercise of Stock Options	37						37
Exercise of Stock Options, shares			12,761
Adjustment to Non-controlling Interest	0						(14,796)				14,796
Cumulative effect of accounting change for variable interest entities	1,401							1,439			(38)
Preferred Share distributions	(7,992)									(7,992)
Distributions declared ($0.60), ($0.60), and ($0.45) per share in 2011, 2010 and 2009, respectively	(81,853)									(80,170)	(1,683)
Ending Balance at Dec. 31, 2010	1,977,774	$ 43	$ 1,343	$ (3,074)	$ 5,774	(5,774)	2,671,217	483,439	(1,945)	(1,301,521)	128,272
Ending Balance, shares at Dec. 31, 2010		4,300,000	134,601,796	116,679	291,281
Net income (loss)	(4,715)							(4,500)			(215)
Comprehensive income	(4,346)								(4,134)		(212)
Issuance of Common Shares of Beneficial Interest	$ 8,272		$ 7				8,265
Issuance of Common Shares of Beneficial Interest, shares	679,285		679,285
Equity issuance costs	$ (377)						(345)				(32)
Bonus Share Issuance	6			$ 12	$ 6	(6)		(6)
Bonus Share Issuance, shares				(463)	(463)
Vesting of Restricted Stock	(350)		$ 1	$ 3,062			(1,818)	(1,595)
Vesting of Restricted Stock, shares			(85,248)	(116,216)	(9,043)
Restricted Stock Amortization	2,937						2,937
Restricted Performance Units Amortization	1,679						1,679
Conversion of LP Units to Common Shares	0		$ 72				85,966				(86,038)
Conversion of LP Units to Common Shares, shares			(7,204,104)
Share Issuance from/to Deferred Compensation Plan	(16)				$ (149)	149	(16)
Share Issuance from/to Deferred Compensation Plan, shares			(845)		(8,141)
Share Choice Plan Issuance Shares			(1,684)
Share Choice Plan Issuance	(55)						(55)
Stock Option Amortization	1,487						1,487
Outperformance Plan Amortization	123						123
Trustee Fees Paid in Shares	32						32
Trustee Fees Paid in Shares, shares			(2,672)
Exercise of Stock Options	$ 350		$ 1				349
Exercise of Stock Options, shares	120,180		120,179
Adjustment to Non-controlling Interest	$ 0						6,376				(6,376)
Preferred Share distributions	(7,992)									(7,992)
Distributions declared ($0.60), ($0.60), and ($0.45) per share in 2011, 2010 and 2009, respectively	(85,113)									(82,819)	(2,294)
Ending Balance at Dec. 31, 2011	$ 1,889,696	$ 43	$ 1,424	$ 0	$ 5,631	$ (5,631)	$ 2,776,197	$ 477,338	$ (6,079)	$ (1,392,332)	$ 33,105
Ending Balance, shares at Dec. 31, 2011		4,300,000	142,690,755	0	292,646

Consolidated Statements of Beneficiaries' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Distributions declared, per share	$ 0.60	$ 0.60	$ 0.60
Cumulative Distributions
Distributions declared, per share	0.60	0.60	0.45
Non-Controlling Interests
Distributions declared, per share	$ 0.60	$ 0.60	$ 0.45

Consolidated Statements of Partners' Equity - USD ($) $ in Thousands	Total	Series D Preferred Mirror Units	Accumulated Other Comprehensive Income	Non-controlling Interest Consolidated Real Estate Ventures	BRANDYWINE OPERATING PARTNERSHIP, L.P.	BRANDYWINE OPERATING PARTNERSHIP, L.P. Series D Preferred Mirror Units	BRANDYWINE OPERATING PARTNERSHIP, L.P. Series E Preferred Mirror Units	BRANDYWINE OPERATING PARTNERSHIP, L.P. General Partner Capital	BRANDYWINE OPERATING PARTNERSHIP, L.P. Accumulated Other Comprehensive Income	BRANDYWINE OPERATING PARTNERSHIP, L.P. Non-controlling Interest Consolidated Real Estate Ventures	BRANDYWINE OPERATING PARTNERSHIP, L.P. Total partners equity
Beginning Balance at Dec. 31, 2008	$ 1,722,498	$ 43	$ (17,005)	$ 52,961		$ 47,912	$ 55,538	$ 1,581,887	$ (17,005)	$ 0	$ 1,668,332
Beginning Balance, shares at Dec. 31, 2008		4,300,000				2,000,000	2,300,000	88,158,937
Net income (loss)	8,089			63	$ 8,089			$ 8,059		30	8,089
Other comprehensive income	7,086		7,376	(290)	7,086				7,086		7,086
Deferred compensation obligation								$ 131			131
Deferred compensation obligation, shares								51,058
Issuance of LP Units								$ 242,323			242,323
Issuance of LP Units, shares								40,250,000
Bonus share issuance	123							$ 123			123
Bonus share issuance, shares								36,826
Conversion of LP Units to common shares	0			(254)				$ 254			254
Conversion of LP Units to common shares, shares								7,513
Share choice plan	(46)							$ (46)			(46)
Share choice plan, shares								(7,081)
Vesting of restricted units	(212)							$ (213)			(213)
Vesting of restricted units, shares								86,172
Restricted stock amortization	3,286							$ 3,286			3,286
Restricted Performance units amortization	288							288			288
Outperformance plan amortization	927							927			927
Option amortization	602							602			602
Trustee fees paid in shares								$ 152			152
Trustee fees paid in shares, shares								13,987
Adjustment of redeemable partnership units to liquidation value at period end								$ 8,213			8,213
Adjustment to non-controlling interest										35	35
Other	678		491						491		491
Distributions to Preferred Mirror Units	(7,992)							(7,992)			(7,992)
Distributions to general partnership unitholder								(54,961)			(54,961)
Ending Balance at Dec. 31, 2009	1,921,740	$ 43	(9,138)	38,308		$ 47,912	$ 55,538	$ 1,783,033	(9,428)	65	1,877,120
Ending Balance, shares at Dec. 31, 2009		4,300,000				2,000,000	2,300,000	128,597,412
Net income (loss)	(17,606)			(532)	(17,606)			$ (17,606)			(17,606)
Other comprehensive income	7,348		7,193	155	7,348				7,348		7,348
Deferred compensation obligation								$ 0			0
Deferred compensation obligation, shares								2,409
Issuance of LP Units								$ 71,981			71,981
Issuance of LP Units, shares								5,742,268
Bonus share issuance	369							$ 369			369
Bonus share issuance, shares								32,607
Conversion of LP Units to common shares				(466)				$ 466			466
Conversion of LP Units to common shares, shares								17,468
Vesting of restricted units	(227)							$ (227)			(227)
Vesting of restricted units, shares								76,598
Restricted stock amortization	3,483							$ 3,483			3,483
Restricted Performance units amortization	965							965			965
Outperformance plan amortization	380							380			380
Option amortization	1,131							1,132			1,132
Trustee fees paid in shares								$ 98			98
Trustee fees paid in shares, shares								8,412
Exercise of options								12,761
Exercise of options, shares	37							$ 37			37
Adjustment of redeemable partnership units to liquidation value at period end								(13,839)			(13,839)
Adjustment to non-controlling interest										(27)	(27)
Cumulative effect of accounting change for variable interest entities	1,401			(38)				1,439		(38)	1,401
Distributions to Preferred Mirror Units	(7,992)							(7,992)			(7,992)
Distributions to general partnership unitholder								(80,170)			(80,170)
Ending Balance at Dec. 31, 2010	1,977,774	$ 43	(1,945)	128,272		$ 47,912	$ 55,538	$ 1,743,549	(2,080)	0	1,844,919
Ending Balance, shares at Dec. 31, 2010		4,300,000				2,000,000	2,300,000	134,485,117
Net income (loss)	(4,715)			(215)	(4,715)			$ (4,715)			(4,715)
Other comprehensive income	(4,346)		(4,134)	(212)	$ (4,346)				(4,346)		(4,346)
Deferred compensation obligation								$ (16)			(16)
Deferred compensation obligation, shares								845
Issuance of LP Units								$ 8,272			8,272
Issuance of LP Units, shares								679,285
Bonus share issuance	6							$ 6			6
Bonus share issuance, shares								463
Conversion of LP Units to common shares	0			(86,038)				$ 86,038			86,038
Conversion of LP Units to common shares, shares								7,204,104
Share choice plan	(55)							$ (55)			(55)
Share choice plan, shares								(1,684)
Common partnership units cancellation								$ 0	0	0	0
Common partnership units cancellation, shares								0
Vesting of restricted units	(350)							$ (352)			(352)
Vesting of restricted units, shares								201,464
Restricted stock amortization	2,937							$ 2,937			2,937
Restricted Performance units amortization	1,679							1,679			1,679
Outperformance plan amortization	123							123			123
Option amortization	$ 1,487							1,487			1,487
Trustee fees paid in shares								$ 32			32
Trustee fees paid in shares, shares								2,672
Exercise of options	120,180							120,179
Exercise of options, shares	$ 350							$ 350			350
Adjustment of redeemable partnership units to liquidation value at period end								5,778			5,778
Distributions to Preferred Mirror Units	(7,992)							(7,992)			(7,992)
Distributions to general partnership unitholder								(82,819)			(82,819)
Ending Balance at Dec. 31, 2011	$ 1,889,696	$ 43	$ (6,079)	$ 33,105		$ 47,912	$ 55,538	$ 1,754,302	$ (6,426)	$ 0	$ 1,851,326
Ending Balance, shares at Dec. 31, 2011		4,300,000				2,000,000	2,300,000	142,690,755

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash flows from operating activities:
Net income (loss)	$ (4,715)	$ (17,606)	$ 8,089
Adjustments to reconcile net income (loss) to net cash from operating activities:
Depreciation and amortization	219,110	214,776	210,463
Amortization of deferred financing costs	4,991	3,770	5,864
Amortization of debt discount/(premium), net	1,567	831	3,495
Straight-line rent income	(20,298)	(13,705)	(9,116)
Amortization of acquired above (below) market leases to rental renenue, net	(5,384)	(5,960)	(6,661)
Straight-line ground rent expense	1,924	1,647	1,473
Provision for doubtful accounts	1,924	2,479	5,371
Non-cash compensation expense	4,270	4,814	5,200
Recognized hedge activity	0	0	916
Provision for impairment on discontinued operations	0	0	3,700
Real estate venture income in excess of cumulative distributions	(1,175)	(4,648)	(2,512)
Loss on real estate venture formation	222	0	0
Net loss (gain) on sale of interests in real estate	(10,008)	(11,011)	(1,237)
Loss (gain) on early extinguishment of debt	2,776	2,110	(23,176)
Cumulative interest accretion of repayments of unsecured notes	(4,005)	(3,433)	(5,009)
Contributions from historic tax credit transaction, net of deferred costs	2,694	27,396	23,763
Historic tax credit transaction income	(12,026)	0	0
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	(856)	(4,173)	3,746
Other assets	(2,083)	(2,782)	2,373
Accounts payable and accrued expenses	7,732	(7,980)	(4,081)
Deferred income, gains and rent	(7,220)	(6,412)	3,059
Other liabilities	(425)	5,014	(5,315)
Net cash from operating activities	179,015	185,127	220,405
Cash flows from investing activities:
Acquisition of properties	(40,674)	(50,681)	0
Sales of properties, net	155,956	50,089	101,305
Proceeds from repayment of mortgage notes receivable	0	40,000	0
Capital expenditures	(131,156)	(180,943)	(211,892)
Advances for purchase of tenant assets, net of repayments	1,365	(1,715)	0
Loan provided to unconsolidated Real Estate Venture partner	0	(826)	0
Investment in unconsolidated Real Estate Ventures	(5,277)	(5,180)	(14,980)
Escrowed cash	0	0	31,385
Cash distributions from unconsolidated Real Estate Ventures in excess of cumulative equity income	10,316	2,205	13,062
Decrease in cash due to the deconsolidation of variable interest entities	0	(1,382)	0
Leasing costs	(38,461)	(23,503)	(21,429)
Net cash used in investing activities	(47,931)	(171,936)	(102,549)
Cash flows from financing activities:
Proceeds from Credit Facility borrowings	706,002	565,000	983,000
Repayments of Credit Facility borrowings	(613,502)	(474,000)	(1,044,000)
Proceeds from mortgage notes payable	0	256,104	149,800
Repayments of mortgage notes payable	(221,856)	(51,966)	(84,102)
Repayments from unsecured term loan	(145,500)	0	0
Proceeds from unsecured notes	321,448	0	247,030
Repayments of unsecured notes	(105,381)	(276,270)	(514,004)
Proceeds from financing activity	0	0	0
Net settlement of hedge transactions	(613)	0	(5,044)
Debt financing costs	(4,249)	(595)	(24,620)
Refund of deferred financing costs related to forward commitment	0	1,659	0
Net proceeds from issuance of shares/operating units	7,930	70,867	242,332
Exercise of stock/units options	350	37	0
Distributions paid to shareholders/unitholders	(89,559)	(87,345)	(68,914)
Distributions to noncontrolling interest	(2,309)	(1,684)	(1,691)
Net cash from (used in) financing activities	(147,239)	1,807	(120,213)
Increase (decrease) in cash and cash equivalents	(16,155)	14,998	(2,357)
Cash and cash equivalents at beginning of year	16,565	1,567	3,924
Cash and cash equivalents at end of year	410	16,565	1,567
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the years ended December 31, 2011, 2010 and 2009 of $1,997, $10,385, and $8,893, respectively	135,210	135,206	139,636
Supplemental disclosure of non-cash activity:
Note receivable issued related to the sale of the two Trenton properties, net of $12.9 million deferred gain	0	0	9,600
Settlement of note receivable through foreclosure of a parcel of land	0	(2,795)	0
Proceeds from mortgage notes payable retained by lender and included in other assets (see Note 7)	0	396	0
Change in capital expenditures financed through accounts payable at period end	(3,896)	(5,126)	7,086
Change in capital expenditures financed through retention payable at period end	(6,213)	(2,066)	5,862
Change in unfunded tenant allowance	(1,717)	0	5,986
Change in real estate investments due to the deconsolidation of variable interest entities	0	(37,126)	0
Change in mortgage notes payable due to the deconsolidation of variable interest entities	0	(42,877)	0
Change in non-controlling interest from issuance of limited partnership units (see Note 3)	0	77,733	0
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Cash flows from operating activities:
Net income (loss)	(4,715)	(17,606)	8,089
Adjustments to reconcile net income (loss) to net cash from operating activities:
Depreciation and amortization	219,110	214,776	210,463
Amortization of deferred financing costs	4,991	3,770	5,864
Amortization of debt discount/(premium), net	1,567	831	3,495
Straight-line rent income	(20,298)	(13,705)	(9,116)
Amortization of acquired above (below) market leases to rental renenue, net	(5,384)	(5,960)	(6,661)
Straight-line ground rent expense	1,924	1,647	1,473
Provision for doubtful accounts	1,924	2,479	5,371
Non-cash compensation expense	4,270	4,814	5,200
Recognized hedge activity	0	0	916
Provision for impairment on discontinued operations	0	0	3,700
Real estate venture income in excess of cumulative distributions	(1,175)	(4,648)	(2,512)
Loss on real estate venture formation	222	0	0
Net loss (gain) on sale of interests in real estate	(10,008)	(11,011)	(1,237)
Loss (gain) on early extinguishment of debt	2,776	2,110	(23,176)
Cumulative interest accretion of repayments of unsecured notes	(4,005)	(3,433)	(5,009)
Contributions from historic tax credit transaction, net of deferred costs	2,694	27,396	23,763
Historic tax credit transaction income	(12,026)	0	0
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	(856)	(4,173)	3,746
Other assets	(2,083)	(2,782)	2,373
Accounts payable and accrued expenses	7,732	(7,980)	(4,081)
Deferred income, gains and rent	(7,220)	(6,412)	3,059
Other liabilities	(425)	5,014	(5,315)
Net cash from operating activities	179,015	185,127	220,405
Cash flows from investing activities:
Acquisition of properties	(40,674)	(50,681)	0
Sales of properties, net	155,956	50,089	101,305
Proceeds from repayment of mortgage notes receivable	0	40,000	0
Capital expenditures	(131,156)	(180,943)	(211,892)
Advances for purchase of tenant assets, net of repayments	1,365	(1,715)	0
Loan provided to unconsolidated Real Estate Venture partner	0	(826)	0
Investment in unconsolidated Real Estate Ventures	(5,277)	(5,180)	(14,980)
Escrowed cash	0	0	31,385
Cash distributions from unconsolidated Real Estate Ventures in excess of cumulative equity income	10,316	2,205	13,062
Decrease in cash due to the deconsolidation of variable interest entities	0	(1,382)	0
Leasing costs	(38,461)	(23,503)	(21,429)
Net cash used in investing activities	(47,931)	(171,936)	(102,549)
Cash flows from financing activities:
Proceeds from Credit Facility borrowings	706,002	565,000	983,000
Repayments of Credit Facility borrowings	(613,502)	(474,000)	(1,044,000)
Proceeds from mortgage notes payable	0	256,104	149,800
Repayments of mortgage notes payable	(221,856)	(51,966)	(84,102)
Repayments from unsecured term loan	(145,500)	0	0
Proceeds from unsecured notes	321,448	0	247,030
Repayments of unsecured notes	(105,381)	(276,270)	(514,004)
Proceeds from financing activity	0	0	0
Net settlement of hedge transactions	(613)	0	(5,044)
Debt financing costs	(4,249)	(595)	(24,620)
Refund of deferred financing costs related to forward commitment	0	1,659	0
Net proceeds from issuance of shares/operating units	7,930	70,867	242,332
Exercise of stock/units options	350	37	0
Distributions paid to shareholders/unitholders	(91,868)	(89,029)	(70,605)
Net cash from (used in) financing activities	(147,239)	1,807	(120,213)
Increase (decrease) in cash and cash equivalents	(16,155)	14,998	(2,357)
Cash and cash equivalents at beginning of year	16,565	1,567	3,924
Cash and cash equivalents at end of year	410	16,565	1,567
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the years ended December 31, 2011, 2010 and 2009 of $1,997, $10,385, and $8,893, respectively	135,210	135,206	139,636
Supplemental disclosure of non-cash activity:
Note receivable issued related to the sale of the two Trenton properties, net of $12.9 million deferred gain	0	0	9,600
Settlement of note receivable through foreclosure of a parcel of land	0	(2,795)	0
Proceeds from mortgage notes payable retained by lender and included in other assets (see Note 7)	0	396	0
Change in capital expenditures financed through accounts payable at period end	(3,896)	(5,126)	7,086
Change in capital expenditures financed through retention payable at period end	(6,213)	(2,066)	5,862
Change in unfunded tenant allowance	(1,717)	0	5,986
Change in real estate investments due to the deconsolidation of variable interest entities	0	(37,126)	0
Change in mortgage notes payable due to the deconsolidation of variable interest entities	0	(42,877)	0
Change in non-controlling interest from issuance of limited partnership units (see Note 3)	$ 0	$ 77,733	$ 0

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Supplemental disclosure:
Capitalized interest	$ 1,997	$ 10,385	$ 8,893
Deferred gain debt			12,900
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Supplemental disclosure:
Capitalized interest	$ 1,997	$ 10,385	8,893
Deferred gain debt			$ 12,900

Organization of The Parent Company and The Operating Partnership	12 Months Ended
	Dec. 31, 2011
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION OF THE PARENT COMPANY AND THE OPERATING PARTNERSHIP	ORGANIZATION OF THE PARENT COMPANY AND THE OPERATING PARTNERSHIP The Parent Company is a self-administered and self-managed real estate investment trust (“REIT”) that provides leasing, property management, development, redevelopment, acquisition and other tenant-related services for a portfolio of office and industrial properties. The Parent Company owns its assets and conducts its operations through the Operating Partnership and subsidiaries of the Operating Partnership. The Parent Company is the sole general partner of the Operating Partnership and, as of December 31, 2011, owned a 98.1% interest in the Operating Partnership. The Parent Company’s common shares of beneficial interest are publicly traded on the New York Stock Exchange under the ticker symbol “BDN”. As of December 31, 2011, the Company owned 207 office properties, 20 industrial facilities and five mixed-use properties (collectively, the “Properties”) containing an aggregate of approximately 25.2 million net rentable square feet. In addition, as of December 31, 2011, the Company owned economic interests in 18 unconsolidated real estate ventures that contain approximately 6.7 million net rentable square feet (collectively, the “Real Estate Ventures”). As of December 31, 2011, the Company also owned 444 acres of undeveloped land, and held options to purchase approximately 52 additional acres of undeveloped land. The Properties and the properties owned by the Real Estate Ventures are located in or near Philadelphia, Pennsylvania, Metropolitan Washington, D.C., Southern and Central New Jersey, Richmond, Virginia, Wilmington, Delaware, Austin, Texas and Oakland, Concord, Carlsbad and Rancho Bernardo, California. In addition to managing properties that the Company owns, as of December 31, 2011, the Company was managing approximately 7.4 million net rentable square feet of office and industrial properties for third parties and the Real Estate Ventures. All references to building square footage, acres, occupancy percentage and the number of buildings are unaudited. The Company conducts its third-party real estate management services business primarily through six management companies (collectively, the “Management Companies”): Brandywine Realty Services Corporation (“BRSCO”), BTRS, Inc. (“BTRS”), Brandywine Properties I Limited, Inc. (“BPI”), BDN Brokerage, LLC (“BBL”), Brandywine Properties Management, L.P. (“BPM”) and Brandywine Brokerage Services, LLC (“BBS”). Each of BRSCO, BTRS and BPI is a taxable REIT subsidiary. As of December 31, 2011, the Operating Partnership owns, directly and indirectly, 100% of each of BRSCO, BTRS, BPI, BBL and BPM. As of December 31, 2011, the Management Companies were managing properties containing an aggregate of approximately 32.6 million net rentable square feet, of which approximately 25.2 million net rentable square feet related to Properties owned by the Company and approximately 7.4 million net rentable square feet related to properties owned by third parties and the Real Estate Ventures.

- Definition

The entire disclosure for the organization, consolidation and basis of presentation of financial statements disclosure, and significant accounting policies of the reporting entity. May be provided in more than one note to the financial statements, as long as users are provided with an understanding of (1) the significant judgments and assumptions made by an enterprise in determining whether it must consolidate a VIE and/or disclose information about its involvement with a VIE, (2) the nature of restrictions on a consolidated VIE's assets reported by an enterprise in its statement of financial position, including the carrying amounts of such assets, (3) the nature of, and changes in, the risks associated with an enterprise's involvement with the VIE, and (4) how an enterprise's involvement with the VIE affects the enterprise's financial position, financial performance, and cash flows. Describes procedure if disclosures are provided in more than one note to the financial statements.

+ References + Details

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2011

Accounting Policies [Abstract]

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Reclassifications

Certain amounts have been reclassified in prior years to conform to the current year presentation with no effect to previously reported net income and equity. The reclassifications are primarily due to the treatment of sold properties as discontinued operations on the statement of operations for all periods presented.

Principles of Consolidation

When the Company obtains an economic interest in an entity, the Company evaluates the entity to determine if the entity is deemed a variable interest entity (“VIE”), and if the Company is deemed to be the primary beneficiary, in accordance with the accounting standard for the consolidation of variable interest entities. The accounting standard for the consolidation of VIEs requires the Company to qualitatively assess if the Company was the primary beneficiary of the VIEs based on whether the Company had both (i) the power to direct those matters that most significantly impacted the activities of the VIE and (ii) the obligation to absorb losses or the right to receive benefits of the VIE that could potentially be significant to the VIE. For entities that the Company has determined to be VIEs but for which it is not the primary beneficiary, its maximum exposure to loss is the carrying amount of its investments, as the Company has not provided any guarantees other than the guarantee described for PJP VII which was approximately $0.7 million at December 31, 2011 (see Note 4). Also, for all entities determined to be VIEs, the Company does not provide financial support to the real estate ventures through liquidity arrangements, guarantees or other similar commitments. When an entity is not deemed to be a VIE, the Company considers the provisions of the same accounting standard to determine whether a general partner, or the general partners as a group, controls a limited partnership or similar entity when the limited partners have certain rights. The Company consolidates (i) entities that are VIEs and of which the Company is deemed to be the primary beneficiary and (ii) entities that are non-VIEs and controlled by the Company and in which the limited partners neither have the ability to dissolve the entity or remove the Company without cause nor any substantive participating rights. Entities that the Company accounts for under the equity method (i.e., at cost, increased or decreased by the Company's share of earnings or losses, plus contributions, less distributions) include (i) entities that are VIEs and of which the Company is not deemed to be the primary beneficiary (ii) entities that are non-VIEs which the Company does not control, but over which the Company has the ability to exercise significant influence and (iii) entities that are non-VIEs that the Company controls through its general partner status, but the limited partners in the entity have the substantive ability to dissolve the entity or remove the Company without cause or have substantive participating rights. The Company continuously assesses its determination of whether an entity is a VIE and who the primary beneficiary is, and whether or not the limited partners in an entity have substantive rights, more particularly if certain events occur that are likely to cause a change in the original determinations. The Company's assessment includes a review of applicable documents such as, but not limited to, applicable partnership agreements, real estate venture agreements, LLC agreements, management and leasing agreements to determine whether the Company has control to direct the business activities of the entities. The portion of the entities that are consolidated but not owned by the Company is presented as non-controlling interest as of and during the periods consolidated. All intercompany accounts and transactions have been eliminated in consolidation.

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Management makes significant estimates regarding revenue, valuation of real estate and related intangible assets and liabilities, useful lives of fixed assets, impairment of long-lived assets, equity method investments, allowance for doubtful accounts and deferred costs.

Operating Properties

Operating properties are carried at historical cost less accumulated depreciation and impairment losses. The cost of operating properties reflects their purchase price or development cost. Acquisition related costs are expensed as incurred. Costs incurred for the renovation and betterment of an operating property are capitalized to the Company’s investment in that property. Ordinary repairs and maintenance are expensed as incurred; major replacements and betterments, which improve or extend the life of the asset, are capitalized and depreciated over their estimated useful lives. Fully-depreciated assets are removed from the accounts.

Purchase Price Allocation

The Company allocates the purchase price of properties to net tangible and identified intangible assets acquired based on fair values. Above-market and below-market in-place lease values for acquired properties are recorded based on the present value (using an interest rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to the in-place leases and (ii) the Company’s estimate of the fair market lease rates for the corresponding in-place leases, measured over a period equal to the remaining non-cancelable term of the lease (includes the below market fixed renewal period). Capitalized above-market lease values are amortized as a reduction of rental income over the remaining non-cancelable terms of the respective leases. Capitalized below-market lease values are amortized as an increase to rental income over the remaining non-cancelable terms of the respective leases, including any below market fixed-rate renewal periods.

Other intangible assets also include amounts representing the value of tenant relationships and in-place leases based on the Company’s evaluation of the specific characteristics of each tenant’s lease and the Company’s overall relationship with the respective tenant. The Company estimates the cost to execute leases with terms similar to the remaining lease terms of the in-place leases, including leasing commissions, legal and other related expenses. This intangible asset is amortized to expense over the remaining term of the respective leases and any fixed-rate bargain renewal periods. Company estimates of value are made using methods similar to those used by independent appraisers or by using independent appraisals. Factors considered by the Company in this analysis include an estimate of the carrying costs during the expected lease-up periods considering current market conditions and costs to execute similar leases. In estimating carrying costs, the Company includes real estate taxes, insurance and other operating expenses and estimates of lost rentals at market rates during the expected lease-up periods, which primarily range from three to twelve months. The Company also considers information obtained about each property as a result of its pre-acquisition due diligence, marketing and leasing activities in estimating the fair value of the tangible and intangible assets acquired. The Company also uses the information obtained as a result of its pre-acquisition due diligence as part of its consideration of the accounting standard governing asset retirement obligations and when necessary, will record a conditional asset retirement obligation as part of its purchase price.

Characteristics considered by the Company in allocating value to its tenant relationships include the nature and extent of the Company’s business relationship with the tenant, growth prospects for developing new business with the tenant, the tenant’s credit quality and expectations of lease renewals, among other factors. The value of tenant relationship intangibles is amortized over the remaining initial lease term and expected renewals, but in no event longer than the remaining depreciable life of the building. The value of in-place leases is amortized over the remaining non-cancelable term of the respective leases and any fixed-rate renewal periods.

In the event that a tenant terminates its lease, the unamortized portion of each intangible, including in-place lease values and tenant relationship values, is charged to expense and market rate adjustments (above or below) are recorded to revenue.

Depreciation and Amortization

The costs of buildings and improvements are depreciated using the straight-line method based on the following useful lives: buildings and improvements (five to 55 years) and tenant improvements (the shorter of the lease term or the life of the asset).

The Company's current year consolidated statement of operations contained an out of period depreciation and amortization expense adjustment of $4.7 million relating to intangible assets representing tenant relationships and in-place leases that should have been written off in prior periods. This resulted in the overstatement of depreciation and amortization expense by $4.7 million in the current year. During the year ended December 31, 2010, depreciation and amortization expense was overstated by $1.7 million and was understated by $1.4 million, $1.8 million, $1.7 million and $1.5 million during the years ended December 31, 2009, 2008, 2007, and 2006, respectively. As management believes that this error was not material to prior years' consolidated financial statements and that the impact of recording the error in the current year is not material to the Company's consolidated financial statements, the Company recorded the related adjustment during the current year.

During 2010, the Company also recorded depreciation expense of $1.2 million related to projects completed in prior years that were not closed out of the Company’s job cost system in a timely manner. This resulted in the understatement of depreciation expense in the prior years. During the years ended December 31, 2009 and 2008, depreciation expense was understated by $0.9 million and $0.2 million, respectively. These errors, both individually and in aggregate, were not material to prior years’ consolidated financial statements and the impact of correcting this error in the current year is not material to the Company’s full year consolidated financial statements.

Construction in Progress

Project costs directly associated with the development and construction of a real estate project are capitalized as construction in progress. Construction in progress also includes costs related to ongoing tenant improvement projects. In addition, interest, real estate taxes and other expenses that are directly associated with the Company’s development activities are capitalized until the property is placed in service. Internal direct construction costs totaling $3.5 million in 2011, $3.4 million in 2010, $3.9 million in 2009 and interest totaling $2.0 million in 2011, $10.4 million in 2010, and $8.9 million in 2009 were capitalized related to development of certain Properties and land holdings.

During the years ended December 31, 2011, 2010 and 2009, the Company's internal direct construction costs are comprised entirely of capitalized salaries. The following table shows the amount of salaries (including bonuses and benefits) capitalized for the years presented (in thousands):



	December 31,
	2011		2010		2009
Development	$	—	$	2,331	$	1,772
Redevelopment	—		127		398
Tenant Improvements	3,539		940		1,757
Total	$	3,539	$	3,398	$	3,927

Impairment or Disposal of Long-Lived Assets

The Company reviews long-lived assets whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The review of recoverability is based on an estimate of the future undiscounted cash flows (excluding interest charges) expected to result from the long-lived asset’s use and eventual disposition. These cash flows consider factors such as expected future operating income, trends and prospects, as well as the effects of leasing demand, competition and other factors. If impairment exists due to the inability to recover the carrying value of a long-lived asset, an impairment loss is recorded to the extent that the carrying value exceeds the estimated fair-value of the property. The Company is required to make subjective assessments as to whether there are impairments in the values of the investments in long-lived assets. These assessments have a direct impact on its net income because recording an impairment loss results in an immediate negative adjustment to net income. The evaluation of anticipated cash flows is highly subjective and is based in part on assumptions regarding future occupancy, rental rates and capital requirements that could differ materially from actual results in future periods. Although the Company’s strategy is generally to hold its properties over the long-term, the Company will dispose of properties to meet its liquidity needs or for other strategic needs. If the Company’s strategy changes or market conditions otherwise dictate an earlier sale date, an impairment loss may be recognized to reduce the property to the lower of the carrying amount or fair value less costs to sell, and such loss could be material. If the Company determines that impairment has occurred and the assets are classified as held and used, the affected assets must be reduced to their fair value.

Where properties have been identified as having a potential for sale, additional judgments are required related to the determination as to the appropriate period over which the undiscounted cash flows should include the operating cash flows and the amount included as the estimated residual value. Management determines the amounts to be included based on a probability weighted cash flow. This requires significant judgment. In some cases, the results of whether an impairment is indicated are sensitive to changes in assumptions input into the estimates, including the hold period until expected sale.

During the Company’s impairment review for the years ended December 31, 2011 and 2010, the Company determined that no impairment charges were necessary. For the year ended December 31, 2009, the Company determined that one of its properties, during testing for impairment under the held and used model, had a historical cost greater than the probability-weighted undiscounted cash flows. Accordingly, the recorded amount was reduced to an amount equal to management’s estimate of the then current fair value. This property was sold in the second quarter of 2009.

The Company entered into development agreements related to two parcels of land under option for ground lease that require the Company to commence development by December 31, 2012. If the Company determines that it will not be able to start the construction by the date specified, or if the Company determines development is not in its best economic interest and an extension of the development period cannot be negotiated, the Company will have to write off all costs that it has incurred in preparing these parcels of land for development amounting to $7.7 million as of December 31, 2011.

Cash and Cash Equivalents

Cash and cash equivalents are highly-liquid investments with original maturities of three months or less. The Company maintains cash equivalents in financial institutions in excess of insured limits, but believes this risk is mitigated by only investing in or through major financial institutions.

Restricted Cash

Restricted cash consists of cash held as collateral to provide credit enhancement for the Company’s mortgage debt, cash for property taxes, capital expenditures and tenant improvements. Restricted cash is included in other assets as discussed below.

Accounts Receivable and Accrued Rent Receivable

Leases with tenants are accounted for as operating leases. Minimum annual rentals under tenant leases are recognized on a straight-line basis over the term of the related lease. The cumulative difference between lease revenue recognized under the straight-line method and contractual lease payment terms is recorded as “accrued rent receivable, net” on the accompanying balance sheets. Included in current tenant receivables are tenant reimbursements which are comprised of amounts recoverable from tenants for common area maintenance expenses and certain other recoverable expenses that are recognized as revenue in the period in which the related expenses are incurred. As of December 31, 2011 and 2010, no tenant represented more than 10% of accounts receivable and accrued rent receivable.

Tenant receivables and accrued rent receivables are carried net of the allowances for doubtful accounts of $3.4 million and $12.1 million in 2011, respectively and $3.7 million and $11.6 million in 2010, respectively. The allowance is an estimate based on two calculations that are combined to determine the total amount reserved. First, the Company evaluates specific accounts where it has determined that a tenant may have an inability to meet its financial obligations. In these situations, the Company uses its judgment, based on the facts and circumstances, and records a specific reserve for that tenant against amounts due to reduce the receivable to the amount that the Company expects to collect. These reserves are reevaluated and adjusted as additional information becomes available. Second, a reserve is established for all tenants based on a range of percentages applied to receivable aging categories for tenant receivables. For accrued rent receivables, the Company considers the results of the evaluation of specific accounts and also considers other factors including assigning risk factors to different industries based on its tenants SIC classification. Considering various factors including assigning a risk factor to different industries, these percentages are based on historical collection and write-off experience adjusted for current market conditions, which requires management’s judgments.

Investments in Unconsolidated Real Estate Ventures

The Company accounts for its investments in unconsolidated Real Estate Ventures under the equity method of accounting as it is not the primary beneficiary (for VIE’s) and the Company exercises significant influence, but does not control these entities under the provisions of the entities’ governing agreements pursuant to the accounting standard for the consolidation of VIEs. Under the equity method, investments in unconsolidated Real Estate Ventures are recorded initially at cost, as Investments in Real Estate Ventures, and subsequently adjusted for equity in earnings, cash contributions, less distributions and impairments. On a periodic basis, management also assesses whether there are any indicators that the value of the Company’s investments in unconsolidated Real Estate Ventures may be other than temporarily impaired. An investment is impaired only if the value of the investment, as estimated by management, is less than the carrying value of the investment and the decline is other than temporary. To the extent impairment has occurred, the loss shall be measured as the excess of the carrying amount of the investment over the value of the investment, as estimated by management. The determination as to whether an impairment exists requires significant management judgment about the fair value of its ownership interest. Fair value is determined through various valuation techniques, including but not limited to, discounted cash flow models, quoted market values and third party appraisals.

To the extent that the Company acquires an interest in or contributes assets to a Real Estate Venture project, the difference between the Company’s cost basis in the investment and the value of the Real Estate Venture or asset contributed is amortized over the life of the related assets, intangibles and liabilities and such adjustment is included in the Company’s share of equity in income of unconsolidated Real Estate Ventures. For purposes of cash flow presentation, distributions from unconsolidated Real Estate Ventures are presented as part of operating activities when they are considered as return on investments. Distributions in excess of the Company’s share in the cumulative unconsolidated Real Estate Ventures’ earnings are considered as return of investments and are presented as part of investing activities in accordance with the accounting standard for cash flow presentation.

Deferred Costs

Costs incurred in connection with property leasing are capitalized as deferred leasing costs. Deferred leasing costs consist primarily of leasing commissions and internal leasing costs that are amortized using the straight-line method over the life of the respective lease which generally ranges from one to 15 years. Management re-evaluates the remaining useful lives of leasing costs as economic and market conditions change.

Costs incurred in connection with debt financing are capitalized as deferred financing costs and charged to interest expense over the terms of the related debt agreements. Deferred financing costs consist primarily of loan fees which are amortized over the related loan term on a basis that approximates the effective interest method.

Other Assets

Other assets is comprised of the following as of December 31, 2011 (in thousands):



	December 31,
	2011		2010
Prepaid Ground Rent	$	7,615	$	7,704
Prepaid Real Estate Taxes	7,983		7,648
Rent inducements, net	7,572		6,262
Cash surrender value of life insurance	9,261		8,128
Restricted cash	2,528		4,029
Marketable securities	2,366		2,614
Prepaid insurance	2,589		2,432
Furniture, fixtures and equipment	634		1,613
Deposits on future settlements	3,884		2,035
Others	8,726		12,232
Total	$	53,158	$	54,697

Notes Receivable

As of December 31, 2011, notes receivable included a $7.2 million purchase money mortgage with a 20 year amortization period that bears interest at 8.5%, a $0.5 million loan (due in 2015) that bears interest at 10%, and a $23.4 million (including accrued but unpaid interest) seven year purchase money mortgage (due 2016) that bears interest at approximately 6% cash pay/7.64% accrual. The $23.4 million notes receivable is related to the sale of the two Trenton properties in 2009 and is presented net of the $12.9 million deferred gain in accordance with the accounting standard for installment sales (the “Trenton Note”). The Company expects to receive $27.8 million at maturity of the Trenton Note including the difference between the cash payments and the stated accrual rate.

The Company periodically assesses the collectability of the notes receivable in accordance with the accounting standard for loan receivables. The Company's $7.2 million outstanding purchase money mortgage note as mentioned above was extended to a buyer (the “Borrower”) of its parcel of land in Newtown, Pennsylvania in December 2006. During 2011, the Borrower, who is developing a residential community, defaulted on the note and as a result, a forbearance agreement was entered into between the Company and the Borrower. The Borrower also entered into another forbearance agreement with a third party senior creditor bank related to its own loan. The forbearance agreement between the Company and the Borrower outlined the repayment terms of the outstanding debt and the payment of accrued interest by the Borrower and included, among other things, the metrics for selling and settling on home sales over an agreed period of time. With the inherent credit risk in collecting interest from the note, as provided in the forbearance agreement, the Company will provide a full allowance for any accrued interest receivable. The Company has determined that the loan modification as discussed above represents a troubled debt restructuring since the Borrower was considered to be in a financial difficulty when it defaulted on the two mortgage debts and that a concession was granted in the form of the forbearance agreements. Construction has already recommenced while loan repayments are scheduled to start in 2012. The Company believes that based on terms of the forbearance agreement, the total note will be fully paid by 2014. At December 31, 2011, the Company assessed the status of the metrics outlined in the forbearance agreement and determined that the Borrower will have difficulty meeting its sales targets for the first quarter of 2012. The Borrower provided the Company and the third party senior creditor bank with expected future cash flows analysis showing its ability to meet its sales targets in 2012 to avoid being in default. The Company and the third party senior creditor bank allowed the Borrower to operate under the cash flow assumptions without amending the forbearance agreements. Given the current circumstances, the Company performed an impairment assessment of its note using the expected cash flow information provided by the Borrower and obtained third party documentation to support the assumptions used by the Borrower. The key assumptions used in the cash flow analysis included the revenue per home built; the cost to construct; the general and administrative expenses incurred to operate the business and sell homes; and the absorption assumptions used to determine the rate of home sales. The Company has determined based on the results of its probability weighted cash flow analysis that, as of December 31, 2011, the present value of the expected cash flows of the note receivable exceeded the outstanding balance of the note and therefore the note is recoverable as of December 31, 2011. However, it is still possible that the terms of the forbearance agreement may not be met due to non-performance by the Borrower of the conditions set forth in the said agreement or due to further deterioration in the housing market and could cause a loan loss of the Company's note receivable which could be material to its consolidated results of operations.

As of December 31, 2010, notes receivable included a $7.4 million purchase money mortgage with a 20 year amortization period that bears interest at 8.5%, a $0.8 million loan (due in 2015 including accrued interest) that bears interest at 10%, and a $22.9 million (including accrued but unpaid interest) seven year purchase money mortgage (due 2016) that bears interest at approximately 6% cash pay/7.64% accrual. See related discussion about the Trenton Note above. In December 2010, the Company also extended a loan to one of its unconsolidated Real Estate Venture partners. The said loan bears interest at 10% and will be due including the accrued interest in 2015.

On December 29, 2010, the Company foreclosed on one of its note receivables amounting to $2.8 million (See Note 3 for related discussion). Except for the default on the purchase money mortgage in the current year as discussed above and the foreclosure of note receivables in the prior year, there were no other collectability issues noted as of December 31, 2011 and 2010.

Revenue Recognition

Rental revenue is recognized on the straight-line basis from the later of the date of the commencement of the lease or the date of acquisition of the property subject to existing leases, which averages minimum rents over the terms of the leases. The straight-line rent adjustment increased revenue by approximately $17.9 million in 2011, $10.9 million in 2010, and $6.4 million in 2009. Deferred rents on the balance sheet represent rental revenue received prior to their due dates and amounts paid by the tenant for certain improvements considered to be landlord assets that will remain as the Company’s property at the end of the tenant’s lease term. The amortization of the amounts paid by the tenant for such improvements is calculated on a straight-line basis over the term of the tenant’s lease and is a component of straight-line rental income and increased revenue by $2.4 million in 2011, $2.8 million in 2010, and $2.7 million in 2009. Lease incentives, which are included as reductions of rental revenue in the accompanying consolidated statements of operations, are recognized on a straight-line basis over the term of the lease. Lease incentives decreased revenue by $1.6 million in 2011, $1.5 million in 2010, and $1.8 million in 2009.

Leases also typically provide for tenant reimbursement of a portion of common area maintenance and other operating expenses to the extent that a tenant’s pro rata share of expenses exceeds a base year level set in the lease or to the extent that the tenant has a lease on a triple net basis. For certain leases, significant assumptions and judgments are made by the Company in determining the lease term such as when termination options are provided to the tenant. The lease term impacts the period over which minimum rents are determined and recorded and also considers the period over which lease related costs are amortized. Termination fees received from tenants, bankruptcy settlement fees, third party management fees, labor reimbursement and leasing income are recorded when earned.

During 2011, the Company recorded additional income of $0.5 million related to electricity charges in prior years that were under-billed to a certain tenant. This resulted in the overstatement of total revenue by $0.5 million during the current year and in the understatement of total revenue by $0.3 million and $0.2 million for the years ended December 31, 2009 and 2008, respectively. As management believes that this error was not material to prior years' consolidated financial statements and that the impact of recording the error in the current year is not material to the Company's consolidated financial statements, the Company recorded the related adjustment in the current year.

No tenant represented greater than 10% of the Company’s rental revenue in 2011, 2010 or 2009.

Income Taxes

Parent Company

The Parent Company has elected to be treated as a REIT under Sections 856 through 860 of the Internal Revenue Code of 1986, as amended (the “Code”). In order to continue to qualify as a REIT, the Parent Company is required to, among other things, distribute at least 90% of its annual REIT taxable income to its shareholders and meet certain tests regarding the nature of its income and assets. As a REIT, the Parent Company is not subject to federal and state income taxes with respect to the portion of its income that meets certain criteria and is distributed annually to its shareholders. Accordingly, no provision for federal and state income taxes is included in the accompanying consolidated financial statements with respect to the operations of the Parent Company. The Parent Company intends to continue to operate in a manner that allows it to meet the requirements for taxation as a REIT. If the Parent Company fails to qualify as a REIT in any taxable year, it will be subject to federal and state income taxes and may not be able to qualify as a REIT for the four subsequent tax years. The Parent Company is subject to certain local income taxes. Provision for such taxes has been included in general and administrative expenses in the Parent Company’s Consolidated Statements of Operations and Comprehensive Income.

The tax basis of the Parent Company’s assets was $4.5 billion as of December 31, 2011 and 2010, respectively.

The Parent Company is subject to a 4% federal excise tax if sufficient taxable income is not distributed within prescribed time limits. The excise tax equals 4% of the annual amount, if any, by which the sum of (a) 85% of the Parent Company’s ordinary income and (b) 95% of the Parent Company’s net capital gain exceeds cash distributions and certain taxes paid by the Parent Company. No excise tax was incurred in 2011, 2010, or 2009.

The Parent Company may elect to treat one or more of its subsidiaries as taxable REIT subsidiaries (each a “TRS”). A TRS is subject to federal, state and local income tax. In general, a TRS may perform non-customary services for tenants, hold assets that the Parent Company, as a REIT, cannot hold directly and generally may engage in any real estate or non-real estate related business.

Operating Partnership

In general, the Operating Partnership is not subject to federal and state income taxes, and accordingly, no provision for income taxes has been made in the accompanying consolidated financial statements. The partners of the Operating Partnership are required to include their respective share of the Operating Partnership’s profits or losses in their respective tax returns. The Operating Partnership’s tax returns and the amount of allocable Partnership profits and losses are subject to examination by federal and state taxing authorities. If such examination results in changes to the Operating Partnership profits or losses, then the tax liability of the partners would be changed accordingly.

The tax basis of the Operating Partnership’s assets was $4.5 billion as of December 31, 2011 and 2010, respectively.

The Operating Partnership is subject to a 4% federal excise tax if sufficient taxable income is not distributed within prescribed time limits. The excise tax equals 4% of the annual amount, if any, by which the sum of (a) 85% of the Operating Partnership’s ordinary income and (b) 95% of the Operating Partnership’s net capital gain exceeds cash distributions and certain taxes paid by the Operating Partnership. No excise tax was incurred in 2011, 2010, or 2009.

The Operating Partnership may elect to treat one or more of its subsidiaries as REITs under Sections 856 through 860 of the Code. Each subsidiary REIT has met or intends to meet the requirements for treatment as a REIT under Sections 856 through 860 of the Code, and, accordingly, no provision has been made for federal and state income taxes in the accompanying consolidated financial statements. If any subsidiary REIT fails to qualify as a REIT in any taxable year, that subsidiary REIT will be subject to federal and state income taxes and may not be able to qualify as a REIT for the four subsequent taxable years. Also, each subsidiary REIT may be subject to certain local income taxes.

The Operating Partnership has elected to treat several of its subsidiaries as taxable TRSs, which are subject to federal, state and local income tax.

Earnings Per Unit

Basic earnings per unit is calculated by dividing income allocated to common units by the weighted-average number of units outstanding during the period. Diluted earnings per unit includes the effect of common unit equivalents outstanding during the period.

Treasury Shares

The Company accounts for its treasury share purchases using the cost method. Since repurchase, shares have been reissued at an amount less than their cost basis. The losses on reissuances are charged to the cumulative earnings of the Company using the FIFO basis. As of December 31, 2011, none of the treasury shares remained outstanding. As of December 31, 2010, the total number of treasury shares outstanding was 116,679 shares.

Stock-Based Compensation Plans

The Parent Company maintains a shareholder-approved equity-incentive plan known as the Amended and Restated 1997 Long-Term Incentive Plan (the “1997 Plan”). The 1997 Plan is administered by the Compensation Committee of the Parent Company’s Board of Trustees. Under the 1997 Plan, the Compensation Committee is authorized to award equity and equity-based awards, including incentive stock options, non-qualified stock options, restricted shares and performance-based shares. On June 2, 2010, the Parent Company’s shareholders approved amendments to the 1997 Plan that, among other things, increased the number of common shares available for future awards under the 1997 Plan by 6,000,000 (of which 3,600,000 shares are available solely for options and share appreciation rights). As of December 31, 2011, 5,789,202 common shares remained available for future awards under the 1997 Plan (including 3,971,774 shares available solely for options and share appreciation rights). Through December 31, 2011, all options awarded under the 1997 Plan had a one to ten-year term.

The Company incurred stock-based compensation expense of $6.4 million during 2011, of which $1.5 million was capitalized as part of the Company’s review of employee salaries eligible for capitalization. The Company recognized stock-based compensation expense of $6.1 million and $5.3 million during 2010 and 2009, of which $1.3 million and $0.8 million, respectively, were also capitalized. The expensed amounts are included in general and administrative expense on the Company’s consolidated income statement in the respective periods.

Comprehensive Income

Comprehensive income or loss is recorded in accordance with the provisions of the accounting standard for comprehensive income. The accounting standard establishes standards for reporting comprehensive income and its components in the financial statements. Comprehensive income includes unrealized gains and losses on available-for-sale securities and the effective portions of changes in the fair value of derivatives.

Accounting for Derivative Instruments and Hedging Activities

The Company accounts for its derivative instruments and hedging activities in accordance with the accounting standard for derivative and hedging activities. The accounting standard requires the Company to measure every derivative instrument (including certain derivative instruments embedded in other contracts) at fair value and record them in the balance sheet as either an asset or liability. See disclosures below related to the Company’s adoption of the accounting standard for fair value measurements and disclosures.

For derivatives designated as fair value hedges, the changes in fair value of both the derivative instrument and the hedged item are recorded in earnings. For derivatives designated as cash flow hedges, the effective portions of changes in the fair value of the derivative are reported in other comprehensive income while the ineffective portions are recognized in earnings. During the year ended December 31, 2009, the Company recorded a $(1.1) million fair value adjustment in its consolidated statements of operations related to two of its interest swaps in which the hedging relationship ceased due to the issuance of its unsecured notes on September 25, 2009. The ineffective portions of the hedges are recognized in earnings. During the year ended December 31, 2009, the Company recognized a gain of $0.1 million for the ineffective portion of its forward starting swaps prior to the termination of the hedging relationship (See Note 9).

The Company actively manages its ratio of fixed-to-floating rate debt. To manage its fixed and floating rate debt in a cost-effective manner, the Company, from time to time, enters into interest rate swap agreements as cash flow hedges, under which it agrees to exchange various combinations of fixed and/or variable interest rates based on agreed upon notional amounts.

Fair Value Measurements

The Company estimates the fair value of its outstanding derivatives and available-for-sale-securities in accordance with the accounting standard for fair value measurements and disclosures. The accounting standard defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. It also establishes a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The standard describes three levels of inputs that may be used to measure fair value. Financial assets and liabilities recorded on the Consolidated Balance Sheets are categorized based on the inputs to the valuation techniques as follows:


•	Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access;

•

Level 2 inputs are inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs may include quoted prices for similar assets and liabilities in active markets, as well as inputs that are observable for the asset or liability (other than quoted prices), such as interest rates, foreign exchange rates, and yield curves that are observable at commonly quoted intervals; and


•	Level 3 inputs are unobservable inputs for the asset or liability, which is typically based on an entity’s own assumptions, as there is little, if any, related market activity or information.

In instances where the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the entire fair value measurement falls is based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the asset or liability.

The following table sets forth the Company’s financial assets and liabilities that were accounted for at fair value on a recurring basis as of December 31, 2011 (in thousands):



	Fair Value Measurements at Reporting Date Using:
Description	December 31, 2011		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Unobservable Inputs (Level 3)
Recurring
Assets:
Available-for-Sale Securities	$	—	$	—	$	—	$	—

Liabilities:
Interest Rate Swaps	$	3,886	$	—	$	3,886	$	—

The following table sets forth the Company’s financial assets and liabilities that were accounted for at fair value on a recurring basis as of December 31, 2010 (in thousands):



	Fair Value Measurements at Reporting Date Using:
Description	December 31, 2010		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Unobservable Inputs (Level 3)
Recurring
Assets:
Available-for-Sale Securities	$	248	$	248	$	—	$	—

Non-financial assets and liabilities recorded at fair value on a non-recurring basis to which the Company would apply the accounting standard where a measurement was required under fair value would include:


•	Non-financial assets and liabilities initially measured at fair value in an acquisition or business combination that are not remeasured at least annually at fair value,


•	Long-lived assets measured at fair value due to an impairment in accordance with the accounting standard for the impairment or disposal of long-lived assets,


•	Equity and cost method investments measured at fair value due to an impairment in accordance with the accounting standard for investments,


•	Notes receivable adjusted for any impairment in its value in accordance with the accounting standard for loan receivables; and


•	Asset retirement obligations initially measured at fair value under the accounting standard for asset retirement obligations.

There were no items that were accounted for at fair value on a non-recurring basis as of December 31, 2011.

Accounting Pronouncements Adopted During 2011

In June 2011, the Financial Accounting Standards Board (FASB) issued an amendment to the accounting standard for the presentation of comprehensive income. The amendment requires entities to present the total of comprehensive income, the components of net income, and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. In addition, the amendment requires entities to present on the face of the financial statements reclassification adjustments for items that are reclassified from other comprehensive income to net income in the statement(s) where the components of net income and the components of other comprehensive income are presented. This amendment is effective for fiscal years and interim periods beginning after December 15, 2011. The Company's adoption of the new standard will not have a material impact on its consolidated financial position or results of operations as the amendment relates only to changes in financial statement presentation.

In May 2011, the FASB issued amendments to the accounting standard for fair value measurements and disclosures. The amendments change the wording used to describe many of the requirements in U.S. GAAP for measuring fair value and for disclosing information about fair value measurements. The amendments are intended to create comparability of fair value measurements presented and disclosed in financial statements prepared in accordance with U.S. GAAP and International Financial Reporting Standards. These amendments are effective for fiscal years and interim periods beginning after December 15, 2011. The Company's adoption of the new standard will not have a material impact on its consolidated financial position or results of operations.

In December 2010, the FASB issued a new accounting standard for the disclosure of supplementary pro-forma information for business combinations. This guidance clarifies that the disclosure of supplementary pro-forma information for business combinations should be presented such that revenues and earnings of the combined entity are calculated as though the relevant business combinations that occurred during the current reporting period had occurred as of the beginning of the comparable prior annual reporting period. The guidance also seeks to improve the usefulness of the supplementary pro-forma information by requiring a description of the nature and amount of material, non-recurring pro-forma adjustments that are directly attributable to the business combinations. This new standard is effective for business combinations with an acquisition date on or after the beginning of the first annual reporting period beginning on or after December 15, 2010. The Company's adoption of this new standard did not have a material impact on its consolidated financial position or results of operations.

Real Estate Investments

12 Months Ended

Dec. 31, 2011

Real Estate [Abstract]

REAL ESTATE INVESTMENTS

As of December 31, 2011 and 2010, the gross carrying value of the Company’s Properties was as follows (in thousands):



	December 31,
	2011		2010
Land	$	677,891	$	697,724
Building and improvements	3,631,388		3,693,579
Tenant improvements	483,801		442,808
	$	4,793,080	$	4,834,111

Acquisitions and Dispositions

2011

Brandywine-AI Venture

On December 20, 2011, the Company formed a joint venture, Brandywine - AI Venture LLC, (the "Venture"), with Current Creek Investments, LLC ("Current Creek"), a wholly-owned subsidiary of Allstate Insurance Company. The Company and Current Creek each own a 50% interest in the Venture. The Venture owns three office properties, which the Company to the Venture upon its formation. The contributed office properties contain an aggregate of 587,317 net rentable square feet of and consist of 3130 and 3141 Fairview Park Drive, both located in Falls Church, Virginia, and 7101 Wisconsin Avenue located in Bethesda, Maryland. Concurrent with the Company's contribution of the three properties to the Venture, Current Creek contributed approximately $32.2 million (net of closing costs and customary prorations) to the capital of the Venture and the Venture closed on non-recourse fixed rate mortgage loans in the aggregate amount of $90.0 million, secured by mortgages on each of the three properties. The mortgage loans have a weighted-average maturity of 7.4 years and bear interest at a weighted average rate of 4.4%. The Venture transferred the properties to the Venture based on a $156.0 million valuation. Upon formation of the Venture, the Company received $120.1 million of aggregate proceeds from these transactions net of $2.9 million of transaction and venture formation costs. The Company used the net proceeds to reduce its outstanding indebtedness under its Prior Credit Facility and for general corporate purposes.

Based on facts and circumstances at Venture formation, the Company has determined that the Venture is not a VIE in accordance with the accounting standard for the consolidation of VIEs. As a result, the Company used the voting interest model under the accounting standard for consolidation to determine if it will consolidate the Venture. Based on the provisions within the joint venture agreement, the Company and Current Creek have shared control rights and the Company does not have exclusive control over the properties. Since control is shared, 3130 Fairview Park and 7101 Wisconsin Avenue were deconsolidated by the Company and are accounted for under the equity method of accounting. The Company recorded a net loss on partial sale of $0.1 million related to these two office properties which is included as part of the loss on venture formation in the Company's consolidated statements of operations together with the related $0.1 million basis adjustment on the Company's equity method investment in the Venture. As of December 31, 2011, the carrying amount of the Company's equity investment in this Venture amounted to $24.7 million.

The Company will continue to maintain a regional management and leasing office in 3141 Fairview Park. Consistent with the other two properties, financial control is shared, however, pursuant to the accounting standard for sales-leaseback transactions, the lease maintained by the Company at 3141 Fairview Park and its 50% ownership interest in the Venture results in the Company having continued involvement that will require the property and its related operations to be consolidated by the Company under the financing method. The Company recorded a mortgage debt of $22.0 million and a $7.5 million financing obligation as part of other liabilities in the Company's balance sheet representing the cash it received from the Venture related to this transaction. The Company recognized a nominal amount of interest expense related to the other partner's portion of the property's operation, from Venture formation through December 31, 2011. As of December 31, 2011, the balance of the financing obligation amounted to $7.5 million.

The Company's continuing involvement with the properties through its interest in the Venture and its management and leasing activities represents a significant continuing involvement in the properties. Accordingly, under the accounting standard for reporting discontinued operations, the Company has determined that the loss on partial sale and the operations of the properties should not be included as part of discontinued operations in its consolidated statements of operations.

Acquisitions

On August 12, 2011, the Company acquired an office property located in Philadelphia, Pennsylvania, together with related ground tenancy rights under a long-term ground lease, through the foreclosure of a note receivable amounting to $18.8 million under which the said property was encumbered. The Company obtained the note receivable from a third party on August 2, 2011 which was funded through an advance under its Credit Facility and with available corporate funds. The office property contains 192,707 of net rentable square feet and is currently 57.2% leased as of December 31, 2011. The Company recognized $0.3 million of transaction costs to acquire the office property which is included as part of general and administrative expenses in the Company's consolidated statements of operations. On the acquisition date of the office property, the total purchase price was allocated as follows: $21.4 million to building, $12.0 million to intangible assets and $14.4 million to below market lease liabilities assumed. The Company also acquired other assets of $0.2 million and assumed certain liabilities of $0.4 million.

On March 28, 2011, the Company acquired two office properties totaling 126,496 of net rentable square feet in Glen Allen, Virginia known as Overlook I and II for $12.6 million. The acquired properties are 100% leased as of December 31, 2011. The Company funded the acquisition price through an advance under its Credit Facility and with available corporate funds. The Company recognized a nominal amount of acquisition related costs, which are included as part of general and administrative expenses in the Company's consolidated statements of operations.

On January 20, 2011, the Company acquired a one acre parcel of land in Philadelphia, Pennsylvania for $9.3 million. The Company funded the cost of this acquisition with available corporate funds and a draw on its Credit Facility. The Company capitalized $0.5 million of acquisition related and other costs as part of land inventory on its consolidated balance sheet. On December 29, 2011, the Company contributed the acquired property into a newly formed real estate venture known as Brandywine 1919 Market Ventures (the "1919 Ventures") in return for a 50% general partner interest in the venture. 1919 Ventures is expected to construct a mixed-use development property in the city of Philadelphia. The Company has determined that 1919 Ventures is a VIE due to insufficient equity at the date of formation. It was also determined that the Company will not consolidate 1919 Ventures as both partners have shared power in the venture. Prior to the formation of 1919 Ventures, the Company received $4.9 million from the other partner in anticipation of the real estate venture formation. The amount received was accounted for as a distribution from 1919 Ventures and accordingly reduced the Company's equity investment in the venture in the Company's consolidated balance sheet as of December 31, 2011.

Dispositions

On November 22, 2011, the Company sold 442 Creamery Way, a 104,500 net rentable square feet office property located in Exton, PA, for a sales price of $7.4 million. The property was 100.0% occupied as of the date of sale.

On October 28, 2011, the Company sold two office properties (Five Greentree and Lake Center II) containing a total of 206,243 net rentable square feet located in Marlton, NJ for an aggregate sales price of $22.8 million. Five Greentree and Lake Center II were 92.2% and 47.8% occupied, respectively, as of the date of sale.

On October 14, 2011, the Company sold an undeveloped parcel of land in Dallas, Texas containing six acres of land for $0.6 million.

On June 27, 2011, the Company sold Three Greentree Center, a 69,300 net rentable square feet office property located in Marlton, New Jersey, for a sales price of $5.9 million. The property was 13.9% occupied as of the date of sale.

During the first quarter of the 2011, the Company recognized a $2.8 million net gain upon the sale of its remaining 11% ownership interest in three properties which it partially sold to one of its unconsolidated Real Estate Ventures in December 2007. The Company had retained an 11% equity interest in these properties subject to a put/call at fixed prices for a period of three years from the time of the sale. In January 2011, the Company exercised the put/call and transferred full ownership in the three properties to the Real Estate Venture. Accordingly, the Company's direct continuing involvement through its 11% interest in the properties ceased as a result of the transfer of the ownership interest. The Company has also presented the gain as part of its continuing operations in its consolidated statements of operations because of its prior significant continuing involvement with the properties through its interest in the unconsolidated Real Estate Venture and its management and leasing activities at the properties.

2010

Acquisitions

On August 5, 2010, the Company acquired a 53 story Class A office tower at 1717 Arch Street (“Three Logan Square”) in Philadelphia, Pennsylvania, together with related ground tenancy rights under a long-term ground lease, from BAT Partners, L.P. Three Logan Square contains approximately 1.0 million of net rentable square feet and is 67.2% leased as of December 31, 2011. The Company acquired Three Logan Square for approximately $129.0 million funded through a combination of $51.2 million in cash and the issuance of 7,111,112 units of limited partnership interest in the Operating Partnership designated as “Class F (2010) Units.” The Class F (2010) Units did not accrue any dividends and were not entitled to allocations of income or loss prior to August 5, 2011, the first anniversary of the closing. Total cash paid after the assumption of security deposit obligations of existing tenants in the property of $0.9 million amounted to $50.3 million. The assumed security deposit obligation is included in other liabilities in the Company’s consolidated balance sheets.The Company funded the cash portion of the acquisition price through an advance under its Prior Credit Facility and with available corporate funds.

For purposes of computing the total purchase price, the Class F (2010) Units were valued based on the closing market price of the Parent Company’s common shares on the acquisition date of $11.54 less the annual dividend rate per share of $0.60 to reflect that these units do not begin to accrue a dividend prior to August 5, 2011. The Class F (2010) Units were subject to redemption at the option of the holder after the first anniversary of the acquisition. The Operating Partnership had the option to satisfy the redemption either for an amount, per unit, of cash equal to the market price of one of the Parent Company’s common shares (based on the five-day trading average ending on the date of the exchange) or for one of the Parent Company’s common shares. On December 23, 2011, the Operating Partnership satisfied in full BAT Partners, L.P.'s tender for redemption of all 7,111,112 of the Class F (2010) Units through the issuance of 7,111,112 of the Parent Company's common shares.

The Company accounted for the acquisition using the acquisition method of accounting. As discussed in Note 2, the Company utilized a number of sources in making estimates of fair values for purposes of allocating the purchase price to tangible and intangibles assets acquired and intangible liabilities assumed. The purchase price is allocated as follows (in thousands):



	August 5,
	2010
Building and tenant improvements	$	98,188
Intangible assets acquired	28,856
Below market lease liabilities assumed	(683		)
Total	$	126,361

Intangible assets acquired and intangible liabilities assumed consist of the following (in thousands):



	August 5, 2010		Weighted Average Amortization Period (in years)
Intangible assets:
In-place lease value	$	13,584	3
Tenant relationship value	8,870		5
Above market tenant leases acquired	895		1
Below market ground lease acquired	5,507		82
Total	$	28,856	23
Intangible liabilities:
Below market leases acquired	$	683	1

The Company also recognized tenant and other receivables of $1.1 million and prepaid real estate taxes of $1.5 million from the acquisition and both are included as part of the accounts receivable and the other asset sections, respectively, of the Company’s consolidated balance sheets.

The Company recognized $0.4 million of acquisition related costs which are included as part of general and administrative expenses of the Company’s consolidated statements of operations.

The operating results of the acquired property are included in the Company’s results of operations from the acquisition date and are presented below (in thousands):



	For the period from August 5 to December 31, 2010
Revenue:
Rents	$	6,347
Tenant Reimbursements	933
Other	45
Total revenue	$	7,325
Loss from operations (includes depreciation and intangible asset amortization)	$	(3,602	)

The unaudited pro forma information below summarizes the Company’s combined results of operations for the years ended December 31, 2010 and 2009 as though the acquisition of Three Logan Square was completed on January 1, 2009. The supplemental pro forma operating data is not necessarily indicative of what the actual results of operations would have been assuming the transaction had been completed as set forth above, nor do they purport to represent the Company’s results of operations for future periods (in thousands except for per share amounts).



	December 31,
	2010			2009
	(unaudited)
Pro forma revenues	$	582,642		$	604,440
Pro forma income (loss) from continuing operations	(29,000		)	7,890
Pro forma net income (loss) available to common shareholders	(24,940		)	2,306
Earnings per common share from continuing operations:
Basic — as reported	$	(0.29	)	$	(0.04	)
Basic — as pro forma	$	(0.28	)	$	—
Diluted — as reported	$	(0.29	)	$	(0.04	)
Diluted — as pro forma	$	(0.28	)	$	—
Earnings per common share:
Basic — as reported	$	(0.19	)	$	—
Basic — as pro forma	$	(0.19	)	$	0.02
Diluted — as reported	$	(0.19	)	$	—
Diluted — as pro forma	$	(0.19	)	$	0.02

On December 29, 2010, the Company acquired a 12 acre parcel of land in Gibbsboro, New Jersey through the foreclosure of a note receivable amounting to $2.8 million under which the said property was encumbered. The Company paid transaction related costs of $0.3 million which was capitalized as part of land inventory in the Company’s consolidated balance sheets. The parcel of land is held for future development.

Dispositions

On December 23, 2010, the Company sold four office properties (One and Two Greentree Centre, 8000 Lincoln Drive, and Lake Center IV) containing a total of 243,195 net rentable square feet in Marlton, New Jersey for an aggregate sales price of $20.9 million. These properties were 76.1% occupied at the date of sale.

On November 22, 2010, the Company sold Spyglass Point, a 58,576 net rentable square feet office property located in Austin, Texas for a sales price of $13.5 million. This property was fully occupied at the date of sale.

On September 20, 2010, the Company sold 630 Clark Avenue, a 50,000 net rentable square feet office property located in King of Prussia, Pennsylvania for a sales price of $3.6 million. This property was fully occupied at the date of sale.

On August 18, 2010, the Company sold 479 Thomas Jones Way, a 49,264 net rentable square feet office property located in Exton, Pennsylvania, for a sales price of $3.8 million. This property was 63.0% occupied at the date of sale.

On January 14, 2010, the Company sold Westmoreland Plaza, a 121,815 net rentable square feet office property located in Richmond, Virginia, for a sales price of $10.8 million. This property was vacant at the date of sale.

All sales presented above are included within discontinued operations (see Note 10).

- Definition

The entire disclosure for certain real estate investment financial statements, real estate investment trust operating support agreements, real estate owned, retail land sales, time share transactions, as well as other real estate related disclosures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 57
-Paragraph 2
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph c
-Subparagraph Schedule III
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 28
-Article 12

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 6
-Subparagraph a
-Article 5

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher OTS
-Name Federal Regulation (FR)
-Number Title 12
-Chapter V
-Section 563c.102
-Paragraph 11
-Subsection I
-LegacyDoc This is a non-GAAP reference that was included in the 2009 taxonomy. It will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 3
-Section A
-Paragraph 9
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 154
-Paragraph 22
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 67
-Paragraph 4, 5, 6, 7
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 46R
-Paragraph 23, 24
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 01-6
-Paragraph 13
-Subparagraph f
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 15
-Paragraph 28
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 75-2
-Paragraph 47, 51, 52
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Audit and Accounting Guide (AAG)
-Number AAG-DEP
-Chapter 11
-Paragraph 2, 6, 9-11, 18, 20
-IssueDate 2006-05-01
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 04-2
-Paragraph 41, 63, 64
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 7, 34
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 34
-Paragraph 9, 11, 12, 13, 14, 15, 21
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 17: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 66
-Paragraph 4, 5, 37, 50, 59, 65, 95, 97
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher OTS
-Name Federal Regulation (FR)
-Number Title 12
-Chapter V
-Section 563c.102
-Paragraph 10
-Subparagraph a, b
-Subsection I
-LegacyDoc This is a non-GAAP reference that was included in the 2009 taxonomy. It will be removed from future versions of this taxonomy.

Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 10
-Subparagraph 4
-Article 9

Reference 20: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 11
-Article 9

Reference 21: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 970
-SubTopic 360
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-28)
-URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024

+ Details

Investment in Unconsolidated Ventures

12 Months Ended

Dec. 31, 2011

Equity Method Investments and Joint Ventures [Abstract]

INVESTMENT IN UNCONSOLIDATED VENTURES

As of December 31, 2011, the Company had an aggregate investment of approximately $115.8 million in its 18 actively operating unconsolidated Real Estate Ventures. The Company formed these ventures with unaffiliated third parties, or acquired interests in them, to develop or manage office properties or to acquire land in anticipation of possible development of office properties. As of December 31, 2011, 15 of the Real Estate Ventures own 52 office buildings that contain an aggregate of approximately 6.7 million net rentable square feet, two Real Estate Ventures own four acres of undeveloped land and one Real Estate Venture developed a hotel property that contains 137 rooms in Conshohocken, PA.

The Company accounts for its unconsolidated interests in its Real Estate Ventures using the equity method. The Company’s unconsolidated interests range from 20% to 65%, subject to specified priority allocations in certain of the Real Estate Ventures.

The amounts reflected in the following tables (except for the Company’s share of equity and income) are based on the historical financial information of the individual Real Estate Ventures. One of the Real Estate Ventures, acquired in connection with the Prentiss Properties Trust merger in 2006, had a negative equity balance on a historical cost basis as a result of historical depreciation and distribution of excess financing proceeds. The Company reflected its acquisition of this Real Estate Venture interest at its relative fair value as of the date of the merger. The difference between allocated cost and the underlying equity in the net assets of the investee is accounted for as if the entity were consolidated (i.e., allocated to the Company’s relative share of assets and liabilities with an adjustment to recognize equity in earnings for the appropriate depreciation/amortization). The Company does not record operating losses of the Real Estate Ventures in excess of its investment balance unless the Company is liable for the obligations of the Real Estate Venture or is otherwise committed to provide financial support to the Real Estate Venture.

The Company’s investment in Real Estate Ventures as of December 31, 2011 and the Company’s share of the Real Estate Ventures’ income (loss) for the year ended December 31, 2011 was as follows (in thousands):



	Ownership Percentage (a)		Carrying Amount			Company’s Share of 2011 Real Estate Venture Income (Loss)			Real Estate Venture Debt at 100%		Current Interest Rate		Debt Maturity
Broadmoor Austin Associates	50	%	$	66,150		$	197		$	66,810	7.04	%	Apr-2023
Brandywine-AI Venture LLC (b)	50	%	24,670			(278		)	68,000		(b)		(b)
Macquarie BDN Christina LLC	20	%	6,168			875			60,000		4.50	%	June-2016
One Commerce Square (c)	25	%	5,100			242			128,529		5.67	%	Dec-15
Brandywine 1919 Ventures (d)	50	%	4,882			—			—		N/A		N/A
Two Commerce Square (c)	25	%	3,415			224			107,112		6.30	%	May-13
1000 Chesterbrook Blvd.	50	%	1,745			245			26,000		4.75	%	Dec-21
Four Tower Bridge (e)	65	%	1,360			702			10,870		5.20	%	Feb-21
G&I Interchange Office LLC (DRA — N. PA) (f)	20	%	1,239			76			181,967		5.78	%	Jan-15
Residence Inn Tower Bridge	50	%	481			433			14,261		5.63	%	Feb-16
PJP VII	25	%	472			190			8,072		L+1.55%		Nov-13
PJP V	25	%	361			116			5,789		6.47	%	Aug-19
PJP II	30	%	300			138			4,263		6.12	%	Nov-23
Six Tower Bridge (e)	63	%	201			126			12,599		7.79	%	Aug-12
Two Tower Bridge	35	%	134			(364		)	13,482		(g)		(g)
Seven Tower Bridge	20	%	105			—			11,182		(h)		(h)
PJP VI	25	%	31			67			8,834		6.08	%	Apr-23
Eight Tower Bridge	3.4	%	—			583			—
Coppell Associates (e)	50	%	(1,007		)	(139		)	18,060		(i)		(i)
Five Tower Bridge			—			60
Invesco, L.P.			—			282
			$	115,807		$	3,775		$	745,830


(a)	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.


(b)	See Note 3 for related discussion about the Brandywine-AI Venture, LLC formation.

(c)

During November, 2010, the Company acquired a 25% interest in two partnerships which own One and Two Commerce Square buildings in Philadelphia, PA. The other partner holds the remaining 75% interest in each of the two partnerships. In accordance with the accounting guidance for joint ventures, the Company is currently recognizing its preferred return from the real estate ventures as income on its invested capital. After the other partner has recognized the losses equal to its invested capital, the Company will begin to recognize its share from the results of the real estate ventures in proportion to its ownership interests.


(d)	See Note 3 for related discussion about the Brandywine 1919 Market Ventures formation.


(e)	As a result of the adoption of the new accounting standard for the consolidation of variable interest entities, the Company deconsolidated these three real estate ventures as of January 1, 2010.


(f)	Proceeds received by the Company from the sale of an 80% ownership stake in the properties exceeded the historical cost of those properties. Accordingly, no investment in the real estate venture was reflected on the balance sheet at period end.


(g)	Consists of a $10.1 million fixed rate mortgage with a 5.72% interest rate and May 2013 maturity date; also includes $3.4 million municipal and state borrowings with nominal interest rates (0 — 1%) and maturity dates from 3 to 10 years.

(h)

Comprised of two fixed rate mortgages: $7.0 million and $1.0 million. Both mature in February 2013 and accrue interest at a fixed rate of 4% through February 2012, and 5% through February 2013. The total loan amount of $11.2 million as presented above also includes a 3% fixed rate loan (interest only through maturity) with a balance of $1.2 million as of December 31, 2011. This loan can be increased up to $1.3 million through its maturity date of September 2025. The remaining $2.0 million of the total amount features a 4% fixed rate with interest only through its maturity date of February 2014.


(i)	Comprised of two fixed rate mortgages: a senior fixed rate note of $16.4 million at 5.75% that matures in March 2016 and a junior fixed rate note of $1.6 million at 6.89% that matures in December 2013; 5.89% is the blended rate.

The following is a summary of the financial position of the unconsolidated Real Estate Ventures in which the Company had investment interests as of December 31, 2011 and 2010 (in thousands):



	December 31,
	2011		2010
Net property	$	846,643	$	804,705
Other assets	110,520		105,576
Other Liabilities	48,798		44,509
Debt	745,830		748,387
Equity	162,535		117,385
Company’s share of equity (Company’s basis)	115,807		84,372

The following is a summary of results of operations of the unconsolidated Real Estate Ventures in which the Company had interests as of December 31, 2011, 2010 and 2009 (in thousands):



	Years ended December 31,
	2011 (a)		2010 (a)		2009
Revenue	$	145,867	$	118,923	$	105,236
Operating expenses	63,715		44,942		38,691
Interest expense, net	42,032		37,505		30,858
Depreciation and amortization	39,172		32,703		36,700
Net income	948		3,773		(1,012		)
Company’s share of income (Company’s basis)	3,775		5,305		4,069


(a) -	Includes the three real estate ventures that were deconsolidated upon the adoption of the accounting standard for the consolidation of VIEs on January 1, 2010.

As of December 31, 2011, the aggregate principal payments of recourse and non-recourse debt payable to third-parties are as follows (in thousands):




2011	$	24,228
2012	143,705
2013	13,809
2014	306,051
2015	97,215
Thereafter	160,822
	$	745,830

As of December 31, 2011, the Company had guaranteed repayment of approximately $0.7 million of loans on behalf of a certain Real Estate Venture. The Company also provides customary environmental indemnities in connection with construction and permanent financing both for its own account and on behalf of its Real Estate Ventures.

- Definition

The entire disclosure for equity investment, or group of investments, for which combined disclosure is appropriate, including: (a) the name of each investee and percentage of ownership of common stock, (b) accounting policies for investments in common stock, (c) difference between the amount at which the investment is carried and the amount of underlying equity in net assets and the accounting treatment of the difference, (d) the total fair value of each identified investment for which a market value is available, (e) summarized information as to assets, liabilities, and results of operations of the investees (for investments in unconsolidated subsidiaries, common stock of joint ventures, or other investments using the equity method), and (f) material effects of possible conversions, exercises, or contingent issuances of the investee. Other disclosures include (a) the names of any investee in which the investor owns 20 percent or more of the voting stock and investment is not accounted for using the equity method, and the reasons why not, and (b) the names of any investee in which the investor owns less than 20 percent of the voting stock and the investment is accounted for using the equity method, and the reasons why it is.

+ References + Details

Deferred Costs

12 Months Ended

Dec. 31, 2011

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

DEFERRED COSTS

As of December 31, 2011 and 2010, the Company’s deferred costs were comprised of the following (in thousands):



	December 31, 2011
	Total Cost		Accumulated Amortization			Deferred Costs, net
Leasing Costs	$	140,772	$	(50,990	)	$	89,782
Financing Costs	38,929		(13,349		)	25,580
Total	$	179,701	$	(64,339	)	$	115,362



	December 31, 2010
	Total Cost		Accumulated Amortization			Deferred Costs, net
Leasing Costs	$	123,724	$	(43,930	)	$	79,794
Financing Costs	37,257		(10,934		)	26,323
Total	$	160,981	$	(54,864	)	$	106,117

During 2011, 2010 and 2009, the Company capitalized internal direct leasing costs of $6.6 million, $6.2 million and $5.3 million, respectively, in accordance with the accounting standard for the capitalization of leasing costs.

Intangible Assets And Liabilities

12 Months Ended

Dec. 31, 2011

Goodwill and Intangible Assets Disclosure [Abstract]

INTANGIBLE ASSETS AND LIABILITIES

As of December 31, 2011 and 2010, the Company’s intangible assets/liabilities were comprised of the following (in thousands):



	December 31, 2011
	Total Cost		Accumulated Amortization			Intangibles, net
In-place lease value	$	91,426	$	(55,498	)	$	35,928
Tenant relationship value	72,813		(45,114		)	27,699
Above market leases acquired	12,744		(5,856		)	6,888
Total	$	176,983	$	(106,468	)	$	70,515

Below market leases acquired	$	75,685	$	(40,579	)	$	35,106



	December 31, 2010
	Total Cost		Accumulated Amortization			Intangibles, net
In-place lease value	$	108,456	$	(63,010	)	$	45,446
Tenant relationship value	95,385		(52,113		)	43,272
Above market leases acquired	18,319		(9,575		)	8,744
Total	$	222,160	$	(124,698	)	$	97,462

Below market leases acquired	$	67,198	$	(37,965	)	$	29,233

For the years ended December 31, 2011, 2010, and 2009, the Company wrote off through the acceleration of amortization approximately $7.4 million, $1.5 million and $2.4 million, respectively, of intangible assets as a result of tenant move-outs prior to the end of the associated lease term. For the year ended December 31, 2011, the Company accelerated amortization of approximately $0.2 million of intangible liabilities as a result of tenant move-outs. For the year ended December 31, 2010, the Company accelerated amortization of a nominal amount of intangible liabilities as a result of tenant move-outs. For the year ended December 31, 2009, the Company accelerated amortization of approximately $0.4 million of intangible liabilities as a result of tenant move-outs.

As of December 31, 2011, the Company’s annual amortization for its intangible assets/liabilities is as follows (in thousands, assumes no early terminations):



	Assets		Liabilities
2012	$	20,457	$	6,826
2013	12,457		6,312
2014	9,606		4,745
2015	7,207		2,597
2016	4,565		1,704
Thereafter	16,223		12,922
Total	$	70,515	$	35,106

Debt Obligations

12 Months Ended

Dec. 31, 2011

Debt Disclosure [Abstract]

DEBT OBLIGATIONS

The following table sets forth information regarding the Company’s consolidated debt obligations outstanding at December 31, 2011 and 2010 (in thousands):



Property / Location	December 31, 2011			December 31, 2010			Effective Interest Rate			Maturity Date
MORTGAGE DEBT:
Arboretum I, II, III & V	$	—		$	20,386		7.59	%	(a)	Jul-11
Midlantic Drive/Lenox Drive/DCC I	—			56,514			8.05	%	(b)	Oct-11
Research Office Center	—			39,145			5.30	%	(c), (d)	Oct-11
Concord Airport Plaza	—			34,494			5.55	%	(d), (e)	Jan-12
Newtown Square/Berwyn Park/Libertyview	56,538			58,102			7.25	%		May-13
Southpoint III	1,887			2,597			7.75	%		Apr-14
Tysons Corner	94,882			96,507			5.36	%	(d)	Aug-15
Two Logan Square	89,800			89,800			7.57	%		Apr-16
One Logan Square	—			60,000			4.50	%	(f)	Jul-16
Fairview Eleven Tower	22,000			—			4.25	%		Jan-17
IRS Philadelphia Campus	202,905			208,366			7.00	%		Sep-30
Cira South Garage	44,379			46,335			7.12	%		Sep-30
Principal balance outstanding	512,391			712,246
Plus: unamortized fixed-rate debt premiums (discounts), net	(1,330		)	(457		)
Total mortgage indebtedness	$	511,061		$	711,789
UNSECURED DEBT:
$345.0M 3.875% Guaranteed Exchangeable Notes due 2026	—			59,835			5.50	%	(g)	Oct-11
Bank Term Loan	37,500			183,000			LIBOR+0.80%		(h)	Jun-12
Credit Facility	275,500			183,000			LIBOR+0.725%		(h)	Jun-12
$300.0M 5.750% Guaranteed Notes due 2012	151,491			175,200			5.73	%		Apr-12
$250.0M 5.400% Guaranteed Notes due 2014	242,681			242,681			5.53	%		Nov-14
$250.0M 7.500% Guaranteed Notes due 2015	227,329			250,000			7.77	%		May-15
$250.0M 6.000% Guaranteed Notes due 2016	250,000			250,000			5.95	%		Apr-16
$300.0M 5.700% Guaranteed Notes due 2017	300,000			300,000			5.68	%		May-17
$325.0M 4.950% Guaranteed Notes due 2018	325,000			—			5.14	%		Apr-18
Indenture IA (Preferred Trust I)	27,062			27,062			2.75	%		Mar-35
Indenture IB (Preferred Trust I)	25,774			25,774			3.30	%		Apr-35
Indenture II (Preferred Trust II)	25,774			25,774			LIBOR+1.25%			Jul-35
Principal balance outstanding	1,888,111			1,722,326
Less: unamortized exchangeable debt discount	—			(906		)
unamortized fixed-rate debt discounts, net	(5,177		)	(2,763		)
Total unsecured indebtedness	$	1,882,934		$	1,718,657
Total Debt Obligations	$	2,393,995		$	2,430,446


(a)	On April 1, 2011, the Company prepaid the remaining balance of the loan without penalty.


(b)	On June 3, 2011, the Company prepaid the remaining balance of the loan without penalty.


(c)	On June 30, 2011, the Company prepaid the remaining balance of the loan without penalty. The unamortized fixed-rate debt premium of $0.3 million related to this loan was included as part of the gain (loss) on early extinguishment of debt in the Company's consolidated statement of operations during the current year.


(d)	These loans were assumed upon acquisition of the related properties. The interest rates reflect the market rate at the time of acquisition.


(e)	On September 1, 2011, the Company prepaid the remaining balance of the loan without penalty. The unamortized fixed-rate debt premium of $0.2 million related to this loan was included as part of the gain (loss) on early extinguishment of debt in the Company's consolidated statement of operations during the year.


(f)	This mortgage was subject to an interest rate floor of 4.50% on a monthly basis. On July 11, 2011, the Company prepaid the balance of the loan without penalty.

(g)

On October 20, 2011, holders representing $59.5 million of the outstanding Exchangeable Notes exercised their right to cause the Company to redeem their notes at par plus accrued and unpaid interest leaving an outstanding balance of $0.4 million. On December 8, 2011, the Company redeemed the remaining balance of the Exchangeable Notes pursuant to its right under the indenture agreement (see related discussion below).

(h)

On March 31, 2011, the maturity dates of the Bank Term Loan and the Credit Facility were extended to June 29, 2012 from June 29, 2011. On June 29, 2011, the Company paid a total extension fee amounting to $1.2 million which is equal to 15 basis points of the outstanding principal balance of the Bank Term Loan and of the committed amount under the Credit Facility. The extension of the maturity dates was at the Company's option under the Bank Term Loan and the Credit Facility agreements. There were no changes in the terms and conditions of the loan agreements as a result of the maturity date extensions. On December 15, 2011, the Company entered into binding agreements for lender commitments related a new $600.0 million four -year unsecured credit facility (the "New Credit Facility") and three unsecured term loans in the same aggregate amount of $600.0 million (collectively, the “New Term Loans”), consisting of a $150.0 million three-year loan, a $250.0 million four-year loan and a $200.0 million seven-year loan. Please see below for a related discussion regarding the New Credit Facility and Term Loans.

During 2011, 2010 and 2009, the Company’s weighted-average effective interest rate on its mortgage notes payable was 6.72%, 6.59% and 6.45%, respectively. As of December 31, 2011 and 2010, the net carrying value of the Company’s Properties that are encumbered by mortgage indebtedness was $678.0 million and $989.8 million, respectively.

During the year ended December 31, 2011, the Company repurchased $106.2 million of its outstanding unsecured Notes in a series of transactions which are summarized in the table below (excluding accrued interest, in thousands):



Notes	Repurchase Amount		Principal		Loss		Deferred Financing Amortization
2011 3.875% Notes	$	59,835	$	59,835	$	—	$	—
2012 5.750% Notes	24,749		23,709		868		32
2015 7.500% Notes	25,140		22,671		2,396		120
	$	109,724	$	106,215	$	3,264	$	152

The Parent Company unconditionally guarantees the unsecured debt obligations of the Operating Partnership (or is a co-borrower with the Operating Partnership) but does not, by itself incur indebtedness.

The Company utilizes its unsecured revolving credit facility (the Credit Facility) borrowings for general business purposes, including the acquisition, development and redevelopment of properties and the repayment of other debt. The maturity date of the Credit Facility in place at December 31, 2011 was June 29, 2012. The per annum variable interest rate on the outstanding balances was LIBOR plus 0.725%. The interest rate and facility fee are subject to adjustment upon a change in the Company’s unsecured debt ratings. As of December 31, 2011, the Company had $275.5 million of borrowings, and $2.5 million in letters of credit outstanding, leaving $322.0 million of unused availability under the Credit Facility. During the years ended December 31, 2011 and 2010, the weighted-average interest rate on Credit Facility borrowings was 0.99% and 1.03%, respectively. As of December 31, 2011 and 2010, the weighted average interest rate on the Credit Facility was 1.01% and 1.02%, respectively.

The Credit Facility requires the maintenance of ratios related to minimum net worth, debt-to-total capitalization and fixed charge coverage and includes non-financial covenants. The Company was in compliance with all financial covenants as of December 31, 2011.

The Company entered into binding agreements for lender commitments related to a New Credit Facility and New Term Loans as mentioned above. The Company closed on the New Credit Facility and Term Loans on February 1, 2012 and used the initial advances under the New Term Loans to repay all balances outstanding under, and concurrently terminate, its existing Credit Facility and the Bank Term Loan, both of which were scheduled to mature on June 29, 2012.

The Company has the option to increase the amounts available to be advanced under the New Credit Facility, the $150.0 million three-year term loan, and the $250.0 million four-year term loan by an aggregate of $200.0 million, subject to customary conditions and limitations, by obtaining additional commitments from the current lenders and other financial institutions. The Company also has the option to extend the maturity dates of each of the New Credit Facility, the $150.0 million three-year term loan and the $250.0 million four-year term loan by one year, subject to payment of an extension fee and other customary conditions and limitations. The $150.0 million three-year term and the $250.0 million four-year term loans can be prepaid by the Company at any time without penalty. The $200.0 million seven-year term loan is subject to a declining prepayment penalty ranging from 3.00% a year after closing, 2.00% after two years, 1.00% after three years and without penalty thereafter.

The spread to LIBOR for LIBOR-based loans under the New Credit Facility and New Term Loans will depend on the Company's unsecured senior debt credit rating. Based on the Company's current credit rating, the spread for such loans will be 150, 175, 175 and 190 basis points under the New Credit Facility, the $150.0 million three-year term loan, the $250.0 million four-year term loan and the $200.0 million seven-year term loan, respectively. At the Company's option, loans under the New Credit Facility and New Term Loans may also bear interest at a per annum floating rate equal to the higher of the prime rate or the federal funds rate plus 0.50% per annum. The New Credit Facility contains a competitive bid option that allows banks that are part of the lender consortium to bid to make loans to the Company at a reduced rate. The Company executed hedging transactions that fix the rate on the $200.0 million seven-year term loan at a 3.623% average for its full term, the rate on $300.0 million of notional principal for the other loans at rates in a range of 2.470% to 2.910% for periods of three to five years. All hedges commenced on February 1, 2012 and the rates are inclusive of the LIBOR spread based on the current investment grade rating. See Note 9 for details of the interest rate swaps entered into as of December 31, 2011.

The New Credit Facility and New Term Loans contain financial and operating covenants and restrictions.

The Company accounted for its outstanding 3.875% Guaranteed Exchangeable Notes in accordance with the accounting standard for convertible debt instruments. The accounting standard requires the initial proceeds from convertible debt that may be settled in cash to be bifurcated between a liability component and an equity component. The accounting standard requires the initial proceeds from the Company’s issuance of the 3.875% Guaranteed Exchangeable Notes to be allocated between a liability component and an equity component in a manner that reflects interest expense at the interest rate of a similar nonconvertible debt that could have been issued by the Company at such time. This is accomplished through the creation of a discount on the debt that would be accreted using the effective interest method as additional non-cash interest expense over the period the debt is expected to remain outstanding (i.e. through the first optional redemption date).

On December 8, 2011, the Company redeemed the remaining balance of the 3.875% Exchangeable Notes pursuant to its right under the indenture agreement. The principal amount outstanding of the 3.875% Guaranteed Exchangeable Notes was $59.8 million at December 31, 2010. The carrying amount of the equity component is $24.4 million and is reflected within additional paid-in capital in the Company’s consolidated balance sheets. The debt discount was fully amortized through October 15, 2011. The unamortized debt discount was $0.9 million at December 31, 2010. The effective interest rate at December 31, 2010 was 5.5%. The Company recognized contractual coupon interest of $1.9 million and $3.2 million for the years ended December 31, 2011 and 2010, respectively. In addition, the Company recognized interest on amortization of debt discount of $0.9 million and $1.6 million during the years ended December 31, 2011 and 2010, respectively. There were no debt discount write-offs resulting from debt repurchases for the year ended December 31, 2011. Debt discount write-offs resulting from debt repurchases amounted to $2.0 million for the years ended December 31, 2010.

On August 26, 2010, the Company received $254.0 million of gross proceeds from a $256.5 million forward financing commitment it obtained on June 29, 2009. The Company paid a $17.7 million commitment fee in connection with this commitment. The loan proceeds, together with the commitment fee, had been escrowed with an institutional trustee pending the completion of the development of the IRS Philadelphia Campus and the Cira South Garage as well as the commencement of the leases at these facilities. The financing consists of two separate loans of $209.7 million secured by the IRS Philadelphia Campus and $46.8 million secured by the Cira South Garage. The lender held back $2.5 million of the loan proceeds pending the completion of certain conditions related to the IRS Philadelphia Campus and Cira South Garage. As of December 31, 2011, the Company has received $2.1 million of the total amounts held back. The loans are non-recourse and are secured by the IRS Philadelphia Campus and Cira South Garage, respectively. The loans bear interest of 5.93% per annum with interest only through September 10, 2010 and thereafter require principal and interest monthly payments through its maturity in September 2030. As of December 31, 2011, total financing costs related to this transaction amounted to $19.9 million which is included as part of the deferred costs in the Company’s consolidated balance sheet and will be amortized over the 20 year term of the loans using the effective interest rate method. The total financing costs included the commitment fee which was reduced to $16.0 million after the receipt of a refund resulting from the overpayment made on the commitment fee of $1.7 million. Other related transaction costs included as part of total financing costs amounted to $3.8 million. The Company used the loan proceeds to reduce borrowings under its Credit Facility and for general corporate purposes.

As of December 31, 2011, the Company’s aggregate scheduled principal payments of debt obligations are as follows (in thousands):



2012	$	476,889
2013	66,806
2014	254,787
2015	327,225
2016	347,065
Thereafter	927,730
Total principal payments	2,400,502
Net unamortized premiums/(discounts)	(6,507		)
Outstanding indebtedness	$	2,393,995

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References + Details

Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2011

Fair Value Disclosures [Abstract]

FAIR VALUE OF FINANCIAL INSTRUMENTS

The following fair value disclosure was determined by the Company using available market information and discounted cash flow analyses as of December 31, 2011 and 2010, respectively. The discount rate used in calculating fair value is the sum of the current risk free rate and the risk premium on the date measurement of the instruments or obligations. Considerable judgment is necessary to interpret market data and to develop the related estimates of fair value. Accordingly, the estimates presented are not necessarily indicative of the amounts that the Company could realize upon disposition. The use of different estimation methodologies may have a material effect on the estimated fair value amounts. The Company believes that the carrying amounts reflected in the Consolidated Balance Sheets at December 31, 2011 and 2010 approximate the fair values for cash and cash equivalents, accounts receivable, other assets, accounts payable and accrued expenses.

The following are financial instruments for which the Company estimates of fair value differ from the carrying amounts (in thousands):



	December 31, 2011					December 31, 2010
	Carrying Amount			Fair Value		Carrying Amount			Fair Value
Mortgage payable, net of premiums	$	512,391		$	545,784	$	712,246		$	726,348
Unsecured notes payable, net of discounts	$	1,496,501		$	1,555,633	$	1,277,716		$	1,338,743
Variable Rate Debt Instruments	$	391,610		$	380,786	$	444,610		$	432,556
Notes Receivable	$	31,157	(a)	$	32,756	$	31,216	(a)	$	28,921


(a)	For purposes of this disclosure, one of the notes is presented gross of the deferred gain of $12.9 million arising from the sale of the two Trenton properties in 2009 accounted for under the accounting standard for installment sales.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44A, 44B
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15C, 15D
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15A
-Subparagraph a-d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 15B
-Subparagraph a, b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 3, 10, 14, 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32, 33, 34
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 17-22, 27, 28
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13537-108611

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13433-108611

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 30
-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14172-108612

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13504-108611

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19296-110258

+ Details

Risk Management and Use of Financial Instruments

12 Months Ended

Dec. 31, 2011

Derivative Instruments and Hedging Activities Disclosure [Abstract]

RISK MANAGEMENT AND USE OF FINANCIAL INSTRUMENTS

Risk Management

In the course of its on-going business operations, the Company encounters economic risk. There are three main components of economic risk: interest rate risk, credit risk and market risk. The Company is subject to interest rate risk on its interest-bearing liabilities. Credit risk is primarily the risk of inability or unwillingness of tenants to make contractually required payments and counterparties on derivatives not fulfilling their obligations. Market risk is the risk of declines in the value of properties due to changes in rental rates, interest rates or other market factors affecting the valuation of properties held by the Company.

Risks and Uncertainties

Significantly challenging and sluggish economic conditions have reduced the volume of real estate transactions and created credit stresses on many businesses. Vacancy rates may increase through 2012 and possibly beyond as the current economic climate negatively impacts tenants in the Properties. The current financial markets also have an adverse effect on the Company’s other counter parties such as the counter parties in its derivative contracts.

The Company expects that the impact of the current state of the economy, including high unemployment and the unprecedented volatility in the financial and credit markets, will continue to have a dampening effect on the fundamentals of its business, including increases in past due accounts, tenant defaults, lower occupancy and reduced effective rents. These conditions would negatively affect the Company’s future net income and cash flows and could have a material adverse effect on its financial condition.

The Company’s Credit Facility, Bank Term Loan and the indenture governing the unsecured public debt securities (Note 7) contain restrictions, requirements and other limitations on the ability to incur indebtedness, including total debt to asset ratios, secured debt to total asset ratios, debt service coverage ratios and minimum ratios of unencumbered assets to unsecured debt which it must maintain. The ability to borrow under the Credit Facility is subject to compliance with such financial and other covenants. In the event that the Company fails to satisfy these covenants, it would be in default under the Credit Facility, the Bank Term Loan and the indenture and may be required to repay such debt with capital from other sources. Under such circumstances, other sources of capital may not be available, or may be available only on unattractive terms.

Availability of borrowings under the Credit Facility is subject to a traditional material adverse effect clause. Each time the Company borrows it must represent to the lenders that there have been no events of a nature which would have a material adverse effect on the business, assets, operations, condition (financial or otherwise) or prospects of the Company taken as a whole or which could negatively effect the ability of the Company to perform its obligations under the Credit Facility. While the Company believes that there are currently no material adverse effect events, the Company is operating in unprecedented economic times and it is possible that such event could arise which would limit the Company’s borrowings under the Credit Facility. If an event occurs which is considered to have a material adverse effect, the lenders could consider the Company in default under the terms of the Credit Facility and the borrowings under the Credit Facility would become due and payable. If the Company is unable to obtain a waiver, this would have a material adverse effect on the Company’s financial position and results of operations.

The Company was in compliance with all financial covenants as of December 31, 2011. Management continuously monitors the Company’s compliance with and anticipated compliance with the covenants. Certain of the covenants restrict management’s ability to obtain alternative sources of capital. While the Company currently believes it will remain in compliance with its covenants, in the event of a continued slow-down and continued crisis in the credit markets, the Company may not be able to remain in compliance with such covenants and if the lender would not provide a waiver, it could result in an event of default.

Use of Derivative Financial Instruments

The Company’s use of derivative instruments is limited to the utilization of interest rate agreements or other instruments to manage interest rate risk exposures and not for speculative purposes. The principal objective of such arrangements is to minimize the risks and/or costs associated with the Company’s operating and financial structure, as well as to hedge specific transactions. The counterparties to these arrangements are major financial institutions with which the Company and its affiliates may also have other financial relationships. The Company is potentially exposed to credit loss in the event of non-performance by these counterparties. However, because of the high credit ratings of the counterparties, the Company does not anticipate that any of the counterparties will fail to meet these obligations as they come due. The Company does not hedge credit or property value market risks through derivative financial instruments.

The Company formally assesses, both at inception of the hedge and on an on-going basis, whether each derivative is highly-effective in offsetting changes in cash flows of the hedged item. If management determines that a derivative is not highly-effective as a hedge or if a derivative ceases to be a highly-effective hedge, the Company will discontinue hedge accounting prospectively. The related ineffectiveness would be charged to the consolidated statement of operations.

The valuation of these instruments is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves.

To comply with the provisions of the accounting standard for fair value measurements and disclosures, the Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees.

The following table summarizes the terms and fair values of the Company's derivative financial instruments as of December 31, 2011. The Company has no existing derivative financial instruments at December 31, 2010. The notional amounts provide an indication of the extent of the Company's involvement in these instruments at that time, but do not represent exposure to credit, interest rate or market risks (amounts presented in thousands).



Hedge Product	Hedge Type	Designation		Notional Amount		Strike		Trade Date	Maturity Date	Fair value
Swap	Interest Rate	Cash Flow	(a)	$	200,000	3.623	%	December 6-13, 2011	February 1, 2019	$	2,820
Swap	Interest Rate	Cash Flow	(a)	127,000		2.702	%	December 9-13, 2011	February 1, 2016	340
Swap	Interest Rate	Cash Flow	(a)	50,000		2.470	%	December 13, 2011	February 1, 2015	65
Swap	Interest Rate	Cash Flow	(a)	23,000		2.513	%	December 7-12, 2011	May 1, 2015	27
Swap	Interest Rate	Cash Flow	(a)	27,062		2.750	%	December 21, 2011	September 30, 2017	244
Swap	Interest Rate	Cash Flow	(a)	25,774		3.300	%	December 22, 2011	January 30, 2021	390
				$	452,836					$	3,886

(a) Hedging unsecured variable rate debt.

On March 31, 2011, in anticipation of the offering of $325.0 million of 4.95% unsecured guaranteed notes due April 15, 2018, the Company also entered into seven intra-day treasury lock agreements. The treasury lock agreements were designated as cash flow hedges on interest rate risk and qualified for hedge accounting. The total notional amount of the treasury lock agreements was $230.0 million with an expiration of seven years at treasury rates of 2.891%, 2.873%, and 2.858% and a fair value of $0.6 million at March 31, 2011. The agreements were settled on the day we completed the debt offering at a total cost of $0.6 million. This cost was recorded as a component of accumulated other comprehensive income in the accompanying consolidated balance sheet and will be amortized over the term of the note.

Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, in connection with the Company's interest swaps as of December 31, 2011, the intra-day treasury lock agreement that the Company entered into and the interest swaps which matured on October 18, 2010, the Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy.

The fair values of the hedges as of December 31, 2011 were included in other liabilities and accumulated other comprehensive income in the Company's consolidated balance sheet , except for the $1.1 million fair value adjustment of the hedges charged as an expense to the consolidated statements of operations during the year ended December 31, 2009, relating to two of its interest rate swaps which were both cash settled in December 2009. The hedging relationship with these swaps ceased upon the Company’s issuance of its unsecured notes on September 25, 2009. Accordingly, changes in the fair value of these interest rate swaps were charged to the consolidated statements of operations until they were cash settled. The Company also recognized a gain of $0.1 million from the ineffectiveness of the hedges during the year ended December 31, 2009 prior to the termination of the hedging relationship.

Concentration of Credit Risk

Concentrations of credit risk arise when a number of tenants related to the Company’s investments or rental operations are engaged in similar business activities, or are located in the same geographic region, or have similar economic features that would cause their inability to meet contractual obligations, including those to the Company, to be similarly affected. The Company regularly monitors its tenant base to assess potential concentrations of credit risk. Management believes the current credit risk portfolio is reasonably well diversified and does not contain any unusual concentration of credit risk. No tenant accounted for 10% or more of the Company’s rents during 2011, 2010 and 2009. Recent developments in the general economy and the global credit markets have had a significant adverse effect on companies in numerous industries. The Company has tenants concentrated in various industries that may be experiencing adverse effects from the current economic conditions and the Company could be adversely affected if such tenants go into default on their leases.

- Definition

The entire disclosure for the entity's entire derivative instruments and hedging activities. Describes an entity's risk management strategies, derivatives in hedging activities and non-hedging derivative instruments, the assets, obligations, liabilities, revenues and expenses arising therefrom, and the amounts of and methodologies and assumptions used in determining the amounts of such items.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 45
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6887037&loc=d3e80784-113994

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5579245-113959

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624163-113959

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624171-113959

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6935481&loc=d3e41638-113959

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5580258-113959

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5579240-113959

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6935481&loc=d3e41641-113959

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6935481&loc=d3e41620-113959

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4E
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624181-113959

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5618551-113959

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624177-113959

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6887037&loc=d3e80748-113994

Reference 17: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624258-113959

Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4K
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5708775-113959

Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6935481&loc=d3e41635-113959

Reference 20: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(n))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 21: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4J
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5708773-113959

Reference 22: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6441202&loc=d3e80720-113993

+ Details

Discontinued Operations

12 Months Ended

Dec. 31, 2011

Discontinued Operations and Disposal Groups [Abstract]

DISCONTINUED OPERATIONS

For the years ended December 31, 2011, 2010 and 2009, income from discontinued operations relates to an aggregate of 19 properties containing approximately 1.6 million net rentable square feet that the Company has sold since January 1, 2009.

The following table summarizes revenue and expense information for the properties sold which qualify for discontinued operations reporting since January 1, 2009 (in thousands):



	Years ended December 31,
	2011			2010		2009
Revenue:
Rents	$	3,779		$	9,363	$	19,095
Tenant reimbursements	1,198			3,678		8,453
Termination fees	33			190		—
Other	(50		)	70		238
Total revenue	4,960			13,301		27,786
Expenses:
Property operating expenses	1,717			4,641		9,884
Real estate taxes	559			1,816		3,769
Depreciation and amortization	1,431			4,185		7,173
Total operating expenses	3,707			10,642		20,826
Income from discontinued operations before gain on sale of interests in real estate	1,253			2,659		6,960
Net gain on disposition of discontinued operations	7,264			11,011		1,241
Provision for impairment	—			—		(3,700		)
Income from discontinued operations	$	8,517		$	13,670	$	4,501

Discontinued operations have not been segregated in the consolidated statements of cash flows. Therefore, amounts for certain captions will not agree with respective data in the consolidated statements of operations.

- Definition

The entire disclosure for the facts and circumstances leading to the completed or expected disposal, manner and timing of disposal, the gain (loss) recognized in the income statement and the income statement caption that includes that gain (loss), amounts of revenues and pretax profit or loss reported in discontinued operations, the segment in which the disposal group was reported, and the classification (whether sold or classified as held for sale) and carrying value of the assets and liabilities comprising the disposal group. Includes all disposal groups, including those classified as components of the entity (discontinued operations).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 43-48
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2941-110230

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1510-107760

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e1020-107759

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e1012-107759

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e957-107759

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1474-107760

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6390789&loc=d3e2443-110228

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1436-107760

+ Details

Non Controlling Interests in The Parent Company	12 Months Ended
Non Controlling Interests in The Parent Company	Dec. 31, 2011
Noncontrolling Interest [Abstract]
NON-CONTROLLING INTERESTS IN THE PARENT COMPANY	NON-CONTROLLING INTERESTS IN THE PARENT COMPANY Non-controlling interests in the Parent Company’s financial statements relate to redeemable common limited partnership interests in the Operating Partnership held by parties other than the Parent Company and interests held by third party partners in the previously consolidated real estate ventures. Operating Partnership As of December 31, 2011 and 2010, the aggregate book value of the non-controlling interest associated with the redeemable common limited partnership interests in the accompanying consolidated balance sheet was $33.1 million and $128.3 million, respectively. The Parent Company believes that the aggregate settlement value of these interests (based on the number of units outstanding and the closing price of the common shares on the balance sheet date) was approximately $25.6 million and $115.4 million, respectively.

- Definition

The entire disclosure for noncontrolling interest in consolidated subsidiaries, which could include the name of the subsidiary, the ownership percentage held by the parent, the ownership percentage held by the noncontrolling owners, the amount of the noncontrolling interest, the location of this amount on the balance sheet (when not reported separately), an explanation of the increase or decrease in the amount of the noncontrolling interest, the noncontrolling interest share of the net Income or Loss of the subsidiary, the location of this amount on the income statement (when not reported separately), the nature of the noncontrolling interest such as background information and terms, the amount of the noncontrolling interest represented by preferred stock, a description of the preferred stock, and the dividend requirements of the preferred stock.

+ References + Details

Beneficiaries Equity of the Parent Company

12 Months Ended

Dec. 31, 2011

Equity [Abstract]

BENEFICIARIES' EQUITY OF THE PARENT COMPANY

BENEFICIARIES’ EQUITY OF THE PARENT COMPANY

Earnings per Share (EPS)

The following table details the number of shares and net income used to calculate basic and diluted earnings per share (in thousands, except share and per share amounts; results may not add due to rounding):



	Years ended December 31,
	2011						2010						2009
	Basic			Diluted			Basic			Diluted			Basic			Diluted
Numerator
Income (loss) from continuing operations	$	(13,232	)	$	(13,232	)	$	(31,276	)	$	(31,276	)	$	3,588		$	3,588
Net (loss) income from continuing operations attributable to non-controlling interests	548			548			820			820			58			58
Amount allocable to unvested restricted shareholders	(505		)	(505		)	(512		)	(512		)	(279		)	(279		)
Preferred share dividends	(7,992		)	(7,992		)	(7,992		)	(7,992		)	(7,992		)	(7,992		)
Loss from continuing operations available to common shareholders	(21,181		)	(21,181		)	(38,960		)	(38,960		)	(4,625		)	(4,625		)
Income from discontinued operations	8,517			8,517			13,670			13,670			4,501			4,501
Discontinued operations attributable to non-controlling interests	(332		)	(332		)	(288		)	(288		)	(121		)	(121		)
Discontinued operations attributable to common shareholders	8,185			8,185			13,382			13,382			4,380			4,380
Net loss available to common shareholders	$	(12,996	)	$	(12,996	)	$	(25,578	)	$	(25,578	)	$	(245	)	$	(245	)
Denominator
Weighted-average shares outstanding	135,444,424			135,444,424			131,743,275			131,743,275			111,898,045			111,898,045
Contingent securities/Stock based compensation	—			—			—			—			—			1,353,246
Total weighted-average shares outstanding	135,444,424			135,444,424			131,743,275			131,743,275			111,898,045			113,251,291
Earnings (loss) per Common Share:
Loss from continuing operations attributable to common shareholders	$	(0.16	)	$	(0.16	)	$	(0.29	)	$	(0.29	)	$	(0.04	)	$	(0.04	)
Discontinued operations attributable to common shareholders	0.06			0.06			0.10			0.10			0.04			0.04
Net loss attributable to common shareholders	$	(0.10	)	$	(0.10	)	$	(0.19	)	$	(0.19	)	$	—		$	—

Redeemable limited partnership units totaling 2,698,647 in 2011, 9,902,752 in 2010, and 2,809,108 in 2009 were excluded from the earnings per share computations because their effect would have been antidilutive.

The contingent securities/stock based compensation impact is calculated using the treasury stock method and relates to employee awards settled in shares of the Parent Company. The effect of these securities is anti-dilutive for periods that the Parent Company incurs a net loss available to common shareholders and therefore is excluded from the dilutive earnings per share calculation in such periods.

Unvested restricted shares are considered participating securities which require the use of the two-class method for the computation of basic and diluted earnings per share. For the twelve months ended December 31, 2011, 2010 and 2009, earnings representing nonforfeitable dividends as noted in the table above were allocated to the unvested restricted shares issued to the Company's executives and other employees under the 1997 Plan.

Common and Preferred Shares

On December 23, 2011, the Parent Company issued 7,111,112 of its common shares in exchange for an equal number of Class F (2010) Units of the Operating Partnership. The Class F (2010) Units were issued in August 2010 as part of the acquisition of an office property and were subject to redemption at the option of the holder after the first anniversary of the issuance. The Operating Partnership had the option to satisfy the redemption either for an amount, per unit, of cash equal to the market price of one of the Parent Company's common shares (based on the five-day trading average ending on the date of the exchange) or for one of the Parent Company's common shares for each unit redeemed. On December 23, 2011, the Operating Partnership satisfied in full BAT Partners, L.P.'s tender for redemption of all 7,111,112 of the Class F (2010) Units through the issuance of 7,111,112 Parent Company's common shares.

On December 13, 2011, the Parent Company declared a distribution of $0.15 per common share, totaling $21.5 million, which was paid on January 19, 2012 to shareholders of record as of January 5, 2012. On December 13, 2011, the Parent Company declared distributions on its Series C Preferred Shares and Series D Preferred Shares to holders of record as of December 30, 2011. These shares are entitled to a preferential return of 7.50% and 7.375%, respectively. Distributions paid on January 17, 2012 to holders of Series C Preferred Shares and Series D Preferred Shares totaled $0.9 million and $1.1 million, respectively.

In March 2010, the Parent Company commenced a continuous equity offering program (the “Offering Program”), under which the Parent Company may sell up to an aggregate amount of 15,000,000 common shares until March 10, 2013. The Company may sell common shares in amounts and at times to be determined by the Parent Company. Actual sales will depend on a variety of factors as determined by the Company, including market conditions, the trading price of its common shares and determinations by the Parent Company of the appropriate sources of funding. In conjunction with the Offering Program, the Parent Company engages sales agents who received compensation, in aggregate, of up to 2% of the gross sales price per share sold. During the year ended December 31, 2011, the Parent Company sold 679,285 shares under the Offering Program at an average sales price of $12.18 per share resulting in net proceeds of $8.0 million. The Parent Company contributed the net proceeds from the sale of its shares to the Operating Partnership in exchange for the issuance of 679,285 common partnership units to the Parent Company. The Operating Partnership used the net proceeds from the sales contributed by the Parent Company to repay balances on its Credit Facility and for general corporate purposes. From the inception of the Offering Program in March 2010 through December 31, 2011, the Parent Company has sold 6,421,553 shares under this program resulting in 8,578,447 remaining shares available for sale.

In 2003, the Parent Company issued 2,000,000 7.50% Series C Cumulative Redeemable Preferred Shares (the “Series C Preferred Shares”) for net proceeds of $48.1 million. The Series C Preferred Shares are perpetual. On or after December 30, 2008, the Parent Company, at its option, may redeem the Series C Preferred Shares, in whole or in part, by paying $25.00 per share, which is equivalent to its liquidation preference, plus accrued but unpaid dividends. See Note 13 for related discussion.

In 2004, the Parent Company issued 2,300,000 7.375% Series D Cumulative Redeemable Preferred Shares (the “Series D Preferred Shares”) for net proceeds of $55.5 million. The Series D Preferred Shares are perpetual. On or after February 27, 2009, the Parent Company, at its option, may redeem the Series D Preferred Shares, in whole or in part, by paying $25.00 per share, which is equivalent to its liquidation preference, plus accrued but unpaid dividends. The Parent Company could not redeem Series D Preferred Shares before February 27, 2009 except to preserve its REIT status. See Note 13 for related discussion.

Common Share Repurchases

The Parent Company maintains a share repurchase program pursuant to which the Parent Company is authorized to repurchase its common shares from time to time. The Parent Company’s Board of Trustees initially authorized this program in 1998 and has periodically replenished capacity under the program. On May 2, 2006, the Board of Trustees restored capacity to 3.5 million common shares.

The Parent Company did not repurchase any shares during the year-ended December 31, 2011. As of December 31, 2011, the Company may purchase an additional 0.5 million shares under the plan.

Repurchases may be made from time to time in the open market or in privately negotiated transactions, subject to market conditions and compliance with legal requirements. The share repurchase program does not contain any time limitation and does not obligate the Parent Company to repurchase any shares. The Parent Company may discontinue the program at any time.

Partners Equity of The Operating Partnership

12 Months Ended

Dec. 31, 2011

Equity [Abstract]

PARTNERS' EQUITY OF THE OPERATING PARTNERSHIP

PARTNERS’ EQUITY OF THE OPERATING PARTNERSHIP

Earnings per Common Partnership Unit

The following table details the number of units and net income used to calculate basic and diluted earnings per common partnership unit (in thousands, except unit and per unit amounts; results may not add due to rounding):



	Years ended December 31,
	2011						2010						2009
	Basic			Diluted			Basic			Diluted			Basic			Diluted
Numerator
Income (loss) from continuing operations	$	(13,232	)	$	(13,232	)	$	(31,276	)	$	(31,276	)	$	3,588		$	3,588
Net (loss) income from continuing operations attributable to non-controlling interests	—			—			—			—			(30		)	(30		)
Amount allocable to unvested restricted unitholders	(505		)	(505		)	(512		)	(512		)	(279		)	(279		)
Preferred share dividends	(7,992		)	(7,992		)	(7,992		)	(7,992		)	(7,992		)	(7,992		)
Loss from continuing operations available to common unitholders	(21,729		)	(21,729		)	(39,780		)	(39,780		)	(4,713		)	(4,713		)
Discontinued operations attributable to common unitholders	8,517			8,517			13,670			13,670			4,501			4,501
Net loss available to common unitholders	$	(13,212	)	$	(13,212	)	$	(26,110	)	$	(26,110	)	$	(212	)	$	(212	)
Denominator
Weighted-average units outstanding	145,118,841			145,118,841			137,454,796			137,454,796			114,712,869			114,712,869
Contingent securities/Stock based compensation	—			—			—			—			—			1,353,246
Total weighted-average units outstanding	145,118,841			145,118,841			137,454,796			137,454,796			114,712,869			116,066,115
Earnings (loss) per Common Share:
Loss from continuing operations attributable to common unitholders	$	(0.15	)	$	(0.15	)	$	(0.29	)	$	(0.29	)	$	(0.04	)	$	(0.04	)
Discontinued operations attributable to common unitholders	0.06			0.06			0.10			0.10			0.04			0.04
Net loss attributable to common unitholders	$	(0.09	)	$	(0.09	)	$	(0.19	)	$	(0.19	)	$	—		$	—

Unvested restricted shares are considered participating securities which require the use of the two-class method for the computation of basic and diluted earnings per share. For the years ended December 31, 2011, 2010, and 2009 earnings representing nonforfeitable dividends as noted in the table above were allocated to the unvested restricted shares.

Common Partnership Unit and Preferred Mirror Units

The Operating Partnership issues partnership units to the Parent Company in exchange for the contribution of the net proceeds of any equity security issuance by the Parent Company. The number and terms of such partnership units correspond to the number and terms of the related equity securities issued by the Parent Company. In addition, the Operating Partnership may also issue separate classes of partnership units. Historically, the Operating Partnership has had the following types of partnership units outstanding (i) Preferred Partnership Units which have been issued to parties other than the Parent Company (ii) Preferred Mirror Partnership Units which have been issued to the Parent Company and (iii) Common Partnership Units which include both interests held by the Parent Company and those held by other limited partners. Each of these interests is described in more detail below.

Preferred Mirror Partnership Units

In exchange for the proceeds received in corresponding offerings by the Parent Company of preferred shares of beneficial interest, the Operating Partnership has issued to the Parent Company a corresponding amount of Preferred Mirror Partnership Units with terms consistent with that of the preferred securities issued by the Parent Company.

On December 30, 2003, the Operating Partnership issued 2,000,000 Series D Preferred Mirror Units to the Parent Company in exchange for its contribution of the proceeds of its Series C Preferred Shares. The 2,000,000 Series D Preferred Mirror Units outstanding have an aggregate liquidation preference of $50.0 million, or $25.00 per unit. Cumulative distributions on the Series D Preferred Mirror Units are payable quarterly at an annualized rate of 7.50% of the liquidation preference. In the event that any of the Series C Preferred Shares of the Parent Company are redeemed, which may occur at the option of the Parent Company at any time on or after December 30, 2008, then an equivalent number of Series D Preferred Mirror Units will be redeemed.

On February 27, 2004, the Operating Partnership issued 2,300,000 Series E Preferred Mirror Units to the Parent Company in exchange for its contribution of the net proceeds of its Series D Preferred Shares. The 2,300,000 Series E Preferred Mirror Units outstanding have an aggregate liquidation preference of $57.5 million, or $25.00 per unit. Cumulative distributions on the Series E Preferred Mirror Units are payable quarterly at an annualized rate of 7.375% of the liquidation preference. In the event that any of the Series D Preferred Shares of the Parent Company are redeemed, which may occur at the option of the Parent Company at any time on or after February 27, 2009, then an equivalent number of Series E Preferred Mirror Units will be redeemed.

Common Partnership Units (Redeemable and General)

The Operating Partnership has two classes of Common Partnership Units: (i) Class A Limited Partnership Interest which are held by both the Parent Company and outside third parties and (iii) General Partnership Interests which are held by the Parent Company (collectively, the Class A Limited Partnership Interest, and General Partnership Interests are referred to as “Common Partnership Units”). The holders of the Common Partnership Units are entitled to share in cash distributions from, and in profits and losses of, the Operating Partnership, in proportion to their respective percentage interests, subject to preferential distributions on the preferred mirror units and the preferred units.

The Common Partnership Units held by the Parent Company (comprised of both General Partnership Units and Class A Limited Partnership Units) are presented as partner’s equity in the consolidated financial statements. Class A Limited Partnership Interest held by parties other than the Parent Company are redeemable at the option of the holder for a like number of common shares of the Parent Company, or cash, or a combination thereof, at the election of the Parent Company. Because the form of settlement of these redemption rights are not within the control of the Operating Partnership, these Common Partnership Units have been excluded from partner’s equity and are presented as redeemable limited partnership units measured at the potential cash redemption value as of the end of the periods presented based on the closing market price of the Parent Company’s common shares at December 31, 2011, 2010 and 2009, which was $9.50, $11.65, $11.40, respectively. As of December 31, 2011 and 2010, 2,698,647 and 2,791,640 of Class A Units, respectively, were outstanding and owned by outside limited partners of the Operating Partnership.

On December 13, 2011, the Operating Partnership declared a distribution of $0.15 per Class A common unit, totaling $21.5 million, which was paid on January 19, 2012 to unitholders of record as of January 5, 2012.

On December 13, 2011, the Operating Partnership declared distributions on its Series D Preferred Mirror Units and Series E Preferred Mirror Units to holders of record as of December 30, 2011. These units are entitled to a preferential return of 7.50% and 7.375%, respectively. Distributions paid on January 17, 2012 to holders of Series D Preferred Mirror Units and Series E Preferred Mirror Units totaled $0.9 million and $1.1 million, respectively.

During the year ended December 31, 2011, the Parent Company has contributed net proceeds of $8.0 million from the sale of 679,285 common shares under its Offering Program to the Operating Partnership in exchange for the issuance of 679,285 common partnership units to the Parent Company. From the inception of the Offering Program in March 2010 through December 31, 2011, the Parent Company has sold 6,421,553 shares under this program resulting in 8,578,447 remaining shares available for sale.

The Operating Partnership used the net proceeds from the sales to repay balances on its unsecured revolving credit facility and for general corporate purposes.

Common Share Repurchases

The Parent Company did not purchase any shares during the year-ended December 31, 2011 and accordingly, during the year ended December 31, 2011, the Operating Partnership did not repurchase any units in connection with the Parent Company’s share repurchase program.

Share Based Compensation, 401(k) Plan and Deferred Compensation

12 Months Ended

Dec. 31, 2011

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

SHARE BASED COMPENSATION, 401(k) PLAN AND DEFERRED COMPENSATION

Stock Options

At December 31, 2011, the Company had 3,599,672 options outstanding under its shareholder approved equity incentive plan. There were 1,311,943 options unvested as of December 31, 2011 and $2.4 million of unrecognized compensation expense associated with these options to be recognized over a weighted average period of 1.5 years. During the years ended December 31, 2011, 2010, and 2009, the Company recognized $1.4 million, $1.0 million, and $0.6 million, respectively, of compensation expense included in general and administrative expense related to unvested options. During the year ended December 31, 2011, the Company has also capitalized $0.4 million of compensation expense as part of the Company's review of employee salaries eligible for capitalization. During the years ended December 31, 2010 and 2009, the Company has capitalized nominal amounts of compensation expense.

Option activity as of December 31, 2011 and changes during the year ended December 31, 2011 were as follows:



	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value
Outstanding at January 1, 2011	3,116,611		$	14.56	7.81	$	(9,080,625	)
Granted	603,241		11.89		9.18	(1,441,746		)
Exercised	(120,180	)	2.91
Outstanding at December 31, 2011	3,599,672		$	14.50	7.20	$	(18,015,060	)
Vested/Exercisable at December 31, 2011	2,287,729		$	17.01	6.59	$	(16,912,225	)

The fair value of share option awards is estimated on the date of the grant using the Black-Scholes option valuation model. The following weighted-average assumptions were utilized in calculating the fair value of options granted during the years ended December 31, 2011 and 2010:



Grant Date	March 2, 2011		March 4, 2010
Risk-free interest rate	2.86%		3.03%
Dividend yield	5.01%		6.53%
Volatility factor	48.02%		46.89%
Weighted-average expected life	7	yrs	7	yrs



	Years ended December 31,
	2010					2009
	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in Years)	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in Years)
Outstanding at beginning of year	2,404,567		$	15.48	8.38	1,754,648		$	20.41	8.77
Granted	724,805		11.31		9.18	676,491		2.91		9.25
Forfeited/Expired	(12,761	)	2.91		—	(26,572	)	20.61		—
Outstanding at end of year	3,116,611		$	14.56	7.81	2,404,567		$	15.48	8.38
Vested/Exercisable at end of year	1,384,728		$	17.63	7.14	616,119		$	20.03	7.54

On March 2, 2011, the Compensation Committee of the Company's Board of Trustees awarded 603,241 options to the Company's executives. The options vest ratably over three years and have a ten year term. The vesting of the options is also subject to acceleration upon a change in control or if the recipient of the award were to die, become disabled, be terminated without cause or retire in a qualifying retirement prior to the vesting date. Qualifying retirement for options granted on March 2, 2011 means the recipient's voluntary termination of employment after reaching age 57 and accumulating at least 15 years of service with the Company. On May 24, 2011, the Compensation Committee modified these options in respect of 101,437 shares awarded to one of the Company's executives. The modification, with the said executive's approval, provided additional vesting conditions linked to the Company's total shareholder return, which the Company will determine every year during the vesting period. The implementation of these market conditions did not materially impact total compensation expense expected to be recognized. The modified portion of the options will vest in whole or in part only if the Company's total shareholder return achieves specified targets, subject to vesting upon death, disability, qualifying retirement or a change of control. As of December 31, 2011, none of the Company's executives had met conditions to elect a qualifying retirement.

401(k) Plan

The Company sponsors a 401(k) defined contribution plan for its employees. Each employee may contribute up to 100% of annual compensation, subject to specific limitations under the Internal Revenue Code. At its discretion, the Company can make matching contributions equal to a percentage of the employee’s elective contribution and profit sharing contributions. Effective October 1, 2011, employees automatically vest in employer contributions. The Company contributions were $0.4 million in 2011, $0.3 million in 2010 and $0.2 million in 2009.

Restricted Share Awards

As of December 31, 2011, 807,291 restricted shares were outstanding under the 1997 Plan and vest over three to seven years from the initial grant date. The remaining compensation expense to be recognized at December 31, 2011 was approximately $3.7 million. That expense is expected to be recognized over a weighted average remaining vesting period of 1.1 years. The Company recognized compensation expense related to outstanding restricted shares of $3.2 million during the year ended December 31, 2011, of which $0.7 million was capitalized as part of the Company’s review of employee salaries eligible for capitalization. For the years ended December 31, 2010 and 2009, the Company recognized $4.0 million (of which $0.9 million was capitalized) and $3.2 million (of which $0.8 million was capitalized), respectively, of compensation expense included in general and administrative expense in the respective periods related to outstanding restricted shares.

The following table summarizes the Company’s restricted share activity during the year ended December 31, 2011:



	Shares		Weighted Average Grant Date Fair value
Non-vested at January 1, 2011	851,278		$	10.75
Granted	197,035		11.92
Vested	(237,541	)	19.76
Forfeited	(3,481	)	11.47
Non-vested at December 31, 2011	807,291		$	9.46

On March 2, 2011, the Compensation Committee of the Company's Board of Trustees awarded 174,012 restricted shares to the Company's executives. The restricted shares will cliff vest after three years from the grant date. The vesting of the restricted shares is also subject to acceleration upon a change in control or if the recipient of the award were to die, become disabled, be terminated without cause or retire in a qualifying retirement prior to the vesting date. Qualifying retirement for restricted shares granted on March 2, 2011 as provided in the award agreements Plan means the recipient's voluntary termination of employment after reaching age 57 and accumulating at least 15 years of service with the Company. As of December 31, 2011, none of the Company's executives had met conditions to elect a qualifying retirement.

Restricted Performance Share Units Plan

On March 2, 2011, March 4, 2010 and April 1, 2009, the Compensation Committee of the Parent Company’s Board of Trustees awarded an aggregate of 124,293, 120,955 and 488,292 share-based awards, respectively, to its executives. These awards are referred to as Restricted Performance Share Units, or RPSUs. The RPSUs represent the right to earn common shares. The number of common shares, if any, deliverable to award recipients depends on the Company's performance based on its total return to shareholders during the three year measurement period that commenced on January 1, 2011 (in the case of the March 2, 2011 awards), January 1, 2010 (in the case of the March 4, 2010 awards) and January 1, 2009 (in the case of the April 1, 2009 awards) and that ends on the earlier of December 31, 2013, December 31, 2012 or December 31, 2011 (as applicable) or the date of a change of control, compared to the total shareholder return of REITs within an index over such respective periods. The awards are also contingent upon the continued employment of the participants through the performance periods (with exceptions for death, disability and qualifying retirement). Dividends are deemed credited to the performance units accounts and are applied to “acquire” more performance units for the account of the unit holder at the price per common share ending on the dividend payment date. If earned, awards will be settled in common shares in an amount that reflects both the number of performance units in the holder’s account at the end of the applicable measurement period and the Company’s total return to shareholders during the applicable three year measurement period relative to the total shareholder return of the REIT within the index.

If, based on an industry-based index at the end of the measurement period, the total shareholder return during the measurement period places the Company at or above a certain percentile as compared to its peers then the number of shares that will be delivered shall equal a certain percentage (not to exceed 200%) of the participant's base units. In the case of the April 1, 2009 award, a total of 372,101 shares were determined to be deliverable to award recipients on March 1, 2012. These shares, which all vested on December 31, 2011 (the end of its three year-year measurement period), were also paid cash dividends on January 19, 2012.

On the date of each grant, the awards were valued using a Monte Carlo simulation. The fair values of the 2011 and 2010 awards on the grant dates were $2.0 million, respectively, while the 2009 award was $1.1 million. The fair values of each award are being amortized over the three year cliff vesting period. In the case of the 2011 awards, the vesting of the RPSUs is also subject to acceleration upon a change in control or if the recipient of the award were to die, become disabled, terminated without cause or retire in a qualifying retirement prior to the vesting date. Qualifying retirement for restricted shares granted on March 2, 2011 as provided under the 1997 Plan means the recipient's voluntary termination of employment after reaching age 57 and accumulating at least 15 years of service with the Company. As of December 31, 2011, none of the Company's executives has met conditions to elect a qualifying retirement.

During the year ended December 31, 2011, the Company recognized total compensation expense for the 2011, 2010 and 2009 awards of $1.7 million related to this plan, of which $0.5 million was capitalized as part of the Company’s review of employee salaries eligible for capitalization. During the year ended December 31, 2010, the Company recognized total compensation expense for both the 2010 and 2009 awards of $1.0 million related to this plan, of which nominal amounts were capitalized.

Outperformance Program

On August 28, 2006, the Compensation Committee of the Parent Company’s Board of Trustees adopted a long-term incentive compensation program (the “outperformance program”) under the 1997 Plan. The outperformance program provided for share-based awards, with share issuances (if any), to take the form of both vested and restricted common shares and with any share issuances contingent upon the Company’s total shareholder return during a three year measurement period exceeding specified performance hurdles. These hurdles were not met and, accordingly, no shares were delivered under the outperformance program and the outperformance program, has terminated in accordance with its terms. The awards under the outperformance program were accounted for in accordance with the accounting standard for stock-based compensation. The aggregate grant date fair values of the awards under the outperformance program, as adjusted for estimated forfeitures, were approximately $5.9 million (with the values determined through a Monte Carlo simulation) and are being amortized into expense over the five-year vesting period beginning on the grant dates using a graded vesting attribution model. For the years ended December 31, 2011, 2010 and 2009, the Company recognized $0.1 million, $0.4 million and $0.9 million, respectively, of compensation expense related to the outperformance program. The grant date fair value is fully amortized as of December 31, 2011.

Employee Share Purchase Plan

On May 9, 2007, the Parent Company’s shareholders approved the 2007 Non-Qualified Employee Share Purchase Plan (the “ESPP”). The ESPP is intended to provide eligible employees with a convenient means to purchase common shares of the Parent Company through payroll deductions and voluntary cash purchases at an amount equal to 85% of the average closing price per share for a specified period. Under the plan document, the maximum participant contribution for the 2011 plan year is limited to the lesser of 20% of compensation or $50,000. The number of shares reserved for issuance under the ESPP is 1.25 million. During the year ended December 31, 2011, employees made purchases of $0.4 million under the ESPP and the Company recognized $0.1 million of compensation expense related to the ESPP. During the year ended December 31, 2010, employees made purchases of $0.5 million under the ESPP and the Company recognized $0.2 million of compensation expense related to the ESPP. During the year ended December 31, 2009, employees made purchases of $0.4 million under the ESPP and the Company recognized $0.3 million of compensation expense related to the ESPP. The Board of Trustees of the Parent Company may terminate the ESPP at its sole discretion at anytime.

Deferred Compensation

In January 2005, the Parent Company adopted a Deferred Compensation Plan (the “Plan”) that allows trustees and certain key employees to voluntarily defer compensation. Compensation expense is recorded for the deferred compensation and a related liability is recognized. Participants may elect designated benchmark investment options for the notional investment of their deferred compensation. The deferred compensation obligation is adjusted for deemed income or loss related to the investments selected. At the time the participants defer compensation, the Company records a liability, which is included in the Company’s consolidated balance sheet. The liability is adjusted for changes in the market value of the participants’ selected investments at the end of each accounting period, and the impact of adjusting the liability is recorded as an increase or decrease to compensation cost. For the year ended December 31, 2011, the Company recorded a nominal net decrease in compensation costs in connection with the Plan due to the change in market value of the participant investments in the Plan. For the years ended December 31, 2010 and 2009, the Company recorded a net increase in compensation costs of $1.0 million and $1.5 million, respectively, in connection with the Plan due to the change in market value of the participant investments in the Plan.

The deferred compensation obligations are unfunded, but the Company has purchased company-owned life insurance policies and mutual funds, which can be utilized as a future funding source for the Company’s obligations under the Plan. Participants in the Plan have no interest in any assets set aside by the Company to meet its obligations under the Plan. For the year ended December 31, 2011, the Company recorded a net increase in compensation costs of $0.1 million. For the years ended December 31, 2010 and 2009, the Company recorded a net reduction in compensation costs of $1.0 million and $1.8 million, respectively , in connection with the investments in the Company-owned policies and mutual funds.

Participants in the Plan may elect to have all or a portion of their deferred compensation invested in the Company’s common shares. The Company holds these shares in a rabbi trust, which is subject to the claims of the Company’s creditors in the event of the Company’s bankruptcy or insolvency. The Plan does not provide for diversification of a participant’s deferral allocated to the Company common share and deferrals allocated to Company common share can only be settled with a fixed number of shares. In accordance with the accounting standard for deferred compensation arrangements where amounts earned are held in a rabbi trust and invested, the deferred compensation obligation associated with Company’s common shares is classified as a component of shareholder’s equity and the related shares are treated as shares to be issued and are included in total shares outstanding. At December 31, 2011 and 2010, 0.3 million of such shares, respectively, were included in total shares outstanding. Subsequent changes in the fair value of the common shares are not reflected in operations or shareholders’ equity of the Company.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 64, 65, A240
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 93-6
-Paragraph 53
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 50
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5444-113901

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

+ Details

Distributions

12 Months Ended

Dec. 31, 2011

Distributions [Abstract]

DISTRIBUTIONS



	Years ended December 31,
	2011			2010			2009
Common Share Distributions:
Ordinary income	$	0.37		$	0.60		$	0.60
Capital gain	—			—			—
Non-taxable distributions	0.23			—			—
Distributions per share	$	0.60		$	0.60		$	0.60
Percentage classified as ordinary income	61.67		%	100		%	100		%
Percentage classified as capital gain	—		%	—		%	—		%
Percentage classified as non-taxable distribution	38.33		%	—		%	—		%
Preferred Share Distributions:
Total distributions declared	$	7,992,000		$	7,992,000		$	7,992,000

- Definition

The entire disclosure for shareholders' equity, comprised of portions attributable to the parent entity and noncontrolling interest, if any, including other comprehensive income (as applicable). Including, but not limited to: (1) balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings; (2) accumulated balance for each classification of other comprehensive income and total amount of comprehensive income; (3) amount and nature of changes in separate accounts, including the number of shares authorized and outstanding, number of shares issued upon exercise and conversion, and for other comprehensive income, the adjustments for reclassifications to net income; (4) rights and privileges of each class of stock authorized; (5) basis of treasury stock, if other than cost, and amounts paid and accounting treatment for treasury stock purchased significantly in excess of market; (6) dividends paid or payable per share and in the aggregate for each class of stock for each period presented; (7) dividend restrictions and accumulated preferred dividends in arrears (in aggregate and per share amount); (8) retained earnings appropriations or restrictions, such as dividend restrictions; (9) impact of change in accounting principle, initial adoption of new accounting principle and correction of an error in previously issued financial statements; (10) shares held in trust for Employee Stock Ownership Plan (ESOP); (11) deferred compensation related to issuance of capital stock; (12) note received for issuance of stock; (13) unamortized discount on shares; (14) description, terms, and number of warrants or rights outstanding; (15) shares under subscription and subscription receivables, effective date of new retained earnings after quasi-reorganization and deficit eliminated by quasi-reorganization and, for a period of at least ten years after the effective date, the point in time from which the new retained dates; and (16) retroactive effective of subsequent change in capital structure.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 4
-Section 08
-Paragraph d

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 1
-Section B
-Paragraph 7, 11A
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 3, 4, 5, 6, 7, 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Article 4

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30, 31
-Article 5

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 17: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 20: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 4.E)
-URI http://asc.fasb.org/extlink&oid=6228006&loc=d3e74512-122707

Reference 21: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 22: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29-31)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 23: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187143-122770

+ Details

Tax Credit Transactions	12 Months Ended
Tax Credit Transactions	Dec. 31, 2011
Income Tax Disclosure [Abstract]
TAX CREDIT TRANSACTIONS	TAX CREDIT TRANSACTIONS Historic Tax Credit Transaction On November 17, 2008, the Company closed a transaction with US Bancorp (“USB”) related to the historic rehabilitation of the IRS Philadelphia Campus, a 862,692 square foot office building that is 100% leased to the IRS. On August 27, 2010, the Company completed the development of the IRS Philadelphia Campus and the IRS lease commenced. USB agreed to contribute approximately $64.1 million of project costs and advanced $10.2 million of that amount contemporaneously with the closing of the transaction. USB subsequently advanced an additional $27.4 million and $23.8 million in June 2010 and December 2009, respectively. On October 19, 2011, the Company received the remaining $2.7 million of the total contributions upon its completion of certain items and compliance with the federal rehabilitation regulations. In exchange for its contributions into the development of IRS Philadelphia Campus, USB is entitled to substantially all of the benefits derived from the tax rehabilitation credits available under section 47 of the Internal Revenue Code. USB does not have a material interest in the underlying economics of the property. This transaction includes a put/call provision whereby the Company may be obligated or entitled to repurchase USB’s interest in the IRS Philadelphia Campus. The Company believes the put will be exercised and the amount attributed to that puttable non-controlling interest obligation is included in other liabilities and is being accreted to the expected fixed put price. Based on the contractual arrangements that obligate the Company to deliver tax benefits and provide other guarantees to USB and that entitle the Company through fee arrangements to receive substantially all available cash flow from the IRS Philadelphia Campus, the Company concluded that the IRS Philadelphia Campus should be consolidated. The Company also concluded that capital contributions received from USB, in substance, are consideration that the Company receives in exchange for its obligation to deliver tax credits and other tax benefits to USB. These receipts other than the amounts allocated to the put obligation will be recognized as historic tax credit transaction income in the consolidated financial statements beginning when the obligation to USB is relieved which occurs upon delivery of the expected tax benefits net of any associated costs. The tax credit is subject to 20% recapture per year beginning one year after the completion of the IRS Philadelphia Campus. The total USB contributions presented within deferred income in the Company's consolidated balance sheet amounted to to $51.6 million as of December 31, 2011 and $61.4 million as of December 31, 2010, respectively. The contributions were recorded net of the amount allocated to non-controlling interest as described above of $2.4 million and $2.1 million at December 31, 2011 and December 31, 2010, respectively. Beginning in September 2011 to September 2015, the Company recognized and will recognize the cash received as revenue net of allocated expenses over the five year credit recapture period as defined in the Internal Revenue Code within other income (expense) in its consolidated statements of operations. During the year ended December 31, 2011, the Company recognized $12.0 million of the cash received as revenue net of $0.5 million of allocated expenses within other income (expense) in its consolidated statements of operations. Direct and incremental costs incurred in structuring the transaction are deferred and will be recognized as expense in the consolidated financial statements upon the recognition of the related revenue as discussed above. The deferred costs at December 31, 2011 and 2010 are $2.1 million and $4.3 million, respectively, and are included in other assets on the Company’s consolidated balance sheet. Amounts included in interest expense related to the accretion of the non-controlling interest liability and the 2% return expected to be paid to USB on its non-controlling interest aggregate to $1.3 million, $1.1 million and $0.2 million for years ended December 31, 2011, 2010 and 2009, respectively. New Markets Tax Credit Transaction On December 30, 2008, the Company entered into a transaction with USB related to the Cira South Garage in Philadelphia, Pennsylvania and expects to receive a net benefit of $7.8 million under a qualified New Markets Tax Credit Program (“NMTC”). The NMTC was provided for in the Community Renewal Tax Relief Act of 2000 (the “Act”) and is intended to induce investment capital in underserved and impoverished areas of the United States. The Act permits taxpayers (whether companies or individuals) to claim credits against their Federal income taxes for up to 39% of qualified investments in qualified, active low-income businesses or ventures. USB contributed $13.3 million into the development of the Cira South Garage and as such it is entitled to substantially all of the benefits derived from the tax credit, but it does not have a material interest in the underlying economics of the Cira South Garage. This transaction also includes a put/call provision whereby the Company may be obligated or entitled to repurchase USB’s interest. The Company believes the put will be exercised and an amount attributed to that obligation is included in other liabilities and is being accreted to the expected fixed put price. The said put price is insignificant. Based on the contractual arrangements that obligate the Company to deliver tax benefits and provide various other guarantees to USB, the Company concluded that the investment entities established to facilitate the NMTC transaction should be consolidated. The USB contribution of $13.3 million is included in deferred income on the Company’s consolidated balance sheet at December 31, 2011 and December 31, 2010. The USB contribution other than the amount allocated to the put obligation will be recognized as income in the consolidated financial statements when the tax benefits are delivered without risk of recapture to the tax credit investors and the Company’s obligation is relieved. The Company anticipates that it will recognize the net cash received as revenue within other income/expense in the year ended December 31, 2015. The NMTC is subject to 100% recapture for a period of seven years as provided in the Internal Revenue Code. The Company expects that the put/call provision will be exercised in December 2015 when the recapture period ends. Direct and incremental costs incurred in structuring the transaction are deferred and will be recognized as expense in the consolidated financial statements upon the recognition of the related revenue as discussed above. The deferred cost at December 31, 2011 and 2010 is $5.3 million and is included in other assets on the Company’s consolidated balance sheet.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph h
-Article 4

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 136, 172
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 43, 44, 45, 46, 47, 48, 49
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319

+ Details

Accumulated Other Comprehensive Income (Loss)

12 Months Ended

Dec. 31, 2011

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)

The following table details the components of accumulated other comprehensive income (loss) of the Parent Company and the Operating Partnership as of and for the three years ended December 31, 2011 (in thousands):



Parent Company	Unrealized Gains (Losses) on Securities			Cash Flow Hedges			Accumulated Other Comprehensive Loss
Balance at January 1, 2009	$	(9	)	$	(16,996	)	$	(17,005	)
Change during year	—			7,395			7,395
Non-controlling interest — consolidated real estate venture partner’s share of unrealized (gains)/losses on derivative financial instruments	—			290			290
Ineffectiveness of forward starting swaps	—			(125		)	(125		)
Other	—			491			491
Reclassification adjustments for (gains) losses reclassified into operations	—			(184		)	(184		)
Balance at December 31, 2009	$	(9	)	$	(9,129	)	$	(9,138	)
Change during year	—			7,320			7,320
Non-controlling interest — consolidated real estate venture partner’s share of unrealized (gains)/losses on derivative financial instruments	—			(155		)	(155		)
Reclassification adjustments for (gains) losses reclassified into operations	—			28			28
Balance at December 31, 2010	$	(9	)	$	(1,936	)	$	(1,945	)
Change during year	—			(4,499		)	(4,499		)
Non-controlling interest — consolidated real estate venture partner’s share of unrealized (gains)/losses on derivative financial instruments	—			212			212
Reclassification adjustments for (gains) losses reclassified into operations	—			153			153
Balance at December 31, 2011	$	(9	)	$	(6,070	)	$	(6,079	)



Operating Partnership	Unrealized Gains (Losses) on Securities			Cash Flow Hedges			Accumulated Other Comprehensive Loss
Balance at January 1, 2009	$	(9	)	$	(16,996	)	$	(17,005	)
Change during year	—			7,395			7,395
Ineffectiveness of forward starting swaps	—			(125		)	(125		)
Other	—			491			491
Reclassification adjustments for (gains) losses reclassified into operations	—			(184		)	(184		)
Balance at December 31, 2009	$	(9	)	$	(9,419	)	$	(9,428	)
Change during year	—			7,320			7,320
Reclassification adjustments for (gains) losses reclassified into operations	—			28			28
Balance at December 31, 2010	$	(9	)	$	(2,071	)	$	(2,080	)
Change during year				(4,499		)	(4,499		)
Reclassification adjustments for (gains) losses reclassified into operations	—			153			153
Balance at December 31, 2011	$	(9	)	$	(6,417	)	$	(6,426	)

Over time, the unrealized gains and losses held in Accumulated Other Comprehensive Income (“AOCI”) will be reclassified to earnings when the related hedged items are recognized in earnings. The current balance held in AOCI is expected to be reclassified to earnings for realized losses on forecasted debt transactions over the related term of the debt obligation, as applicable.

- Definition

The entire disclosure for comprehensive income. Includes, but is not limited to, the following: 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income. Components of comprehensive income include: (1) foreign currency translation adjustments; (2) gains (losses) on foreign currency transactions that are designated as, and are effective as, economic hedges of a net investment in a foreign entity; (3) gains (losses) on intercompany foreign currency transactions that are of a long-term-investment nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements; (4) change in the market value of a futures contract that qualifies as a hedge of an asset reported at fair value; (5) unrealized holding gains (losses) on available-for-sale securities and that resulting from transfers of debt securities from the held-to-maturity category to the available-for-sale category; (6) a net loss recognized as an additional pension liability not yet recognized as net periodic pension cost; and (7) the net gain (loss) and net prior service cost or credit for pension plans and other postretirement benefit plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 130
-Paragraph 14-26
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e637-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e681-108580

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e653-108580

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e709-108580

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 55
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6920433&loc=d3e998-108581

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e640-108580

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Reclassification Adjustments
-URI http://asc.fasb.org/extlink&oid=6522872

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e716-108580

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=6920043&loc=d3e689-108580

+ Details

Segment Information

12 Months Ended

Dec. 31, 2011

Segment Reporting [Abstract]

SEGMENT INFORMATION

As of December 31, 2011, the Company manages its portfolio within seven segments: (1) Pennsylvania Suburbs, (2) Philadelphia Central Business District (CBD) (3) Metropolitan Washington D.C., (4) New Jersey/Delaware, (5) Richmond, Virginia, (6) Austin, Texas, and (7) California. The Pennsylvania Suburbs segment includes properties in Chester, Delaware, and Montgomery counties in the Philadelphia suburbs. The Philadelphia CBD segment includes properties in the City of Philadelphia, Pennsylvania. The Metropolitan Washington, D.C. segment includes properties in Northern Virginia and suburban Maryland. The New Jersey/Delaware segment includes properties in Burlington, Camden and Mercer counties and in New Castle county in the state of Delaware. The Richmond, Virginia segment includes properties primarily in Albemarle, Chesterfield, Goochland and Henrico counties and Durham, North Carolina. The Austin, Texas segment includes properties in Austin. The California segment includes properties in Oakland, Concord, Carlsbad and Rancho Bernardo. The corporate group is responsible for cash and investment management, development of certain real estate properties during the construction period, and certain other general support functions. Land held for development and construction in progress are transferred to operating properties by region upon completion of the associated construction or project.

Segment information for the three years ended December 31, 2011, 2010 and 2009 are as follows (in thousands):



	Pennsylvania Suburbs		Philadelphia CBD		Metropolitan, D.C.		New Jersey /Delaware		Richmond, Virginia		Austin, Texas		California		Corporate			Total
2011:
Real estate investments, at cost:
Operating properties	$	1,218,071	$	953,870	$	1,255,803	$	545,657	$	307,698	$	257,694	$	254,287	$	—		$	4,793,080
Construction-in-progress															25,083			$	25,083
Land inventory															109,008			$	109,008
Total revenue	158,248		125,366		128,456		81,629		36,789		30,895		21,670		(1,248		)	581,805
Property operating expenses, real estate taxes and third party management expenses	58,440		48,792		47,786		40,500		14,727		13,048		11,507		(989		)	233,811
Net operating income	$	99,808	$	76,574	$	80,670	$	41,129	$	22,062	$	17,847	$	10,163	$	(259	)	$	347,994
2010:
Real estate investments, at cost:
Operating properties	$	1,199,957	$	911,354	$	1,359,776	$	568,413	$	294,406	$	254,019	$	246,186	$	—		$	4,834,111
Construction-in-progress	—		—		—		—		—		—		—		33,322			33,322
Land inventory	—		—		—		—		—		—		—		110,055			110,055
Total revenue	152,380		92,110		137,923		87,711		36,032		32,049		22,551		(800		)	559,956
Property operating expenses, real estate taxes and third party management expenses	59,065		37,896		48,318		44,137		14,010		13,401		11,852		(1,338		)	227,341
Net operating income	$	93,315	$	54,214	$	89,605	$	43,574	$	22,022	$	18,648	$	10,699	$	538		$	332,615
2009:
Real estate investments, at cost:
Operating properties	$	1,219,391	$	490,602	$	1,372,213	$	605,181	$	301,474	$	268,806	$	254,951	$	—		$	4,512,618
Construction-in-progress	—				—		—		—		—		—		271,962			271,962
Land inventory	—				—		—		—		—		—		97,368			97,368
Total revenue	157,616		73,534		140,438		98,344		36,201		31,311		29,283		1,193			567,920
Property operating expenses, real estate taxes and third party management expenses	56,297		31,479		52,899		45,421		13,871		14,351		14,735		(1,893		)	227,160
Net operating income	$	101,319	$	42,055	$	87,539	$	52,923	$	22,330	$	16,960	$	14,548	$	3,086		$	340,760

Net operating income ("NOI") is defined as total revenue less property operating expenses, real estate taxes and third party management expenses. Segment NOI includes revenue, real estate taxes and property operating expenses directly related to operation of the properties within the respective geographical region. Segment NOI excludes property level depreciation and amortization, revenue and expenses directly associated with third party real estate management services, expenses associated with corporate administrative support services, and inter-company eliminations. NOI is the measure that is used by the Company to evaluate the operating performance of its real estate assets by segment. The Company also believes that NOI provides useful information to investors regarding its financial condition and results of operations because it reflects only those income and expenses recorded at the property level. NOI does not also reflect general and administrative expenses, interest expenses, real estate impairment losses, depreciation and amortization costs, capital expenditures and leasing costs, or trends in development and construction activities that could materially impact the Company's results from operations. All companies may not also calculate NOI in the same manner. The Company believes that net income, as defined by GAAP, is the most appropriate earnings measure.

Below is a reconciliation of consolidated net operating income to consolidated income (loss) from continuing operations:



	Year Ended December 31,
	2011			2010			2009
	(amounts in thousands)
Consolidated net operating income	$	347,994		$	332,615		$	340,760
Less:
Interest expense	(131,405		)	(132,640		)	(135,740		)
Deferred financing costs	(4,991		)	(3,770		)	(5,864		)
Depreciation and amortization	(217,680		)	(210,592		)	(203,572		)
Administrative expenses	(24,602		)	(23,306		)	(20,821		)
Recognized Hedge Activity	—			—			(916		)
Plus:
Interest income	1,813			3,222			2,499
Historic tax credit transaction income	12,026			—			—
Equity in income of real estate ventures	3,775			5,305			4,069
Net gain on sales of interests in real estate ventures	2,791			—			(3		)
Net gain on sale of undepreciated real estate	45			—			—
Loss on real estate venture formation	(222		)	—			—
Gain (loss) on early extinguishment of debt	(2,776		)	(2,110		)	23,176
Income (loss) from continuing operations	(13,232		)	(31,276		)	3,588
Income from discontinued operations	8,517			13,670			4,501
Net income (loss)	$	(4,715	)	$	(17,606	)	$	8,089

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 131
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8981-108599

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8984-108599

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9054-108599

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9031-108599

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8924-108599

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8538-108599

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8906-108599

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9038-108599

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 29
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8864-108599

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8971-108599

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 26
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8844-108599

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8380-108599

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8595-108599

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8933-108599

+ Details

Operating Leases

12 Months Ended

Dec. 31, 2011

Leases, Operating [Abstract]

OPERATING LEASES

The Company leases properties to tenants under operating leases with various expiration dates extending to 2030. Minimum future rentals on non-cancelable leases at December 31, 2011 are as follows (in thousands):



Year	Minimum Rent
2012	$	443,103
2013	424,764
2014	384,539
2015	344,641
2016	295,045
Thereafter	1,090,697

Total minimum future rentals presented above do not include amounts to be received as tenant reimbursements for operating costs.

- Definition

The entire disclosure for operating leases of a lessor. This may inlcude a general description of lessor's leasing arrangements for operating leases, including the basis on which contingent rental payments are determined, the existence and terms of renewal or purchase options and escalation clauses, restrictions imposed by lease arrangements, such as those concerning dividends, additional debt, and further leasing, rent holidays, rent concessions, or leasehold improvement incentives and unusual provisions or conditions.

+ References + Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2011

Commitments and Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

Legal Proceedings

The Company is involved from time to time in litigation on various matters, including disputes with tenants and disputes arising out of agreements to purchase or sell properties. Given the nature of the Company’s business activities, these lawsuits are considered routine to the conduct of its business. The result of any particular lawsuit cannot be predicted, because of the very nature of litigation, the litigation process and its adversarial nature, and the jury system. The Company does not expect that the liabilities, if any, that may ultimately result from such legal actions will have a material adverse effect on the consolidated financial position, results of operations or cash flows of the Company.

Letters-of-Credit

Under certain mortgages, the Company has funded required leasing and capital reserve accounts for the benefit of the mortgage lenders with letters-of-credit which totaled $1.9 million and $13.2 million at December 31, 2011 and 2010, respectively. Certain of the tenant rents at properties that secure these mortgage loans are deposited into the loan servicer’s depository accounts, which are used to fund debt service, operating expenses, capital expenditures and the escrow and reserve accounts, as necessary. Any excess cash is included in cash and cash equivalents.

Ground Rent

Future minimum rental payments under the terms of all non-cancelable ground leases under which the Company is the lessee are expensed on a straight-line basis regardless of when payments are due. The Company's ground leases have remaining lease terms ranging from 18 to 92 years. Minimum future rental payments on non-cancelable leases at December 31, 2011 are as follows (in thousands):



2012	$	1,818
2013	1,818
2014	1,818
2015	1,909
2016	1,909
Thereafter	289,440

One of the land leases provides for contingent rent participation by the lessor in certain capital transactions and net operating cash flows of the property after certain returns are achieved by the Company. Such amounts, if any, will be reflected as contingent rent when incurred. The leases also provide for payment by the Company of certain operating costs relating to the land, primarily real estate taxes. The above schedule of future minimum rental payments does not include any contingent rent amounts, nor any reimbursed expenses.

The Company acquired ground tenancy rights under a long term ground lease agreement related to its acquisition of an office building in Philadelphia, Pennsylvania on August 12, 2011. The annual rental payments under this ground lease is equal to a percentage of the NOI generated by the property. The Company has not included the amounts in the table above since such amounts are not fixed or determinable.

The Company also acquired ground tenancy rights under a long term ground lease agreement through its acquisition of Three Logan Square on August 5, 2010. The annual rental payment under this ground lease is ten dollars through August 2022 which is when the initial term of the ground lease will end. After the initial term, the Company has the option to renew the lease until 2091. The Company also has the option to purchase the land at fair market value after providing a written notice to the owner. The annual rental payment after 2022 will be adjusted at the lower of $3.0 million or the prevailing market rent at that time until 2030. Subsequent to 2030, the annual rental payment will be adjusted at the lower of $4.0 million or the prevailing market rent at the time until 2042 and at fair market value until 2091. The Company believes that based on conditions as of the date the lease was assigned (August 5, 2010), the lease will reset to market after the initial term. Using the estimated fair market rent as of the date of the acquisition over the extended term of the ground lease (assuming the purchase option is not exercised), the future payments will aggregate to $27.4 million. The Company has not included the amounts in the table above since such amounts are not fixed and determinable.

Other Commitments or Contingencies

As part of the Company’s September 2004 acquisition of a portfolio of properties from The Rubenstein Company (which the Company refers to as the TRC acquisition), the Company acquired its interest in Two Logan Square, a 708,844 square foot office building in Philadelphia, primarily through its ownership of a second and third mortgage secured by this property. This property is consolidated as the borrower is a variable interest entity and the Company, through its ownership of the second and third mortgages, is the primary beneficiary. The Company currently does not expect to take title to Two Logan Square until, at the earliest, September 2019. If the Company takes fee title to Two Logan Square upon a foreclosure of its mortgage, the Company has agreed to pay an unaffiliated third party that holds a residual interest in the fee owner of this property an amount equal to $2.9 million. On the TRC acquisition date, the Company recorded a liability of $0.7 million and this amount will accrete up to $2.9 million through September 2019. As of December 31, 2011, the Company has a balance of $1.3 million for this liability in its consolidated balance sheet.

The Company has been audited by the Internal Revenue Service (the “IRS”) for its 2004 tax year. The audit concerned the tax treatment of the TRC acquisition in September 2004 in which the Company acquired a portfolio of properties through the acquisition of a limited partnership. On December 17, 2010, the Company received notice that the IRS proposed an adjustment to the allocation of recourse liabilities allocated to the contributor of the properties. The Company has appealed the proposed adjustment. The proposed adjustment, if upheld, would not result in a material tax liability for the Company. However, an adjustment could raise a question as to whether a contributor of partnership interests in the 2004 transaction could assert a claim against the Company under the tax protection agreement entered into as part of the transaction.

As part of the Company’s 2006 merger with Prentiss Properties Trust, the 2004 TRC acquisition and several of the Company's other transactions, the Company agreed not to sell certain of the properties it acquired in transactions that would trigger taxable income to the former owners. In the case of the TRC acquisition, the Company agreed not to sell acquired properties for periods up to 15 years from the date of the TRC acquisition as follows at December 31, 2011: One Rodney Square and 130/150/170 Radnor Financial Center (January 2015); and One Logan Square, Two Logan Square and Radnor Corporate Center (January 2020). In the Prentiss acquisition, the Company assumed the obligation of Prentiss not to sell Concord Airport Plaza before March 2018. The Company’s agreements generally provide that it may dispose of the subject properties only in transactions that qualify as tax-free exchanges under Section 1031 of the Internal Revenue Code or in other tax deferred transactions. If the Company were to sell a restricted property before expiration of the restricted period in a non-exempt transaction, the Company may be required to make significant payments to the parties who sold the applicable property on account of tax liabilities attributed to them.

As part of the Company’s acquisition of properties from time to time in tax-deferred transactions, the Company has agreed to provide certain of the prior owners of the acquired properties with the right to guarantee the Company’s indebtedness. If the Company were to seek to repay the indebtedness guaranteed by the prior owner before the expiration of the applicable agreement, the Company will be required to provide the prior owner an opportunity to guaranty a qualifying replacement debt. These debt maintenance agreements may limit the Company’s ability to refinance indebtedness on terms that will be favorable to the Company.

The Company invests in its properties and regularly incurs capital expenditures in the ordinary course to maintain the properties. The Company believes that such expenditures enhance its competitiveness. The Company also enters into construction, utility and service contracts in the ordinary course of business which may extend beyond one year. These contracts typically provide for cancellation with insignificant or no cancellation penalties.

During 2008, in connection with the development of the IRS Philadelphia Campus and the Cira South Garage, the Company entered into a historic tax credit and a new market tax credit arrangement (see Note 16), respectively. The Company is required to be in compliance with various laws, regulations and contractual provisions that apply to its historic and new market tax credit arrangements. Non-compliance with applicable requirements could result in projected tax benefits not being realized and require a refund or reduction of investor capital contributions, which are reported as deferred income in the Company’s consolidated balance sheet, until such time as its obligation to deliver tax benefits is relieved. The remaining compliance periods for its tax credit arrangements runs through 2015. The Company does not anticipate that any material refunds or reductions of investor capital contributions will be required in connection with these arrangements.

- Definition

The entire disclosure for commitments and contingencies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 14
-Paragraph 3
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9, 10, 11, 12
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.25)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14435-108349

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25287-109308

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6449706&loc=d3e16207-108621

+ Details

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2011
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENT The Company has evaluated subsequent events through the date the financial statements were issued.

Summary of Quarterly Results (Unaudited)

12 Months Ended

Dec. 31, 2011

Quarterly Financial Information Disclosure [Abstract]

SUMMARY OF QUARTERLY RESULTS (UNAUDITED)

The following is a summary of quarterly financial information as of and for the years ended December 31, 2011 and 2010 (in thousands, except per share data):



	1st Quarter (a)			2nd Quarter (b)			3rd Quarter			4th Quarter
2011:
Total revenue	$	146,794		$	144,094		$	144,308		$	146,609
Net income (loss)	(490		)	(6,234		)	6,611			(4,602		)
Net income (loss) allocated to Common Shares	(439		)	(6,069		)	6,249			(4,240		)
Basic earnings (loss) per Common Share	$	(0.02	)	$	(0.06	)	$	0.03		$	(0.05	)
Diluted earnings (loss) per Common Share	$	(0.02	)	$	(0.06	)	$	0.03		$	(0.05	)
2010:
Total revenue	$	139,502		$	134,191		$	140,179		$	146,084
Net loss	(399		)	(5,600		)	(6,616		)	(4,991		)
Loss allocated to Common Shares	(348		)	(5,441		)	(6,437		)	(4,848		)
Basic loss per Common Share	$	(0.02	)	$	(0.06	)	$	(0.06	)	$	(0.05	)
Diluted loss per Common Share	$	(0.02	)	$	(0.06	)	$	(0.06	)	$	(0.05	)

(a)

During the first quarter of 2011, the Company recorded additional income of $0.5 million related to electricity charges in prior years that were under-billed to a certain tenant. This resulted in the overstatement of total revenue by $0.5 million during the current year and in the understatement of total revenue by $0.3 million and $0.2 million for the years ended December 31, 2009 and 2008, respectively. As management believes that this error was not material to prior years' consolidated financial statements and that the impact of recording the error in the current year is not material to the Company's consolidated financial statements, the Company recorded the related adjustment in the current year.

(b)

The consolidated statement of operations for the second quarter of 2011 also contained an out of period depreciation and amortization expense adjustment of $4.7 million relating to intangible assets representing tenant relationships and in-place leases that should have been written off in prior periods. This resulted in the overstatement of depreciation and amortization expense by $4.7 million million in the current year. During the year ended December 31, 2010, depreciation and amortization expense was overstated by $1.7 million and was understated by $1.4 million, $1.8 million, $1.7 million and $1.5 million during the years ended December 31, 2009, 2008, 2007, and 2006, respectively. As management believes that this error was not material to prior years' consolidated financial statements and that the impact of recording the error in the current year is not material to the Company's consolidated financial statements, the Company recorded the related adjustment during the current year.

The summation of quarterly earnings per share amounts do not necessarily equal the full year amounts. The above information was updated to reclassify amounts previously reported to reflect discontinued operations. See Note 2 and Note 10.

- Definition

The entire disclosure for the quarterly financial data in the annual financial statements. The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished.

+ References + Details

Schedule II - Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2011

Valuation and Qualifying Accounts [Abstract]

Schedule II - Valuation and Qualifying Accounts

Brandywine Realty Trust and Brandywine Operating Partnership, L.P.

Schedule II

Valuation and Qualifying Accounts

(in thousands)



Description	Balance at Beginning of Period		Additions		Deductions (1)		Balance at End of Period
Allowance for doubtful accounts:
Year ended December 31, 2011	$	15,222	$	928	$	665	$	15,485
Year ended December 31, 2010	$	16,363	$	763	$	1,904	$	15,222
Year ended December 31, 2009	$	15,474	$	2,596	$	1,707	$	16,363


(1)	Deductions represent amounts that the Company had fully reserved for in prior periods and pursuit of collection of such amounts was ceased during the period.

Schedule III - Real Estate and Accumulated Depreciation

12 Months Ended

Dec. 31, 2011

Real Estate and Accumulated Depreciation Disclosure [Abstract]

Real Estate and Accumulated Depreciation



								Gross Amount at Which Carried
				Initial Cost				December 31, 2011
Property Name	City	State	Encumberances at December 31, 2011 (a)	Land	Building and Improvements	Net Improvements (Retirements) Since Acquisition		Land	Building and Improvements	Total (b)	Accumulated Depreciation at December 31, 2011 (c)	Year of Construction	Year Acquired	Depreciable Life
PENNSYLVANIA SUBURBS
400 Berwyn Park	Berwyn	PA	—	2,657	4,462	15,031		2,657	19,493	22,150	6,742	1999	1999	40
300 Berwyn Park	Berwyn	PA	9,971	2,206	13,422	4,161		2,206	17,583	19,789	6,554	1989	1997	40
1200 Swedesford Road	Berwyn	PA	1,887	2,595	11,809	3,778		2,596	15,586	18,182	3,893	1994	2001	40
1050 Westlakes Drive	Berwyn	PA	—	2,611	10,445	5,046		2,611	15,491	18,102	5,820	1984	1999	40
200 Berwyn Park	Berwyn	PA	6,887	1,533	9,460	1,615		1,533	11,075	12,608	4,512	1987	1997	40
1180 Swedesford Road	Berwyn	PA	—	2,086	8,342	1,262		2,085	9,605	11,690	3,198	1987	2001	40
100 Berwyn Park	Berwyn	PA	5,299	1,180	7,290	2,144		1,180	9,434	10,614	3,636	1986	1997	40
1160 Swedesford Road	Berwyn	PA	—	1,781	7,124	1,071		1,781	8,195	9,976	2,690	1986	2001	40
1100 Cassett Road	Berwyn	PA	—	1,695	6,779	102		1,694	6,882	8,576	1,823	1997	2001	40
980 Harvest Drive	Blue Bell	PA	—	3,304	16,960	(808	)	3,304	16,152	19,456	5,167	1988	2002	40
925 Harvest Drive	Blue Bell	PA	—	1,671	6,606	770		1,670	7,377	9,047	2,837	1990	1998	40
920 Harvest Drive	Blue Bell	PA	—	1,209	6,595	(125	)	1,208	6,471	7,679	3,088	1990	1998	40
426 Lancaster Avenue	Devon	PA	—	1,689	6,756	405		1,688	7,162	8,850	2,884	1990	1998	40
52 Swedesford Square	East Whiteland Twp.	PA	—	4,241	16,579	557		4,241	17,136	21,377	6,341	1988	1998	40
429 Creamery Way	Exton	PA	—	1,368	5,471	451		1,368	5,922	7,290	1,667	1996	2001	40
412 Creamery Way	Exton	PA	—	1,195	4,779	1,123		1,195	5,902	7,097	1,612	1999	2001	40
440 Creamery Way	Exton	PA	—	982	3,927	1,900		982	5,827	6,809	2,124	1991	2001	40
436 Creamery Way	Exton	PA	—	994	3,978	686		994	4,664	5,658	1,251	1991	2001	40
467 Creamery Way	Exton	PA	—	906	3,623	1,070		906	4,693	5,599	1,353	1988	2001	40
100 Arrandale Boulevard	Exton	PA	—	970	3,878	274		970	4,152	5,122	1,275	1997	2001	40
457 Creamery Way	Exton	PA	—	777	3,107	1,035		777	4,142	4,919	1,062	1990	2001	40
486 Thomas Jones Way	Exton	PA	—	806	3,256	605		806	3,861	4,667	1,710	1990	1996	40
468 Thomas Jones Way	Exton	PA	—	526	2,112	612		526	2,724	3,250	972	1990	1996	40
456 Creamery Way	Exton	PA	—	635	2,548	(48	)	636	2,499	3,135	1,135	1987	1996	40
481 John Young Way	Exton	PA	—	496	1,983	14		496	1,997	2,493	540	1997	2001	40
111 Arrandale Road	Exton	PA	—	262	1,048	125		262	1,173	1,435	404	1996	2001	40
One Progress Drive	Horsham	PA	—	1,399	5,629	4,466		1,399	10,095	11,494	2,777	1986	1996	40
500 Enterprise Drive	Horsham	PA	—	1,303	5,188	3,228		1,303	8,416	9,719	2,566	1990	1996	40
640 Freedom Business Center	King Of Prussia	PA	—	4,222	16,891	2,964		4,222	19,855	24,077	7,867	1991	1998	40
555 Croton Road	King of Prussia	PA	—	4,486	17,943	1,215		4,486	19,158	23,644	5,461	1999	2001	40
630 Allendale Road	King of Prussia	PA	—	2,836	4,028	12,275		2,636	16,503	19,139	4,385	2000	2000	40
1000 First Avenue	King Of Prussia	PA	—	2,772	10,936	3,524		2,772	14,460	17,232	5,838	1980	1998	40
620 Freedom Business Center	King Of Prussia	PA	—	2,770	11,014	3,413		2,769	14,428	17,197	6,184	1986	1998	40
1060 First Avenue	King Of Prussia	PA	—	2,712	10,953	2,378		2,712	13,331	16,043	5,006	1987	1998	40
1040 First Avenue	King Of Prussia	PA	—	2,860	11,282	1,303		2,860	12,585	15,445	4,717	1985	1998	40



								Gross Amount at Which Carried
				Initial Cost				December 31, 2011
Property Name	City	State	Encumberances at December 31, 2011 (a)	Land	Building and Improvements	Net Improvements (Retirements) Since Acquisition		Land	Building and Improvements	Total (b)	Accumulated Depreciation at December 31, 2011 (c)	Year of Construction	Year Acquired	Depreciable Life
630 Freedom Business Center	King Of Prussia	PA	—	2,773	11,144	1,199		2,773	12,343	15,116	4,910	1989	1998	40
1020 First Avenue	King Of Prussia	PA	—	2,168	8,576	4,117		2,168	12,693	14,861	5,079	1984	1998	40
610 Freedom Business Center	King Of Prussia	PA	—	2,017	8,070	1,195		2,017	9,265	11,282	3,546	1985	1998	40
500 North Gulph Road	King Of Prussia	PA	—	1,303	5,201	1,834		1,303	7,035	8,338	2,988	1979	1996	40
650 Park Avenue	King Of Prussia	PA	—	1,916	4,378	2,042		1,917	6,419	8,336	2,819	1968	1998	40
741 First Avenue	King Of Prussia	PA	—	1,287	5,151	12		1,288	5,162	6,450	1,996	1966	1998	40
875 First Avenue	King Of Prussia	PA	—	618	2,473	3,239		618	5,712	6,330	2,438	1966	1998	40
751-761 Fifth Avenue	King Of Prussia	PA	—	1,097	4,391	31		1,097	4,422	5,519	1,712	1967	1998	40
600 Park Avenue	King Of Prussia	PA	—	1,012	4,048	385		1,012	4,433	5,445	1,684	1964	1998	40
620 Allendale Road	King Of Prussia	PA	—	1,020	3,839	503		1,020	4,342	5,362	1,645	1961	1998	40
660 Allendale Road	King Of Prussia	PA	—	396	948	2,505		1,085	2,764	3,849	42	2011	1998	40
640 Allendale Road	King of Prussia	PA	—	439	432	1,553		439	1,985	2,424	564	2000	2000	40
101 Lindenwood Drive	Malvern	PA	—	4,152	16,606	3,331		4,152	19,937	24,089	4,954	1988	2001	40
301 Lindenwood Drive	Malvern	PA	—	2,729	10,915	1,264		2,729	12,179	14,908	3,541	1984	2001	40
300 Lindenwood Drive	Malvern	PA	—	848	3,394	1,334		849	4,727	5,576	1,532	1991	2001	40
1700 Paoli Pike	Malvern	PA	—	458	559	3,018		488	3,547	4,035	977	2000	2000	40
100 Lindenwood Drive	Malvern	PA	—	473	1,892	188		474	2,079	2,553	575	1985	2001	40
200 Lindenwood Drive	Malvern	PA	—	324	1,295	335		324	1,630	1,954	378	1984	2001	40
14 Campus Boulevard	Newtown Square	PA	6,384	2,244	4,217	1,515		2,243	5,733	7,976	2,311	1998	1998	40
11 Campus Boulevard	Newtown Square	PA	4,379	1,112	4,067	1,047		1,112	5,114	6,226	1,836	1998	1999	40
17 Campus Boulevard	Newtown Square	PA	4,458	1,108	5,155	(397	)	1,108	4,758	5,866	1,098	2001	N/A	40
15 Campus Boulevard	Newtown Square	PA	4,555	1,164	3,896	229		1,164	4,125	5,289	1,016	2002	N/A	40
18 Campus Boulevard	Newtown Square	PA	3,431	787	3,312	313		787	3,625	4,412	1,780	1990	1996	40
401 Plymouth Road	Plymouth Meeting	PA	—	6,198	16,131	15,959		6,199	32,089	38,288	8,130	2001	N/A	40
4000 Chemical Road	Plymouth Meeting	PA	—	4,373	24,546	4,509		4,373	29,055	33,428	4,005	2006	N/A	40
610 West Germantown Pike	Plymouth Meeting	PA	—	3,651	14,514	3,017		3,651	17,531	21,182	4,595	1987	2002	40
600 West Germantown Pike	Plymouth Meeting	PA	—	3,652	15,288	1,958		3,652	17,246	20,898	4,225	1986	2002	40
630 West Germantown Pike	Plymouth Meeting	PA	—	3,558	14,743	2,199		3,558	16,942	20,500	4,585	1988	2002	40
620 West Germantown Pike	Plymouth Meeting	PA	—	3,572	14,435	1,220		3,572	15,655	19,227	3,921	1990	2002	40
2240/2250 Butler Pike	Plymouth Meeting	PA	—	1,104	4,627	1,277		1,104	5,904	7,008	2,929	1984	1996	40
2260 Butler Pike	Plymouth Meeting	PA	—	661	2,727	1,198		662	3,924	4,586	1,710	1984	1996	40
120 West Germantown Pike	Plymouth Meeting	PA	—	685	2,773	631		685	3,404	4,089	1,481	1984	1996	40
140 West Germantown Pike	Plymouth Meeting	PA	—	481	1,976	318		481	2,294	2,775	1,096	1984	1996	40
351 Plymouth Road	Plymouth Meeting	PA	—	1,043	555	—		1,043	555	1,598	94	N/A	2000	40
150 Radnor Chester Road	Radnor	PA	—	11,925	36,986	12,838		11,897	49,852	61,749	12,855	1983	2004	29
One Radnor Corporate Center	Radnor	PA	—	7,323	28,613	22,241		7,323	50,854	58,177	10,296	1998	2004	29
201 King of Prussia Road	Radnor	PA	—	8,956	29,811	6,700		8,949	36,518	45,467	11,783	2001	2004	25



								Gross Amount at Which Carried
				Initial Cost				December 31, 2011
Property Name	City	State	Encumberances at December 31, 2011 (a)	Land	Building and Improvements	Net Improvements (Retirements) Since Acquisition		Land	Building and Improvements	Total (b)	Accumulated Depreciation at December 31, 2011 (c)	Year of Construction	Year Acquired	Depreciable Life
555 Lancaster Avenue	Radnor	PA	—	8,014	16,508	18,711		8,609	34,624	43,233	9,207	1973	2004	24
Four Radnor Corporate Center	Radnor	PA	—	5,406	21,390	11,350		5,705	32,441	38,146	9,291	1995	2004	30
Five Radnor Corporate Center	Radnor	PA	—	6,506	25,525	2,159		6,578	27,612	34,190	6,414	1998	2004	38
Three Radnor Corporate Center	Radnor	PA	—	4,773	17,961	2,361		4,792	20,303	25,095	5,259	1998	2004	29
Two Radnor Corporate Center	Radnor	PA	—	3,937	15,484	1,208		3,942	16,687	20,629	4,396	1998	2004	29
130 Radnor Chester Road	Radnor	PA	—	2,573	8,338	3,542		2,568	11,885	14,453	2,788	1983	2004	25
170 Radnor Chester Road	Radnor	PA	—	2,514	8,147	3,283		2,508	11,436	13,944	3,203	1983	2004	25
101 West Elm Street	W. Conshohocken	PA	—	6,251	25,209	3,010		6,252	28,218	34,470	4,845	1999	2005	40
1 West Elm Street	W. Conshohocken	PA	—	3,557	14,249	1,128		3,557	15,377	18,934	2,497	1999	2005	40
595 East Swedesford Road	Wayne	PA	—	2,729	10,917	2,072		2,729	12,989	15,718	2,939	1998	2003	40
575 East Swedesford Road	Wayne	PA	—	2,178	8,712	1,630		2,178	10,342	12,520	2,551	1985	2003	40
565 East Swedesford Road	Wayne	PA	—	1,872	7,489	1,785		1,872	9,274	11,146	2,208	1984	2003	40
585 East Swedesford Road	Wayne	PA	—	1,350	5,401	358		1,351	5,758	7,109	1,325	1998	2003	40
1336 Enterprise Drive	West Goshen	PA	—	731	2,946	47		731	2,993	3,724	1,275	1989	1997	40
PHILADELPHIA CBD
2970 Market Street	Philadelphia	PA	202,905	22,430	217,763	9,956		22,430	227,719	250,149	8,408	2010	2007	40
2929 Arch Street	Philadelphia	PA	—	—	208,570	18,366		—	226,936	226,936	55,716	2005	N/A	40
130 North 18th Street	Philadelphia	PA	—	14,496	107,736	10,054		14,473	117,813	132,286	28,639	1998	2004	23
100 North 18th Street	Philadelphia	PA	89,800	16,066	100,255	5,671		16,066	105,926	121,992	26,011	1988	2004	33
1717 Arch Street	Philadelphia	PA	—	—	98,188	3,346		—	101,534	101,534	7,383	1990	2010	40
2930 Chestnut Street	Philadelphia	PA	44,379	—	76,008	3,064		—	79,072	79,072	2,600	2010	N/A	40
3020 Market Street	Philadelphia	PA	—	—	21,417	20		—	21,437	21,437	277	1959	2011	26
101 - 103 Juniper Street	Philadelphia	PA	—	—	14,401	76		—	14,477	14,477	212	2010	2006	40
Philadelphia Marine Center	Philadelphia	PA	—	532	2,196	3,236		628	5,336	5,964	1,749	Various	1998	40
METROPOLITAN WASHINGTON, D.C.
11720 Beltsville Drive	Beltsville	MD	—	3,831	16,661	4,047		3,903	20,636	24,539	4,357	1987	2006	46
11700 Beltsville Drive	Beltsville	MD	—	2,808	12,081	339		2,863	12,365	15,228	2,033	1981	2006	46
11710 Beltsville Drive	Beltsville	MD	—	2,278	11,100	(769	)	2,322	10,288	12,610	1,578	1987	2006	46
6600 Rockledge Drive	Bethesda	MD	—	—	37,421	11,145		—	48,566	48,566	8,529	1981	2006	50
11740 Beltsville Drive	Bethesda	MD	—	198	870	42		203	908	1,111	146	1987	2006	46
12015 Lee Jackson Memorial Highway	Fairfax	VA	—	3,770	22,895	2,702		3,841	25,526	29,367	3,937	1985	2006	42
11781 Lee Jackson Memorial Highway	Fairfax	VA	—	3,246	19,836	(289	)	3,307	19,487	22,794	3,572	1982	2006	40
4401 Fair Lakes Court	Fairfax	VA	—	1,569	11,982	284		1,600	12,236	13,836	1,738	1988	2006	52
3141 Fairview Park Drive (d)	Falls Church	VA	22,000	5,918	40,981	8,917		7,081	48,736	55,817	6,499	1988	2006	51



								Gross Amount at Which Carried
				Initial Cost				December 31, 2011
Property Name	City	State	Encumberances at December 31, 2011 (a)	Land	Building and Improvements	Net Improvements (Retirements) Since Acquisition		Land	Building and Improvements	Total (b)	Accumulated Depreciation at December 31, 2011 (c)	Year of Construction	Year Acquired	Depreciable Life
2340 Dulles Corner Boulevard	Herndon	VA	—	16,345	65,379	18,370		16,129	83,965	100,094	17,616	1987	2006	40
13820 Sunrise Valley Drive	Herndon	VA	—	11,082	47,290	19,687		11,082	66,977	78,059	8,334	2007	N/A	40
2291 Wood Oak Drive	Herndon	VA	—	8,243	52,413	12,805		8,781	64,680	73,461	6,930	1999	2006	55
2355 Dulles Corner Boulevard	Herndon	VA	—	10,365	43,876	4,418		10,364	48,295	58,659	7,804	1988	2006	40
196/198 Van Buren Street	Herndon	VA	—	7,931	43,812	6,058		8,348	49,453	57,801	7,660	1991	2006	53
2251 Corporate Park Drive	Herndon	VA	—	11,472	45,893	337		11,471	46,231	57,702	5,942	2000	2006	40
2411 Dulles Corner Park	Herndon	VA	—	7,279	46,340	3,691		7,416	49,894	57,310	7,736	1990	2006	50
2121 Cooperative Way	Herndon	VA	—	5,598	38,639	1,330		5,794	39,772	45,566	4,593	2000	2006	54
13880 Dulles Corner Lane	Herndon	VA	—	7,236	39,213	(1,132	)	7,373	37,943	45,316	4,816	1997	2006	55
2201 Cooperative Way	Herndon	VA	—	4,809	34,093	(678	)	4,809	33,416	38,225	3,936	1990	2006	54
13825 Sunrise Valley Drive	Herndon	VA	—	3,794	19,365	(851	)	3,865	18,443	22,308	2,480	1989	2006	46
1676 International Drive	Mclean	VA	61,976	18,437	97,538	1,650		18,785	98,840	117,625	13,100	1999	2006	55
8260 Greensboro Drive	Mclean	VA	32,906	7,952	33,964	242		8,103	34,055	42,158	4,509	1980	2006	52
1880 Campus Commons Drive	Reston	VA	—	6,164	28,114	1,714		6,281	29,711	35,992	3,636	1985	2006	52
2273 Research Boulevard	Rockville	MD	—	5,167	31,110	3,179		5,237	34,219	39,456	6,197	1999	2006	45
2275 Research Boulevard	Rockville	MD	—	5,059	29,668	2,372		5,154	31,945	37,099	5,358	1990	2006	45
2277 Research Boulevard	Rockville	MD	—	4,649	26,952	823		4,733	27,690	32,423	4,304	1986	2006	45
1900 Gallows Road	Vienna	VA	—	7,797	47,817	2,978		7,944	50,648	58,592	6,300	1989	2006	52
8521 Leesburg Pike	Vienna	VA	—	4,316	30,885	(1,004	)	4,397	29,799	34,196	4,022	1984	2006	51
NEW JERSEY/DELAWARE
457 Haddonfield Road	Cherry Hill	NJ	11,175	2,142	9,120	853		2,142	9,973	12,115	4,138	1990	1996	40
220 Lake Drive East	Cherry Hill	NJ	—	2,144	8,798	863		2,144	9,661	11,805	2,799	1988	2001	40
200 Lake Drive East	Cherry Hill	NJ	—	2,069	8,275	1,244		2,068	9,520	11,588	2,559	1989	2001	40
210 Lake Drive East	Cherry Hill	NJ	—	1,645	6,579	1,332		1,645	7,911	9,556	2,222	1986	2001	40
6 East Clementon Road	Gibbsboro	NJ	—	1,345	5,366	682		1,345	6,048	7,393	2,303	1980	1997	40
20 East Clementon Road	Gibbsboro	NJ	—	769	3,055	582		768	3,638	4,406	1,425	1986	1997	40
10 Foster Avenue	Gibbsboro	NJ	—	244	971	118		244	1,089	1,333	450	1983	1997	40
7 Foster Avenue	Gibbsboro	NJ	—	231	921	16		231	937	1,168	373	1983	1997	40
50 East Clementon Road	Gibbsboro	NJ	—	114	964	3		114	967	1,081	383	1986	1997	40
2 Foster Avenue	Gibbsboro	NJ	—	185	730	16		185	746	931	297	1974	1997	40
4 Foster Avenue	Gibbsboro	NJ	—	183	726	5		182	732	914	290	1974	1997	40
1 Foster Avenue	Gibbsboro	NJ	—	93	364	76		93	440	533	185	1972	1997	40
5 U.S. Avenue	Gibbsboro	NJ	—	21	81	3		21	84	105	33	1987	1997	40
5 Foster Avenue	Gibbsboro	NJ	—	9	32	26		9	58	67	23	1968	1997	40



								Gross Amount at Which Carried
				Initial Cost				December 31, 2011
Property Name	City	State	Encumberances at December 31, 2011 (a)	Land	Building and Improvements	Net Improvements (Retirements) Since Acquisition		Land	Building and Improvements	Total (b)	Accumulated Depreciation at December 31, 2011 (c)	Year of Construction	Year Acquired	Depreciable Life
1009 Lenox Drive	Lawrenceville	NJ	—	4,876	19,284	4,373		5,118	23,415	28,533	9,039	1989	1998	40
989 Lenox Drive	Lawrenceville	NJ	—	3,701	14,802	1,420		3,850	16,073	19,923	3,610	1984	2003	40
997 Lenox Drive	Lawrenceville	NJ	—	2,410	9,700	4,442		2,540	14,012	16,552	4,781	1987	1998	40
2000 Lenox Drive	Lawrenceville	NJ	—	2,291	12,221	1,975		2,684	13,803	16,487	3,499	2000	2000	40
993 Lenox Drive	Lawrenceville	NJ	—	2,811	17,996	(4,369	)	2,960	13,478	16,438	5,196	1985	1998	40
1200 Lenox Drive	Lawrenceville	NJ	—	1,071	12,967	1,238		1,071	14,205	15,276	1,846	2007	N/A	40
100 Lenox Drive	Lawrenceville	NJ	—	—	—	12,103		1,134	10,969	12,103	1,815	1977	1999	40
1000 Lenox Drive	Lawrenceville	NJ	—	1,174	4,696	2,180		1,244	6,806	8,050	2,677	1982	2002	40
1120 Executive Boulevard	Marlton	NJ	—	2,074	8,415	1,804		2,074	10,219	12,293	4,200	1987	1997	40
Two Eves Drive	Marlton	NJ	—	818	3,461	178		819	3,638	4,457	1,575	1987	1997	40
Five Eves Drive	Marlton	NJ	—	703	2,819	511		703	3,330	4,033	1,392	1986	1997	40
Four B Eves Drive	Marlton	NJ	—	588	2,369	361		589	2,729	3,318	1,180	1987	1997	40
Four A Eves Drive	Marlton	NJ	—	539	2,168	136		538	2,305	2,843	1,011	1987	1997	40
308 Harper Drive	Moorestown	NJ	—	1,643	6,663	1,070		1,644	7,732	9,376	2,685	1976	1998	40
304 Harper Drive	Moorestown	NJ	—	657	2,674	359		657	3,033	3,690	1,161	1975	1998	40
700 East Gate Drive	Mt. Laurel	NJ	—	3,569	14,436	2,122		3,568	16,559	20,127	6,205	1984	1998	40
10000 Midlantic Drive	Mt. Laurel	NJ	—	3,206	12,857	1,473		3,206	14,330	17,536	6,306	1990	1997	40
15000 Midlantic Drive	Mt. Laurel	NJ	—	3,061	12,254	1,070		3,061	13,324	16,385	5,351	1991	1997	40
1000 Atrium Way	Mt. Laurel	NJ	—	2,061	8,180	3,583		2,062	11,762	13,824	4,788	1989	1997	40
1000 Howard Boulevard	Mt. Laurel	NJ	—	2,297	9,288	1,378		2,297	10,666	12,963	4,294	1988	1997	40
2000 Midlantic Drive	Mt. Laurel	NJ	—	2,202	8,823	1,905		2,203	10,727	12,930	3,953	1989	1997	40
701 East Gate Drive	Mt. Laurel	NJ	—	1,736	6,877	1,277		1,736	8,154	9,890	2,843	1986	1998	40
307 Fellowship Drive	Mt. Laurel	NJ	—	1,565	6,342	1,295		1,564	7,638	9,202	2,658	1981	1998	40
9000 Midlantic Drive	Mt. Laurel	NJ	—	1,472	5,895	1,785		1,471	7,681	9,152	2,608	1989	1997	40
305 Fellowship Drive	Mt. Laurel	NJ	—	1,421	5,768	1,440		1,421	7,208	8,629	3,050	1980	1998	40
309 Fellowship Drive	Mt. Laurel	NJ	—	1,518	6,154	564		1,518	6,718	8,236	2,472	1982	1998	40
303 Fellowship Drive	Mt. Laurel	NJ	—	1,493	6,055	567		1,493	6,622	8,115	2,441	1979	1998	40
1000 Bishops Gate	Mt. Laurel	NJ	—	934	6,287	427		934	6,714	7,648	1,755	2005	2000	40
161 Gaither Drive	Mt. Laurel	NJ	—	1,016	4,064	818		1,016	4,882	5,898	1,578	1987	2001	40
4000 Midlantic Drive	Mt. Laurel	NJ	—	714	5,085	(1,403	)	714	3,682	4,396	1,810	1998	1997	40
815 East Gate Drive	Mt. Laurel	NJ	—	636	2,584	253		636	2,837	3,473	1,092	1986	1998	40
817 East Gate Drive	Mt. Laurel	NJ	—	611	2,426	360		612	2,785	3,397	1,096	1986	1998	40
400 Commerce Drive	Newark	DE	—	2,528	9,220	1,180		2,528	10,400	12,928	3,000	1997	2002	40
200 Commerce Drive	Newark	DE	—	911	4,414	1,018		911	5,432	6,343	1,676	1998	2002	40
100 Commerce Drive	Newark	DE	—	1,160	4,633	454		1,159	5,088	6,247	2,116	1989	1997	40



							Gross Amount at Which Carried
				Initial Cost			December 31, 2011
Property Name	City	State	Encumberances at December 31, 2011 (a)	Land	Building and Improvements	Net Improvements (Retirements) Since Acquisition	Land	Building and Improvements	Total (b)	Accumulated Depreciation at December 31, 2011 (c)	Year of Construction	Year Acquired	Depreciable Life
Main Street - Plaza 1000	Voorhees	NJ	—	2,732	10,942	3,446	2,732	14,388	17,120	6,143	1988	1997	40
Main Street - Piazza	Voorhees	NJ	—	696	2,802	60	696	2,862	3,558	1,233	1990	1997	40
Main Street - Promenade	Voorhees	NJ	—	531	2,052	363	531	2,415	2,946	916	1988	1997	40
920 North King Street	Wilmington	DE	—	6,141	21,140	1,232	6,142	22,371	28,513	6,432	1989	2004	30
300 Delaware Avenue	Wilmington	DE	—	6,368	13,739	2,942	6,369	16,680	23,049	5,121	1989	2004	23
Two Righter Parkway	Wilmington	DE	—	2,802	11,217	5,255	2,803	16,471	19,274	2,361	1987	2001	40
One Righter Parkway	Wilmington	DE	—	2,545	10,195	4,773	2,546	14,967	17,513	7,070	1989	1996	40
RICHMOND
4364 South Alston Avenue	Durham	NC	—	1,622	6,419	892	1,580	7,353	8,933	2,625	1985	1998	40
4805 Lake Brooke Drive	Glen Allen	VA	—	1,640	6,567	1,373	1,640	7,940	9,580	3,220	1996	1998	40
Overlook II	Glen Allen	VA	—	791	4,503	62	790	4,565	5,355	188	2000	2011	40
Overlook I	Glen Allen	VA	—	791	3,976	93	790	4,069	4,859	181	1998	2011	40
2812 Emerywood Parkway	Henrico	VA	—	1,069	4,281	1,043	1,069	5,324	6,393	2,226	1980	1998	40
300 Arboretum Place	Richmond	VA	—	5,450	21,892	3,528	5,450	25,420	30,870	9,639	1988	1998	40
7501 Boulders View Drive	Richmond	VA	—	4,669	19,699	1,952	4,925	21,395	26,320	2,510	1990	2007	40
7300 Beaufont Springs Drive	Richmond	VA	—	4,672	19,689	670	4,922	20,109	25,031	2,256	2000	2007	40
6800 Paragon Place	Richmond	VA	—	4,552	18,414	1,549	4,552	19,963	24,515	3,110	1986	2006	40
6802 Paragon Place	Richmond	VA	—	2,917	11,454	2,469	2,917	13,923	16,840	3,638	1989	2002	40
1025 Boulders Parkway	Richmond	VA	—	2,574	11,297	1,146	2,825	12,192	15,017	1,364	1994	2007	40
2100-2116 West Laburnam Avenue	Richmond	VA	—	2,482	8,846	3,073	2,482	11,919	14,401	4,497	1976	1998	40
7401 Beaufont Springs Drive	Richmond	VA	—	2,349	10,396	717	2,599	10,863	13,462	1,201	1998	2007	40
7325 Beaufont Springs Drive	Richmond	VA	—	2,344	10,377	502	2,594	10,629	13,223	1,307	1999	2007	40
6806 Paragon Place	Richmond	VA	—	—	10,288	827	403	10,712	11,115	2,573	2007	2005	40
9011 Arboretum Parkway	Richmond	VA	—	1,857	7,702	832	1,856	8,535	10,391	3,333	1991	1998	40
2511 Brittons Hill Road	Richmond	VA	—	1,202	4,820	1,472	1,202	6,292	7,494	2,472	1987	1998	40
9100 Arboretum Parkway	Richmond	VA	—	1,362	5,489	565	1,362	6,054	7,416	2,298	1988	1998	40
100 Gateway Centre Parkway	Richmond	VA	—	391	5,410	885	391	6,295	6,686	1,878	2001	1998	40
9200 Arboretum Parkway	Richmond	VA	—	985	3,973	1,353	984	5,327	6,311	1,819	1988	1998	40
9210 Arboretum Parkway	Richmond	VA	—	1,110	4,474	486	1,110	4,960	6,070	1,839	1988	1998	40
2201-2245 Tomlynn Street	Richmond	VA	—	1,020	4,067	447	1,019	4,515	5,534	1,620	1989	1998	40
9211 Arboretum Parkway	Richmond	VA	—	582	2,433	252	582	2,685	3,267	1,048	1991	1998	40
2212-2224 Tomlynn Street	Richmond	VA	—	502	2,014	353	502	2,367	2,869	779	1985	1998	40
2244 Dabney Road	Richmond	VA	—	550	2,203	37	550	2,240	2,790	837	1993	1998	40
2248 Dabney Road	Richmond	VA	—	512	2,049	223	512	2,272	2,784	854	1989	1998	40
2221-2245 Dabney Road	Richmond	VA	—	530	2,123	80	529	2,204	2,733	804	1994	1998	40
2277 Dabney Road	Richmond	VA	—	507	2,034	61	507	2,095	2,602	751	1986	1998	40
2246 Dabney Road	Richmond	VA	—	455	1,822	18	455	1,840	2,295	682	1987	1998	40



												Gross Amount at Which Carried
					Initial Cost							December 31, 2011
Property Name	City	State	Encumberances at December 31, 2011 (a)		Land		Building and Improvements		Net Improvements (Retirements) Since Acquisition			Land		Building and Improvements		Total (b)		Accumulated Depreciation at December 31, 2011 (c)		Year of Construction	Year Acquired	Depreciable Life
2161-2179 Tomlynn Street	Richmond	VA	—		423		1,695		68			423		1,763		2,186		640		1985	1998	40
2251 Dabney Road	Richmond	VA	—		387		1,552		138			387		1,690		2,077		636		1983	1998	40
2256 Dabney Road	Richmond	VA	—		356		1,427		273			356		1,700		2,056		676		1982	1998	40
2130-2146 Tomlynn Street	Richmond	VA	—		353		1,416		213			353		1,629		1,982		681		1988	1998	40
2120 Tomlynn Street	Richmond	VA	—		281		1,125		204			280		1,330		1,610		475		1986	1998	40
2240 Dabney Road	Richmond	VA	—		264		1,059		11			264		1,069		1,333		396		1984	1998	40
Boulders Land	Richmond	VA	—		1,256		—		3			1,259		—		1,259		—		N/A	2007	N/A
CALIFORNIA
5780 & 5790 Fleet Street	Carlsbad	CA	—		7,073		22,907		3,435			7,516		25,899		33,415		3,596		1999	2006	55
5900 & 5950 La Place Court	Carlsbad	CA	—		3,706		11,185		2,090			3,955		13,026		16,981		2,090		1988	2006	48
5963 La Place Court	Carlsbad	CA	—		2,824		9,413		1,662			2,999		10,900		13,899		1,647		1987	2006	55
5973 Avenida Encinas	Carlsbad	CA	—		2,121		8,361		1,383			2,256		9,609		11,865		1,803		1986	2006	45
2035 Corte Del Nogal	Carlsbad	CA	—		3,261		6,077		1,250			3,499		7,089		10,588		1,484		1991	2006	39
1200 Concord Avenue	Concord	CA	—		6,395		24,664		235			6,515		24,778		31,293		4,215		1984	2006	34
1220 Concord Avenue	Concord	CA	—		6,476		24,966		(332		)	6,476		24,634		31,110		3,911		1984	2006	34
155 Grand Avenue	Oakland	CA	—		13,556		54,266		4,482			13,555		58,749		72,304		7,863		1990	2007	40
Two Kaiser Plaza	Oakland	CA	—		7,841		—		—			7,841		—		7,841		—		N/A	2006	N/A
Oakland Lot B	Oakland	CA	—		4,342		—		—			4,342		—		4,342		—		N/A	2006	N/A
16870 W Bernardo Drive	San Diego	CA	—		2,979		15,896		1,766			3,154		17,487		20,641		2,562		2002	2006	56
AUSTIN
1250 Capital of Texas Hwy South	Austin	TX	—		5,152		37,928		5,826			5,247		43,659		48,906		7,063		1984	2006	52
1301 Mopac Expressway	Austin	TX	—		4,188		41,229		(595		)	4,251		40,571		44,822		5,732		2001	2006	55
1221 Mopac Expressway	Austin	TX	—		3,290		31,548		4,228			3,369		35,696		39,065		3,900		2001	2006	55
1601 Mopac Expressway	Austin	TX	—		3,538		34,346		220			3,605		34,499		38,104		4,390		2000	2006	54
1501 South Mopac Expressway	Austin	TX	—		3,698		34,912		(2,202		)	3,767		32,640		36,407		3,889		1999	2006	53
3711 South Mopac Expressway - II	Austin	TX	—		1,688		19,229		4,316			1,688		23,545		25,233		3,660		2007	2006	40
3711 South Mopac Expressway - I	Austin	TX	—		1,688		21,011		2,451			1,688		23,462		25,150		2,262		2007	2006	40
	Total:		$	512,391	$	666,690	$	3,603,754	$	522,640		$	677,891	$	4,115,189	$	4,793,080	$	865,710


(a)	Excludes the effect of any net interest premium/(discount).


(b)	Reconciliation of Real Estate:

The following table reconciles the real estate investments from January 1, 2009 to December 31, 2011 (in thousands):



	2011			2010			2009
Balance at beginning of year	$	4,834,111		$	4,512,618		$	4,608,320
Additions:
Acquisitions	31,454			102,475			—
Capital expenditures	133,550			336,281			80,506
Less:
Dispositions	(206,035		)	(117,263		)	(176,208		)
Balance at end of year	$	4,793,080		$	4,834,111		$	4,512,618

The aggregate cost for federal income tax purposes is $4.5 billion as of December 31, 2011


(c)	Reconciliation of Accumulated Depreciation:

The following table reconciles the accumulated depreciation on real estate investments from January 1, 2009 to December 31, 2011 (in thousands):



	2011			2010			2009
Balance at beginning of year	$	776,078		$	716,957		$	639,688
Additions:
Depreciation expense — continuing operations	157,691			133,740			141,309
Depreciation expense — discontinued operations	1,185			1,554			6,494
Less:
Dispositions	(69,244		)	(76,173		)	(70,534		)
Balance at end of year	$	865,710		$	776,078		$	716,957

(d) This property was contributed to an unconsolidated real estate venture, however, the Company will continue to consolidate this property due to its continuing involvement in this property resulting from its ongoing lease at this property and its 50% ownership interest in the venture. Please see Note 3 to the consolidated financial financial statements for additional information.

- Definition

The entire disclosure for real estate and accumulated depreciation. This may include a schedule that describes the property and lists the initial cost of land, buildings and improvements, improvements and carrying costs capitalized after acquisition, and the total carrying cost for land, buildings and improvements for each property and in aggregate. The schedule also lists the accumulated depreciation for each property and in aggregate, the date each property was constructed and acquired, the useful life used to calculate depreciation and any encumbrances on the properties. The entity provides a reconciliation of the carrying amount of real estate from the beginning of the period to the end of the period. Any real estate investments that have been written down or reserved against are described, including the basis of the write-down. A material amount of intercompany profit in the total carrying amount of real estate is disclosed. The aggregate cost of all real estate investments for federal income tax purposes is also disclosed.

+ References + Details

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2011

Accounting Policies [Abstract]

Principles of Consolidation

Also, for all entities determined to be VIEs, the Company does not provide financial support to the real estate ventures through liquidity arrangements, guarantees or other similar commitments. When an entity is not deemed to be a VIE, the Company considers the provisions of the same accounting standard to determine whether a general partner, or the general partners as a group, controls a limited partnership or similar entity when the limited partners have certain rights. The Company consolidates (i) entities that are VIEs and of which the Company is deemed to be the primary beneficiary and (ii) entities that are non-VIEs and controlled by the Company and in which the limited partners neither have the ability to dissolve the entity or remove the Company without cause nor any substantive participating rights. Entities that the Company accounts for under the equity method (i.e., at cost, increased or decreased by the Company's share of earnings or losses, plus contributions, less distributions) include (i) entities that are VIEs and of which the Company is not deemed to be the primary beneficiary (ii) entities that are non-VIEs which the Company does not control, but over which the Company has the ability to exercise significant influence and (iii) entities that are non-VIEs that the Company controls through its general partner status, but the limited partners in the entity have the substantive ability to dissolve the entity or remove the Company without cause or have substantive participating rights. The Company continuously assesses its determination of whether an entity is a VIE and who the primary beneficiary is, and whether or not the limited partners in an entity have substantive rights, more particularly if certain events occur that are likely to cause a change in the original determinations. The Company's assessment includes a review of applicable documents such as, but not limited to, applicable partnership agreements, real estate venture agreements, LLC agreements, management and leasing agreements to determine whether the Company has control to direct the business activities of the entities. The portion of the entities that are consolidated but not owned by the Company is presented as non-controlling interest as of and during the periods consolidated. All intercompany accounts and transactions have been eliminated in consolidation.

Use of Estimates

Operating Properties/ Depreciation and Amortization

Purchase Price Allocation

Impairment or Disposal of Long-Lived Assets

Construction in Progress

Cash and Cash Equivalents

Restricted Cash

Accounts Receivable and Accrued Rent Receivable

The allowance is an estimate based on two calculations that are combined to determine the total amount reserved. First, the Company evaluates specific accounts where it has determined that a tenant may have an inability to meet its financial obligations. In these situations, the Company uses its judgment, based on the facts and circumstances, and records a specific reserve for that tenant against amounts due to reduce the receivable to the amount that the Company expects to collect. These reserves are reevaluated and adjusted as additional information becomes available. Second, a reserve is established for all tenants based on a range of percentages applied to receivable aging categories for tenant receivables. For accrued rent receivables, the Company considers the results of the evaluation of specific accounts and also considers other factors including assigning risk factors to different industries based on its tenants SIC classification. Considering various factors including assigning a risk factor to different industries, these percentages are based on historical collection and write-off experience adjusted for current market conditions, which requires management’s judgments.

Investments in Unconsolidated Real Estate Ventures

Deferred Costs

Revenue Recognition

eferred rents on the balance sheet represent rental revenue received prior to their due dates and amounts paid by the tenant for certain improvements considered to be landlord assets that will remain as the Company’s property at the end of the tenant’s lease term. The amortization of the amounts paid by the tenant for such improvements is calculated on a straight-line basis over the term of the tenant’s lease and is a component of straight-line rental income and increased revenue

Lease incentives, which are included as reductions of rental revenue in the accompanying consolidated statements of operations, are recognized on a straight-line basis over the term of the lease.

Income Taxes

The Operating Partnership has elected to treat several of its subsidiaries as taxable TRSs, which are subject to federal, state and local income tax.

Operating Partnership

Parent Company

Earnings Per Unit

Tresaury Shares

Stock-Based Compensation Plans

The expensed amounts are included in general and administrative expense on the Company’s consolidated income statement in the respective periods.

Comprehensive Income

Accounting for Derivative Instruments and Hedging Activities

The ineffective portions of the hedges are recognized in earnings.

Fair Value Measurements


•	Non-financial assets and liabilities initially measured at fair value in an acquisition or business combination that are not remeasured at least annually at fair value,


•	Long-lived assets measured at fair value due to an impairment in accordance with the accounting standard for the impairment or disposal of long-lived assets,


•	Equity and cost method investments measured at fair value due to an impairment in accordance with the accounting standard for investments,


•	Notes receivable adjusted for any impairment in its value in accordance with the accounting standard for loan receivables; and


•	Asset retirement obligations initially measured at fair value under the accounting standard for asset retirement obligations.


•	Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access;

•


•	Level 3 inputs are unobservable inputs for the asset or liability, which is typically based on an entity’s own assumptions, as there is little, if any, related market activity or information.

Accounting Pronouncements Adopted During 2011

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2011

Accounting Policies [Abstract]

Schedule of capitalized salaries including bonuses and benefits



	December 31,
	2011		2010		2009
Development	$	—	$	2,331	$	1,772
Redevelopment	—		127		398
Tenant Improvements	3,539		940		1,757
Total	$	3,539	$	3,398	$	3,927

Schedule of other assets

Other assets is comprised of the following as of December 31, 2011 (in thousands):



	December 31,
	2011		2010
Prepaid Ground Rent	$	7,615	$	7,704
Prepaid Real Estate Taxes	7,983		7,648
Rent inducements, net	7,572		6,262
Cash surrender value of life insurance	9,261		8,128
Restricted cash	2,528		4,029
Marketable securities	2,366		2,614
Prepaid insurance	2,589		2,432
Furniture, fixtures and equipment	634		1,613
Deposits on future settlements	3,884		2,035
Others	8,726		12,232
Total	$	53,158	$	54,697

Fair value of assets and liabilities on recurring basis



	Fair Value Measurements at Reporting Date Using:
Description	December 31, 2011		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Unobservable Inputs (Level 3)
Recurring
Assets:
Available-for-Sale Securities	$	—	$	—	$	—	$	—

Liabilities:
Interest Rate Swaps	$	3,886	$	—	$	3,886	$	—

The following table sets forth the Company’s financial assets and liabilities that were accounted for at fair value on a recurring basis as of December 31, 2010 (in thousands):



	Fair Value Measurements at Reporting Date Using:
Description	December 31, 2010		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Unobservable Inputs (Level 3)
Recurring
Assets:
Available-for-Sale Securities	$	248	$	248	$	—	$	—

- Definition

Tabular disclosure of the fair value measurement of assets and liabilities which includes [financial] instruments measured at fair value that are classified in stockholders' equity. Such assets and liabilities may be measured on a recurring or nonrecurring basis. The disclosures which may be required or desired include: (1) for assets and liabilities measured on a recurring basis, disclosure may include: (a) the fair value measurements at the reporting date; (b) the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets or liabilities (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3); (c) for fair value measurements using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (i) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (ii) purchases, sales, issuances, and settlements (net); (iii) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs); (d) the amount of the total gains or losses for the period in subparagraph (c) (i) above included in earnings (or changes in net assets) that are attributable to the change in unrealized gains or losses relating to those assets and liabilities still held at the reporting date and a description of where those unrealized gains or losses are reported in the statement of income (or activities); (e) the valuation technique(s) used to measure fair value and a discussion of changes in valuation techniques, if any, during the period and (2) for assets and liabilities that are measured at fair value on a nonrecurring basis (for example, impaired assets) disclosure may include, in addition to (a) above: (a) the reasons for the fair value measurements recorded; (b) the same as (b) above; (c) for fair value measurements using significant unobservable inputs (Level 3), a description of the inputs and the information used to develop the inputs; and (d) the valuation technique(s) used to measure fair value and a discussion of changes, if any, in the valuation technique(s) used to measure similar assets and/or liabilities in prior periods. Where the quoted price in an active market for the identical liability is not available, the Level 1 input is the quoted price of an identical liability when traded as an asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 33
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 6
-Footnote 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19190-110258

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19279-110258

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19296-110258

+ Details

Real Estate Investments (Tables)

12 Months Ended

Dec. 31, 2011

Real Estate [Abstract]

Gross carrying value of rental properties



	December 31,
	2011		2010
Land	$	677,891	$	697,724
Building and improvements	3,631,388		3,693,579
Tenant improvements	483,801		442,808
	$	4,793,080	$	4,834,111

Business acquisition, purchase price allocation



	August 5,
	2010
Building and tenant improvements	$	98,188
Intangible assets acquired	28,856
Below market lease liabilities assumed	(683		)
Total	$	126,361

Schedule of Intangibles assets and liabilities acquired



	August 5, 2010		Weighted Average Amortization Period (in years)
Intangible assets:
In-place lease value	$	13,584	3
Tenant relationship value	8,870		5
Above market tenant leases acquired	895		1
Below market ground lease acquired	5,507		82
Total	$	28,856	23
Intangible liabilities:
Below market leases acquired	$	683	1

Operating results of acquired property included in parent company results of operations



	For the period from August 5 to December 31, 2010
Revenue:
Rents	$	6,347
Tenant Reimbursements	933
Other	45
Total revenue	$	7,325
Loss from operations (includes depreciation and intangible asset amortization)	$	(3,602	)

Supplemental pro forma operating data



	December 31,
	2010			2009
	(unaudited)
Pro forma revenues	$	582,642		$	604,440
Pro forma income (loss) from continuing operations	(29,000		)	7,890
Pro forma net income (loss) available to common shareholders	(24,940		)	2,306
Earnings per common share from continuing operations:
Basic — as reported	$	(0.29	)	$	(0.04	)
Basic — as pro forma	$	(0.28	)	$	—
Diluted — as reported	$	(0.29	)	$	(0.04	)
Diluted — as pro forma	$	(0.28	)	$	—
Earnings per common share:
Basic — as reported	$	(0.19	)	$	—
Basic — as pro forma	$	(0.19	)	$	0.02
Diluted — as reported	$	(0.19	)	$	—
Diluted — as pro forma	$	(0.19	)	$	0.02

Investment in Unconsolidated Ventures (Tables)

12 Months Ended

Dec. 31, 2011

Equity Method Investments and Joint Ventures [Abstract]

Schedule of equity method investments



	Ownership Percentage (a)		Carrying Amount			Company’s Share of 2011 Real Estate Venture Income (Loss)			Real Estate Venture Debt at 100%		Current Interest Rate		Debt Maturity
Broadmoor Austin Associates	50	%	$	66,150		$	197		$	66,810	7.04	%	Apr-2023
Brandywine-AI Venture LLC (b)	50	%	24,670			(278		)	68,000		(b)		(b)
Macquarie BDN Christina LLC	20	%	6,168			875			60,000		4.50	%	June-2016
One Commerce Square (c)	25	%	5,100			242			128,529		5.67	%	Dec-15
Brandywine 1919 Ventures (d)	50	%	4,882			—			—		N/A		N/A
Two Commerce Square (c)	25	%	3,415			224			107,112		6.30	%	May-13
1000 Chesterbrook Blvd.	50	%	1,745			245			26,000		4.75	%	Dec-21
Four Tower Bridge (e)	65	%	1,360			702			10,870		5.20	%	Feb-21
G&I Interchange Office LLC (DRA — N. PA) (f)	20	%	1,239			76			181,967		5.78	%	Jan-15
Residence Inn Tower Bridge	50	%	481			433			14,261		5.63	%	Feb-16
PJP VII	25	%	472			190			8,072		L+1.55%		Nov-13
PJP V	25	%	361			116			5,789		6.47	%	Aug-19
PJP II	30	%	300			138			4,263		6.12	%	Nov-23
Six Tower Bridge (e)	63	%	201			126			12,599		7.79	%	Aug-12
Two Tower Bridge	35	%	134			(364		)	13,482		(g)		(g)
Seven Tower Bridge	20	%	105			—			11,182		(h)		(h)
PJP VI	25	%	31			67			8,834		6.08	%	Apr-23
Eight Tower Bridge	3.4	%	—			583			—
Coppell Associates (e)	50	%	(1,007		)	(139		)	18,060		(i)		(i)
Five Tower Bridge			—			60
Invesco, L.P.			—			282
			$	115,807		$	3,775		$	745,830


(a)	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.


(b)	See Note 3 for related discussion about the Brandywine-AI Venture, LLC formation.

(c)


(d)	See Note 3 for related discussion about the Brandywine 1919 Market Ventures formation.


(e)	As a result of the adoption of the new accounting standard for the consolidation of variable interest entities, the Company deconsolidated these three real estate ventures as of January 1, 2010.


(f)	Proceeds received by the Company from the sale of an 80% ownership stake in the properties exceeded the historical cost of those properties. Accordingly, no investment in the real estate venture was reflected on the balance sheet at period end.


(g)	Consists of a $10.1 million fixed rate mortgage with a 5.72% interest rate and May 2013 maturity date; also includes $3.4 million municipal and state borrowings with nominal interest rates (0 — 1%) and maturity dates from 3 to 10 years.

(h)


(i)	Comprised of two fixed rate mortgages: a senior fixed rate note of $16.4 million at 5.75% that matures in March 2016 and a junior fixed rate note of $1.6 million at 6.89% that matures in December 2013; 5.89% is the blended rate.

Financial position of unconsolidated Real Estate Ventures



	December 31,
	2011		2010
Net property	$	846,643	$	804,705
Other assets	110,520		105,576
Other Liabilities	48,798		44,509
Debt	745,830		748,387
Equity	162,535		117,385
Company’s share of equity (Company’s basis)	115,807		84,372

Summary of results of operations of unconsolidated Real Estate Ventures



	Years ended December 31,
	2011 (a)		2010 (a)		2009
Revenue	$	145,867	$	118,923	$	105,236
Operating expenses	63,715		44,942		38,691
Interest expense, net	42,032		37,505		30,858
Depreciation and amortization	39,172		32,703		36,700
Net income	948		3,773		(1,012		)
Company’s share of income (Company’s basis)	3,775		5,305		4,069


(a) -	Includes the three real estate ventures that were deconsolidated upon the adoption of the accounting standard for the consolidation of VIEs on January 1, 2010

Schedule of aggregate principal payments of recourse and non-recourse debt payable to third-parties




2011	$	24,228
2012	143,705
2013	13,809
2014	306,051
2015	97,215
Thereafter	160,822
	$	745,830

Deferred Costs (Tables)

12 Months Ended

Dec. 31, 2011

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Deferred Costs



	December 31, 2011
	Total Cost		Accumulated Amortization			Deferred Costs, net
Leasing Costs	$	140,772	$	(50,990	)	$	89,782
Financing Costs	38,929		(13,349		)	25,580
Total	$	179,701	$	(64,339	)	$	115,362



	December 31, 2010
	Total Cost		Accumulated Amortization			Deferred Costs, net
Leasing Costs	$	123,724	$	(43,930	)	$	79,794
Financing Costs	37,257		(10,934		)	26,323
Total	$	160,981	$	(54,864	)	$	106,117

Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2011

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible assets



	December 31, 2011
	Total Cost		Accumulated Amortization			Intangibles, net
In-place lease value	$	91,426	$	(55,498	)	$	35,928
Tenant relationship value	72,813		(45,114		)	27,699
Above market leases acquired	12,744		(5,856		)	6,888
Total	$	176,983	$	(106,468	)	$	70,515

Below market leases acquired	$	75,685	$	(40,579	)	$	35,106



	December 31, 2010
	Total Cost		Accumulated Amortization			Intangibles, net
In-place lease value	$	108,456	$	(63,010	)	$	45,446
Tenant relationship value	95,385		(52,113		)	43,272
Above market leases acquired	18,319		(9,575		)	8,744
Total	$	222,160	$	(124,698	)	$	97,462

Below market leases acquired	$	67,198	$	(37,965	)	$	29,233

Annual amortization of intangible assets and liabilities



	Assets		Liabilities
2012	$	20,457	$	6,826
2013	12,457		6,312
2014	9,606		4,745
2015	7,207		2,597
2016	4,565		1,704
Thereafter	16,223		12,922
Total	$	70,515	$	35,106

Debt Obligations (Tables)

12 Months Ended

Dec. 31, 2011

Debt Disclosure [Abstract]

Consolidated debt obligations



Property / Location	December 31, 2011			December 31, 2010			Effective Interest Rate			Maturity Date
MORTGAGE DEBT:
Arboretum I, II, III & V	$	—		$	20,386		7.59	%	(a)	Jul-11
Midlantic Drive/Lenox Drive/DCC I	—			56,514			8.05	%	(b)	Oct-11
Research Office Center	—			39,145			5.30	%	(c), (d)	Oct-11
Concord Airport Plaza	—			34,494			5.55	%	(d), (e)	Jan-12
Newtown Square/Berwyn Park/Libertyview	56,538			58,102			7.25	%		May-13
Southpoint III	1,887			2,597			7.75	%		Apr-14
Tysons Corner	94,882			96,507			5.36	%	(d)	Aug-15
Two Logan Square	89,800			89,800			7.57	%		Apr-16
One Logan Square	—			60,000			4.50	%	(f)	Jul-16
Fairview Eleven Tower	22,000			—			4.25	%		Jan-17
IRS Philadelphia Campus	202,905			208,366			7.00	%		Sep-30
Cira South Garage	44,379			46,335			7.12	%		Sep-30
Principal balance outstanding	512,391			712,246
Plus: unamortized fixed-rate debt premiums (discounts), net	(1,330		)	(457		)
Total mortgage indebtedness	$	511,061		$	711,789
UNSECURED DEBT:
$345.0M 3.875% Guaranteed Exchangeable Notes due 2026	—			59,835			5.50	%	(g)	Oct-11
Bank Term Loan	37,500			183,000			LIBOR+0.80%		(h)	Jun-12
Credit Facility	275,500			183,000			LIBOR+0.725%		(h)	Jun-12
$300.0M 5.750% Guaranteed Notes due 2012	151,491			175,200			5.73	%		Apr-12
$250.0M 5.400% Guaranteed Notes due 2014	242,681			242,681			5.53	%		Nov-14
$250.0M 7.500% Guaranteed Notes due 2015	227,329			250,000			7.77	%		May-15
$250.0M 6.000% Guaranteed Notes due 2016	250,000			250,000			5.95	%		Apr-16
$300.0M 5.700% Guaranteed Notes due 2017	300,000			300,000			5.68	%		May-17
$325.0M 4.950% Guaranteed Notes due 2018	325,000			—			5.14	%		Apr-18
Indenture IA (Preferred Trust I)	27,062			27,062			2.75	%		Mar-35
Indenture IB (Preferred Trust I)	25,774			25,774			3.30	%		Apr-35
Indenture II (Preferred Trust II)	25,774			25,774			LIBOR+1.25%			Jul-35
Principal balance outstanding	1,888,111			1,722,326
Less: unamortized exchangeable debt discount	—			(906		)
unamortized fixed-rate debt discounts, net	(5,177		)	(2,763		)
Total unsecured indebtedness	$	1,882,934		$	1,718,657
Total Debt Obligations	$	2,393,995		$	2,430,446


(a)	On April 1, 2011, the Company prepaid the remaining balance of the loan without penalty.


(b)	On June 3, 2011, the Company prepaid the remaining balance of the loan without penalty.


(c)	On June 30, 2011, the Company prepaid the remaining balance of the loan without penalty. The unamortized fixed-rate debt premium of $0.3 million related to this loan was included as part of the gain (loss) on early extinguishment of debt in the Company's consolidated statement of operations during the current year.


(d)	These loans were assumed upon acquisition of the related properties. The interest rates reflect the market rate at the time of acquisition.


(e)	On September 1, 2011, the Company prepaid the remaining balance of the loan without penalty. The unamortized fixed-rate debt premium of $0.2 million related to this loan was included as part of the gain (loss) on early extinguishment of debt in the Company's consolidated statement of operations during the year.


(f)	This mortgage was subject to an interest rate floor of 4.50% on a monthly basis. On July 11, 2011, the Company prepaid the balance of the loan without penalty.

(g)

(h)

Summary of debt repurchases



Notes	Repurchase Amount		Principal		Loss		Deferred Financing Amortization
2011 3.875% Notes	$	59,835	$	59,835	$	—	$	—
2012 5.750% Notes	24,749		23,709		868		32
2015 7.500% Notes	25,140		22,671		2,396		120
	$	109,724	$	106,215	$	3,264	$	152

Schedule of principal payments of debt obligations



2012	$	476,889
2013	66,806
2014	254,787
2015	327,225
2016	347,065
Thereafter	927,730
Total principal payments	2,400,502
Net unamortized premiums/(discounts)	(6,507		)
Outstanding indebtedness	$	2,393,995

Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2011

Fair Value Disclosures [Abstract]

Schedule of financial instruments with fair values different from their carrying amount



	December 31, 2011					December 31, 2010
	Carrying Amount			Fair Value		Carrying Amount			Fair Value
Mortgage payable, net of premiums	$	512,391		$	545,784	$	712,246		$	726,348
Unsecured notes payable, net of discounts	$	1,496,501		$	1,555,633	$	1,277,716		$	1,338,743
Variable Rate Debt Instruments	$	391,610		$	380,786	$	444,610		$	432,556
Notes Receivable	$	31,157	(a)	$	32,756	$	31,216	(a)	$	28,921


(a)	For purposes of this disclosure, one of the notes is presented gross of the deferred gain of $12.9 million arising from the sale of the two Trenton properties in 2009 accounted for under the accounting standard for installment sales.

Risk Management and Use of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2011

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of derivative instruments in statement of financial position, fair value



Hedge Product	Hedge Type	Designation		Notional Amount		Strike		Trade Date	Maturity Date	Fair value
Swap	Interest Rate	Cash Flow	(a)	$	200,000	3.623	%	December 6-13, 2011	February 1, 2019	$	2,820
Swap	Interest Rate	Cash Flow	(a)	127,000		2.702	%	December 9-13, 2011	February 1, 2016	340
Swap	Interest Rate	Cash Flow	(a)	50,000		2.470	%	December 13, 2011	February 1, 2015	65
Swap	Interest Rate	Cash Flow	(a)	23,000		2.513	%	December 7-12, 2011	May 1, 2015	27
Swap	Interest Rate	Cash Flow	(a)	27,062		2.750	%	December 21, 2011	September 30, 2017	244
Swap	Interest Rate	Cash Flow	(a)	25,774		3.300	%	December 22, 2011	January 30, 2021	390
				$	452,836					$	3,886

Discontinued Operations (Tables)

12 Months Ended

Dec. 31, 2011

Discontinued Operations and Disposal Groups [Abstract]

Revenue and expense information for the property classified as discontinued operations



	Years ended December 31,
	2011			2010		2009
Revenue:
Rents	$	3,779		$	9,363	$	19,095
Tenant reimbursements	1,198			3,678		8,453
Termination fees	33			190		—
Other	(50		)	70		238
Total revenue	4,960			13,301		27,786
Expenses:
Property operating expenses	1,717			4,641		9,884
Real estate taxes	559			1,816		3,769
Depreciation and amortization	1,431			4,185		7,173
Total operating expenses	3,707			10,642		20,826
Income from discontinued operations before gain on sale of interests in real estate	1,253			2,659		6,960
Net gain on disposition of discontinued operations	7,264			11,011		1,241
Provision for impairment	—			—		(3,700		)
Income from discontinued operations	$	8,517		$	13,670	$	4,501

Beneficiaries Equity of The Parent Company (Tables)

12 Months Ended

Dec. 31, 2011

Equity [Abstract]

Earnings per Share (EPS)



	Years ended December 31,
	2011						2010						2009
	Basic			Diluted			Basic			Diluted			Basic			Diluted
Numerator
Income (loss) from continuing operations	$	(13,232	)	$	(13,232	)	$	(31,276	)	$	(31,276	)	$	3,588		$	3,588
Net (loss) income from continuing operations attributable to non-controlling interests	548			548			820			820			58			58
Amount allocable to unvested restricted shareholders	(505		)	(505		)	(512		)	(512		)	(279		)	(279		)
Preferred share dividends	(7,992		)	(7,992		)	(7,992		)	(7,992		)	(7,992		)	(7,992		)
Loss from continuing operations available to common shareholders	(21,181		)	(21,181		)	(38,960		)	(38,960		)	(4,625		)	(4,625		)
Income from discontinued operations	8,517			8,517			13,670			13,670			4,501			4,501
Discontinued operations attributable to non-controlling interests	(332		)	(332		)	(288		)	(288		)	(121		)	(121		)
Discontinued operations attributable to common shareholders	8,185			8,185			13,382			13,382			4,380			4,380
Net loss available to common shareholders	$	(12,996	)	$	(12,996	)	$	(25,578	)	$	(25,578	)	$	(245	)	$	(245	)
Denominator
Weighted-average shares outstanding	135,444,424			135,444,424			131,743,275			131,743,275			111,898,045			111,898,045
Contingent securities/Stock based compensation	—			—			—			—			—			1,353,246
Total weighted-average shares outstanding	135,444,424			135,444,424			131,743,275			131,743,275			111,898,045			113,251,291
Earnings (loss) per Common Share:
Loss from continuing operations attributable to common shareholders	$	(0.16	)	$	(0.16	)	$	(0.29	)	$	(0.29	)	$	(0.04	)	$	(0.04	)
Discontinued operations attributable to common shareholders	0.06			0.06			0.10			0.10			0.04			0.04
Net loss attributable to common shareholders	$	(0.10	)	$	(0.10	)	$	(0.19	)	$	(0.19	)	$	—		$	—

Partners Equity of The Operating Partnership (Tables)

12 Months Ended

Dec. 31, 2011

Equity [Abstract]

Earnings per Common Partnership Unit



	Years ended December 31,
	2011						2010						2009
	Basic			Diluted			Basic			Diluted			Basic			Diluted
Numerator
Income (loss) from continuing operations	$	(13,232	)	$	(13,232	)	$	(31,276	)	$	(31,276	)	$	3,588		$	3,588
Net (loss) income from continuing operations attributable to non-controlling interests	—			—			—			—			(30		)	(30		)
Amount allocable to unvested restricted unitholders	(505		)	(505		)	(512		)	(512		)	(279		)	(279		)
Preferred share dividends	(7,992		)	(7,992		)	(7,992		)	(7,992		)	(7,992		)	(7,992		)
Loss from continuing operations available to common unitholders	(21,729		)	(21,729		)	(39,780		)	(39,780		)	(4,713		)	(4,713		)
Discontinued operations attributable to common unitholders	8,517			8,517			13,670			13,670			4,501			4,501
Net loss available to common unitholders	$	(13,212	)	$	(13,212	)	$	(26,110	)	$	(26,110	)	$	(212	)	$	(212	)
Denominator
Weighted-average units outstanding	145,118,841			145,118,841			137,454,796			137,454,796			114,712,869			114,712,869
Contingent securities/Stock based compensation	—			—			—			—			—			1,353,246
Total weighted-average units outstanding	145,118,841			145,118,841			137,454,796			137,454,796			114,712,869			116,066,115
Earnings (loss) per Common Share:
Loss from continuing operations attributable to common unitholders	$	(0.15	)	$	(0.15	)	$	(0.29	)	$	(0.29	)	$	(0.04	)	$	(0.04	)
Discontinued operations attributable to common unitholders	0.06			0.06			0.10			0.10			0.04			0.04
Net loss attributable to common unitholders	$	(0.09	)	$	(0.09	)	$	(0.19	)	$	(0.19	)	$	—		$	—

Share Based Compensation, 401(k) Plan and Deferred Compensation (Tables)

12 Months Ended

Dec. 31, 2011

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Option activity



	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value
Outstanding at January 1, 2011	3,116,611		$	14.56	7.81	$	(9,080,625	)
Granted	603,241		11.89		9.18	(1,441,746		)
Exercised	(120,180	)	2.91
Outstanding at December 31, 2011	3,599,672		$	14.50	7.20	$	(18,015,060	)
Vested/Exercisable at December 31, 2011	2,287,729		$	17.01	6.59	$	(16,912,225	)



	Years ended December 31,
	2010					2009
	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in Years)	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in Years)
Outstanding at beginning of year	2,404,567		$	15.48	8.38	1,754,648		$	20.41	8.77
Granted	724,805		11.31		9.18	676,491		2.91		9.25
Forfeited/Expired	(12,761	)	2.91		—	(26,572	)	20.61		—
Outstanding at end of year	3,116,611		$	14.56	7.81	2,404,567		$	15.48	8.38
Vested/Exercisable at end of year	1,384,728		$	17.63	7.14	616,119		$	20.03	7.54

Schedule of share-based payment award, stock options, valuation assumptions



Grant Date	March 2, 2011		March 4, 2010
Risk-free interest rate	2.86%		3.03%
Dividend yield	5.01%		6.53%
Volatility factor	48.02%		46.89%
Weighted-average expected life	7	yrs	7	yrs

Company's restricted share activity



	Shares		Weighted Average Grant Date Fair value
Non-vested at January 1, 2011	851,278		$	10.75
Granted	197,035		11.92
Vested	(237,541	)	19.76
Forfeited	(3,481	)	11.47
Non-vested at December 31, 2011	807,291		$	9.46

Distributions (Tables)

12 Months Ended

Dec. 31, 2011

Distributions [Abstract]

Schedule of Dividends Payable

DISTRIBUTIONS



	Years ended December 31,
	2011			2010			2009
Common Share Distributions:
Ordinary income	$	0.37		$	0.60		$	0.60
Capital gain	—			—			—
Non-taxable distributions	0.23			—			—
Distributions per share	$	0.60		$	0.60		$	0.60
Percentage classified as ordinary income	61.67		%	100		%	100		%
Percentage classified as capital gain	—		%	—		%	—		%
Percentage classified as non-taxable distribution	38.33		%	—		%	—		%
Preferred Share Distributions:
Total distributions declared	$	7,992,000		$	7,992,000		$	7,992,000

Accumulated Other Comprehensive Income (Loss) (Tables)

12 Months Ended

Dec. 31, 2011

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Schedule of accumulated other comprehensive income (loss)



Parent Company	Unrealized Gains (Losses) on Securities			Cash Flow Hedges			Accumulated Other Comprehensive Loss
Balance at January 1, 2009	$	(9	)	$	(16,996	)	$	(17,005	)
Change during year	—			7,395			7,395
Non-controlling interest — consolidated real estate venture partner’s share of unrealized (gains)/losses on derivative financial instruments	—			290			290
Ineffectiveness of forward starting swaps	—			(125		)	(125		)
Other	—			491			491
Reclassification adjustments for (gains) losses reclassified into operations	—			(184		)	(184		)
Balance at December 31, 2009	$	(9	)	$	(9,129	)	$	(9,138	)
Change during year	—			7,320			7,320
Non-controlling interest — consolidated real estate venture partner’s share of unrealized (gains)/losses on derivative financial instruments	—			(155		)	(155		)
Reclassification adjustments for (gains) losses reclassified into operations	—			28			28
Balance at December 31, 2010	$	(9	)	$	(1,936	)	$	(1,945	)
Change during year	—			(4,499		)	(4,499		)
Non-controlling interest — consolidated real estate venture partner’s share of unrealized (gains)/losses on derivative financial instruments	—			212			212
Reclassification adjustments for (gains) losses reclassified into operations	—			153			153
Balance at December 31, 2011	$	(9	)	$	(6,070	)	$	(6,079	)



Operating Partnership	Unrealized Gains (Losses) on Securities			Cash Flow Hedges			Accumulated Other Comprehensive Loss
Balance at January 1, 2009	$	(9	)	$	(16,996	)	$	(17,005	)
Change during year	—			7,395			7,395
Ineffectiveness of forward starting swaps	—			(125		)	(125		)
Other	—			491			491
Reclassification adjustments for (gains) losses reclassified into operations	—			(184		)	(184		)
Balance at December 31, 2009	$	(9	)	$	(9,419	)	$	(9,428	)
Change during year	—			7,320			7,320
Reclassification adjustments for (gains) losses reclassified into operations	—			28			28
Balance at December 31, 2010	$	(9	)	$	(2,071	)	$	(2,080	)
Change during year				(4,499		)	(4,499		)
Reclassification adjustments for (gains) losses reclassified into operations	—			153			153
Balance at December 31, 2011	$	(9	)	$	(6,417	)	$	(6,426	)

Segment Information (Tables)

12 Months Ended

Dec. 31, 2011

Segment Reporting [Abstract]

Segment information



	Pennsylvania Suburbs		Philadelphia CBD		Metropolitan, D.C.		New Jersey /Delaware		Richmond, Virginia		Austin, Texas		California		Corporate			Total
2011:
Real estate investments, at cost:
Operating properties	$	1,218,071	$	953,870	$	1,255,803	$	545,657	$	307,698	$	257,694	$	254,287	$	—		$	4,793,080
Construction-in-progress															25,083			$	25,083
Land inventory															109,008			$	109,008
Total revenue	158,248		125,366		128,456		81,629		36,789		30,895		21,670		(1,248		)	581,805
Property operating expenses, real estate taxes and third party management expenses	58,440		48,792		47,786		40,500		14,727		13,048		11,507		(989		)	233,811
Net operating income	$	99,808	$	76,574	$	80,670	$	41,129	$	22,062	$	17,847	$	10,163	$	(259	)	$	347,994
2010:
Real estate investments, at cost:
Operating properties	$	1,199,957	$	911,354	$	1,359,776	$	568,413	$	294,406	$	254,019	$	246,186	$	—		$	4,834,111
Construction-in-progress	—		—		—		—		—		—		—		33,322			33,322
Land inventory	—		—		—		—		—		—		—		110,055			110,055
Total revenue	152,380		92,110		137,923		87,711		36,032		32,049		22,551		(800		)	559,956
Property operating expenses, real estate taxes and third party management expenses	59,065		37,896		48,318		44,137		14,010		13,401		11,852		(1,338		)	227,341
Net operating income	$	93,315	$	54,214	$	89,605	$	43,574	$	22,022	$	18,648	$	10,699	$	538		$	332,615
2009:
Real estate investments, at cost:
Operating properties	$	1,219,391	$	490,602	$	1,372,213	$	605,181	$	301,474	$	268,806	$	254,951	$	—		$	4,512,618
Construction-in-progress	—				—		—		—		—		—		271,962			271,962
Land inventory	—				—		—		—		—		—		97,368			97,368
Total revenue	157,616		73,534		140,438		98,344		36,201		31,311		29,283		1,193			567,920
Property operating expenses, real estate taxes and third party management expenses	56,297		31,479		52,899		45,421		13,871		14,351		14,735		(1,893		)	227,160
Net operating income	$	101,319	$	42,055	$	87,539	$	52,923	$	22,330	$	16,960	$	14,548	$	3,086		$	340,760

Reconciliation of consolidated net operating income



	Year Ended December 31,
	2011			2010			2009
	(amounts in thousands)
Consolidated net operating income	$	347,994		$	332,615		$	340,760
Less:
Interest expense	(131,405		)	(132,640		)	(135,740		)
Deferred financing costs	(4,991		)	(3,770		)	(5,864		)
Depreciation and amortization	(217,680		)	(210,592		)	(203,572		)
Administrative expenses	(24,602		)	(23,306		)	(20,821		)
Recognized Hedge Activity	—			—			(916		)
Plus:
Interest income	1,813			3,222			2,499
Historic tax credit transaction income	12,026			—			—
Equity in income of real estate ventures	3,775			5,305			4,069
Net gain on sales of interests in real estate ventures	2,791			—			(3		)
Net gain on sale of undepreciated real estate	45			—			—
Loss on real estate venture formation	(222		)	—			—
Gain (loss) on early extinguishment of debt	(2,776		)	(2,110		)	23,176
Income (loss) from continuing operations	(13,232		)	(31,276		)	3,588
Income from discontinued operations	8,517			13,670			4,501
Net income (loss)	$	(4,715	)	$	(17,606	)	$	8,089

- Definition

Tabular disclosure of the profit or loss and total assets for each reportable segment. An entity discloses certain information on each reportable segment if the amounts (a) are included in the measure of segment profit or loss reviewed by the chief operating decision maker or (b) are otherwise regularly provided to the chief operating decision maker, even if not included in that measure of segment profit or loss.

+ References + Details

Operating Leases (Tables)

12 Months Ended

Dec. 31, 2011

Leases, Operating [Abstract]

Operating Leases Future Minimum Payments Due



Year	Minimum Rent
2012	$	443,103
2013	424,764
2014	384,539
2015	344,641
2016	295,045
Thereafter	1,090,697



2012	$	1,818
2013	1,818
2014	1,818
2015	1,909
2016	1,909
Thereafter	289,440

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2011

Commitments and Contingencies Disclosure [Abstract]

Operating Leases Future Minimum Payments Due



Year	Minimum Rent
2012	$	443,103
2013	424,764
2014	384,539
2015	344,641
2016	295,045
Thereafter	1,090,697



2012	$	1,818
2013	1,818
2014	1,818
2015	1,909
2016	1,909
Thereafter	289,440

Summary of Quarterly Results (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2011

Quarterly Financial Information Disclosure [Abstract]

Schedule of quarterly financial information



	1st Quarter (a)			2nd Quarter (b)			3rd Quarter			4th Quarter
2011:
Total revenue	$	146,794		$	144,094		$	144,308		$	146,609
Net income (loss)	(490		)	(6,234		)	6,611			(4,602		)
Net income (loss) allocated to Common Shares	(439		)	(6,069		)	6,249			(4,240		)
Basic earnings (loss) per Common Share	$	(0.02	)	$	(0.06	)	$	0.03		$	(0.05	)
Diluted earnings (loss) per Common Share	$	(0.02	)	$	(0.06	)	$	0.03		$	(0.05	)
2010:
Total revenue	$	139,502		$	134,191		$	140,179		$	146,084
Net loss	(399		)	(5,600		)	(6,616		)	(4,991		)
Loss allocated to Common Shares	(348		)	(5,441		)	(6,437		)	(4,848		)
Basic loss per Common Share	$	(0.02	)	$	(0.06	)	$	(0.06	)	$	(0.05	)
Diluted loss per Common Share	$	(0.02	)	$	(0.06	)	$	(0.06	)	$	(0.05	)

(a)

(b)

Organization of The Parent Company and The Operating Partnership (Details) sqft in Millions	12 Months Ended
	Dec. 31, 2011 sqft Properties Real_Estate_Investments A managementcompanies	Mar. 31, 2011
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Ownership in the Operating Partnership	98.10%
Number of properties with ownership interest		3
Number of Third-party real estate management services businesses that conduct business with Company \| managementcompanies	6
Area of undeveloped parcels of land (in acres) owned by a Real Estate Venture \| A	4
Parent Company [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Net rentable square feet	25.2
Area of undeveloped parcels of land (in acres) owned by a Real Estate Venture \| A	444
Area of additional undeveloped parcels of land with option to purchase \| A	52
Unconsolidated real estate ventures [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Number of unconsolidated real estate ventures \| Real_Estate_Investments	18
Net rentable square feet	6.7
Wholly-owned management company subsidiaries [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Net rentable square feet	32.6
Ownership in Management Companies, directly and indirectly	100.00%
Third Parties and Unconsolidated Real Estate Ventures [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Net rentable square feet	7.4
Office Properties [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Number of properties with ownership interest \| Properties	207
Industrial facilities [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Number of properties with ownership interest \| Properties	20
Mixed-use properties [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Number of properties with ownership interest \| Properties	5

Summary of Significant Accounting Policies (Principles of Consolidation/ Depreciation and Amortization) (Details Textuals) $ in Millions	12 Months Ended
	Dec. 31, 2011 USD ($) Years	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Dec. 31, 2008 USD ($)	Dec. 31, 2007 USD ($)	Dec. 31, 2006 USD ($)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Buildings and improvements, useful life, minimum \| Years	5
Buildings and improvements, useful life, maximum \| Years	55
PJP VII [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Payment guarantees other than the guarantee	$ 0.7
Restatement Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Depreciation and amortization expense relating to intangibles	$ 4.7	$ 1.7	$ (1.4)	$ (1.8)	$ (1.7)	$ (1.5)
Depreciation expense related to projects completed in prior years		$ (1.2)	$ 0.9	$ 0.2

Summary of Significant Accounting Policies (Construction in Progress) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Construction in Progress [Line Items]
Internal direct construction costs capitalized related to development of properties and land holdings	$ 3,500	$ 3,400	$ 3,900
Interest costs, capitalized during period	2,000	10,400	8,900
Salaries (including bonuses and benefits) capitalized during the period	3,539	3,398	3,927
Development [Member]
Construction in Progress [Line Items]
Salaries (including bonuses and benefits) capitalized during the period	0	2,331	1,772
Redevelopment [Member]
Construction in Progress [Line Items]
Salaries (including bonuses and benefits) capitalized during the period	0	127	398
Tenant Improvements [Member]
Construction in Progress [Line Items]
Salaries (including bonuses and benefits) capitalized during the period	$ 3,539	$ 940	$ 1,757

Summary of Significant Accounting Policies (Accounts Receivable and Accrued Rent Receivable/Deferred Costs/ Treasury Shares) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2011 USD ($) Years shares	Dec. 31, 2010 USD ($) shares
Accounting Policies [Abstract]
Tenant receivables and accrued rent receivables, gross \| $	$ 3.4	$ 3.7
Allowance for doubtful accounts receivable \| $	$ 12.1	$ 11.6
Deferred leasing costs, amortization period, minimum \| Years	1
Deferred leasing costs, amortization period, ,maximum \| Years	15
Treasury stock, shares \| shares	0	116,679

Summary of Significant Accounting Policies (Other Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2011	Dec. 31, 2010
Other Assets
Prepaid Ground Rent	$ 7,615	$ 7,704
Prepaid Real Estate Taxes	7,983	7,648
Rent inducements, net	7,572	6,262
Cash surrender value of life insurance	9,261	8,128
Restricted cash	2,528	4,029
Marketable securities	2,366	2,614
Prepaid insurance	2,589	2,432
Furniture, fixtures and equipment	634	1,613
Deposits on future settlements	3,884	2,035
Others	8,726	12,232
Total	$ 53,158	$ 54,697

Summary of Significant Accounting Policies (Notes Receivable) (Details) $ in Thousands		12 Months Ended
	Dec. 29, 2010 USD ($) Note_Receivable_Forclosed	Dec. 31, 2011 USD ($) Properties	Dec. 31, 2010 USD ($) Properties	Dec. 31, 2009 USD ($) Properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable		$ 18,186	$ 18,205
Number of properties sold \| Properties		19	19	19
Purchase money mortgage loan repayments terms		start in 2012, to be fully paid in 2014
Number of foreclosed note receivables \| Note_Receivable_Forclosed	1
Settlement of note receivable through foreclosure of a parcel of land		$ 0	$ 2,795	$ 0
20 Year Amortization Period [Member] \| Purchase money mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable		$ 7,200	$ 7,400
Interest rate		8.50%	8.50%
Notes receivable amortization period, years		20 years	20 years
Due 2015 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable		$ 500	$ 800
Interest rate		10.00%	10.00%
Due 2016 [Member] \| Purchase money mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable		$ 23,400	$ 22,900
Notes receivable amortization period, years		7 years	7 years
Cash pay interest rate		6.00%	6.00%
Interest accrual rate		7.64%	7.64%
Trenton Properties [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable		$ 23,400
Number of properties sold \| Properties		2
Gross deferred gain on sale of properties		$ 12,900
Expected proceeds from collection of notes receivable		$ 27,800
Gibbsboro, New Jersey [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Settlement of note receivable through foreclosure of a parcel of land	$ 2,800

Summary of Significant Accounting Policies (Impairment or Disposal of Long-Lived Assets/ Revenue Recognition/ Stock-Based Compensation Plans) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2011 USD ($) Properties shares	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Dec. 31, 2008 USD ($)	Jun. 02, 2010 shares
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Development expense for land	$ 7.7
Revenue increased by straight-line rent adjustment	17.9	$ 10.9	$ 6.4
Increased revenue due to amortization of deferred rent	2.4	2.8	2.7
Decrease in revenue due to amortization of lease incentives	1.6	1.5	1.8
Additional income related to electricity charges	0.5
Overstatement of revenue due to under billing	$ (0.5)
Understatement of Revenue			0.3	$ 0.2
Increase in Common shares available for future awards \| shares					6,000,000
Increase in shares due to amendments in plan, shares solely available for options and share appreciation rights \| shares	3,971,774				3,600,000
Common shares available for future awards \| shares	5,789,202
Options awarded, term	one to ten-year
Award vesting term, minimum	1 year
Award vesting term, maximum	10 years
Stock-based compensation expense	$ 6.4	6.1	5.3
Stock-based compensation expense, capitalized	$ 1.5	$ 1.3	$ 0.8
Requirement to commence development by 2012 [Member]
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Number of parcels of land under option for ground lease \| Properties	2

Summary of Significant Accounting Policies (Income Taxes) (Details) - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Income Tax Contingency [Line Items]
Distributable income minimum percentage	90.00%
Tax basis of assets	$ 4.5	$ 4.5
Amount of Federal excise tax if sufficient taxable income is not distributed within prescribed time limits	4.00%
Excise tax annual amount, if certain requirements are not meant	4.00%
Excise tax, if sum of ordinary income is less than	85.00%
Excise tax, if Net capital gain exceeds cash distributions and certain taxes paid	95.00%
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Income Tax Contingency [Line Items]
Tax basis of assets	$ 4.5	$ 4.5
Amount of Federal excise tax if sufficient taxable income is not distributed within prescribed time limits	4.00%
Excise tax annual amount, if certain requirements are not meant	4.00%
Excise tax, if sum of ordinary income is less than	85.00%
Excise tax, if Net capital gain exceeds cash distributions and certain taxes paid	95.00%

Summary of Significant Accounting Policies (Fair Value Measurements/ Accounting for Derivative Instruments and Hedge Activities) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2009 USD ($) Interest_rate_swaps	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)
Assets:
Available-for-Sale Securities		$ 0	$ 248
Liabilities:
Interest Rate Swaps		3,886
Derivative Instrument and Hedging Activites
Gain on fair value hedge ineffectiveness	$ 100
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets:
Available-for-Sale Securities		0	248
Liabilities:
Interest Rate Swaps		0
Significant Other Observable Inputs (Level 2) [Member]
Assets:
Available-for-Sale Securities		0	0
Liabilities:
Interest Rate Swaps		3,886
Unobservable Inputs (Level 3) [Member]
Assets:
Available-for-Sale Securities		0	$ 0
Liabilities:
Interest Rate Swaps		$ 0
Interest Rate Swap [Member]
Derivative Instrument and Hedging Activites
Number of interest rate derivatives held \| Interest_rate_swaps	2
Fair value adjustment of the hedge charged to expenses	$ (1,100)

Real Estate Investments (Gross Carrying Value of Company's Properties) (Details) - USD ($) $ in Thousands	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Gross carrying value of rental properties
Land	$ 677,891	$ 697,724
Building and improvements	3,631,388	3,693,579
Tenant improvements	483,801	442,808
Rental properties	$ 4,793,080	$ 4,834,111	$ 4,512,618

Real Estate Investments (Brandy-Al Venture) (Details)
$ in Thousands

12 Months Ended

Dec. 20, 2011

USD ($)

Years

Properties

Dec. 31, 2011

USD ($)

sqft

Properties

Dec. 31, 2010

USD ($)

Dec. 31, 2009

USD ($)

Aug. 12, 2011

sqft

Mar. 31, 2011

Nov. 30, 2010

Joint venture

Company's ownership percentage in the Real Estate Venture

25.00%

Total mortgage indebtedness

$ 511,061

$ 711,789

Number of office buildings in Real Estate Venture

Net rentable space | sqft

192,707

Payments from Joint Venture to acquire properties

$ 40,674

50,681

$ 0

Sourcing additional acquisitions over investment period

3 years

Net loss on partial sale of properties

$ (2,791)

$ 3

Company's share of equity (Company's basis)

115,807

84,372

Balance of the financing obligation

$ 45,528

$ 36,515

Brandywine - Al Venture [Member]

Joint venture

Company's ownership percentage in the Real Estate Venture

50.00%

^[1],[2]

Total mortgage indebtedness

$ 22,000

Number of office buildings in Real Estate Venture | Properties

Net rentable space | sqft

587,317

Amount contributed (net of closing costs and customary propations) to the capital of the Venture

$ 32,200

Debt intstrument weighted average debt securities, years | Years

7.4

Payments from Joint Venture to acquire properties

$ 156,000

Sales of properties, net

120,100

Transaction and joint Venture costs

$ 2,900

Net loss on partial sale of properties

$ 100

Basis adjustment in equity method investment

100

Company's share of equity (Company's basis)

^[2]

24,670

Proceeds from financing obligation

7,500

Balance of the financing obligation

$ 7,500

Brandywine - Al Venture [Member] | Current Creek [Member]

Joint venture

Company's ownership percentage in the Real Estate Venture

50.00%

Brandywine - Al Venture [Member] | Mortgages [Member]

Joint venture

Debt instrument, face amount

$ 90,000

Weighted average interest rate of debt

4.40%

[1]	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.
[2]	See Note 3 for related discussion about the Brandywine-AI Venture, LLC formation.

Real Estate Investments (Acquistions) (Details)		12 Months Ended
Real Estate Investments (Acquistions) (Details)	Dec. 29, 2010 USD ($) A	Dec. 31, 2011 USD ($) sqft	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Aug. 12, 2011 USD ($) sqft	Mar. 28, 2011 USD ($) sqft	Jan. 20, 2011 USD ($) A	Aug. 05, 2010 USD ($) Storey Units_of_limited_partnership_interest $ / shares
Real Estate Investments (Textuals) [Abstract]
Acquired real estate, cost of property					$ 18,800,000
Date which note receivable obtained from third party in connection with acquisition					Aug. 02, 2011
Net rentable space of property acquired \| sqft					192,707
Lease percentage of acquired property		57.20%
Acquisition related costs					$ 300,000
Business acquisition, purchase price allocated to building					21,400,000
Business acquisition, purchase price allocated to intangible assets					12,000,000
Business acquisition, purchase price allocated to market lease liabilities					14,400,000
Business acquisition, purchase price allocated to other assets					200,000
Business acquisition, purchase price allocated to assumed liabilities					$ 400,000
Assumed security deposits obligations		$ 700,000
Settlement of note receivable through foreclosure of a parcel of land		0	$ 2,795,000	$ 0
Land available for development		$ 109,008,000	$ 110,055,000	$ 97,368,000
Overlook I And II [Member]
Real Estate Investments (Textuals) [Abstract]
Acquired real estate, cost of property						$ 12,600,000
Net rentable space of property acquired \| sqft						126,496
Lease percentage of acquired property		100.00%
Parcel of land in PA [Member]
Real Estate Investments (Textuals) [Abstract]
Acquired real estate, cost of property							$ 9,300,000
Acquisition related costs							$ 500,000
Area of land acquired \| A							1
Business Acquisition, consideration received							$ 4,900,000
Parcel of land in PA [Member] \| Partnership Interest [Member]
Real Estate Investments (Textuals) [Abstract]
Business Acquisition, Equity Interest Issued or Issuable, Description							50% general partner interest in the venture
Three Logan Square [Member]
Real Estate Investments (Textuals) [Abstract]
Acquired real estate, cost of property								$ 129,000,000
Net rentable space of property acquired \| sqft		1,000,000
Lease percentage of acquired property		67.20%
Acquisitions through cash								51,200,000
Acquisition related costs								$ 400,000
Number of storey of office tower acquired \| Storey								53
Assumed security deposits obligations								$ 900,000
Net amount of cash paid after assumed liabilities								50,300,000
Closing market price of Parent Company's common shares on acquisition date								$ 11.54
Annual dividend rate per share \| $ / shares								$ 0.60
Recognized tenant and other receivables from acquisition								$ 1,100,000
Prepaid real estate taxes from acquisition								$ 1,500,000
Three Logan Square [Member] \| Partnership Interest [Member]
Real Estate Investments (Textuals) [Abstract]
Business Acquisition, Equity Interest Issued or Issuable, Number of Units \| Units_of_limited_partnership_interest								7,111,112
Gibbsboro, New Jersey [Member]
Real Estate Investments (Textuals) [Abstract]
Area of land acquired \| A	12
Settlement of note receivable through foreclosure of a parcel of land	$ 2,800,000
Land available for development	$ 300,000

Real Estate Investments (Dispositions) (Details) $ in Millions			3 Months Ended
	Oct. 28, 2011 USD ($) Properties sqft	Dec. 23, 2010 USD ($) Properties sqft	Mar. 31, 2011 USD ($)	Dec. 31, 2011 A	Nov. 22, 2011 USD ($) sqft	Oct. 14, 2011 USD ($) A	Jun. 27, 2011 USD ($) sqft	Nov. 22, 2010 USD ($) sqft	Sep. 20, 2010 USD ($) sqft	Aug. 18, 2010 USD ($) sqft	Jan. 14, 2010 USD ($) sqft
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of undeveloped parcels of land \| A				4
Gain on sale of ownership interest			$ 2.8
Number of properties with ownership interest			3
Remaining ownership interest in real estate properties			11.00%
Four Four Two Creamery Way [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net rentable square feet of properties sold \| sqft					104,500
Sales price of properties sold					$ 7.4
Lease percentage of sold property					100.00%
Five Greentree Center and Lake Center II [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of office properties sold (in properties) \| Properties	2
Net rentable square feet of properties sold \| sqft	206,243
Sales price of properties sold	$ 22.8
Five Greentree Centre [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Lease percentage of sold property	92.20%
Lake Center II [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Lease percentage of sold property	47.80%
Three Greentree Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net rentable square feet of properties sold \| sqft							69,300
Sales price of properties sold							$ 5.9
Lease percentage of sold property							13.90%
One and Two Greentree Centre, 8000 Lincoln Drive, and Lake Center IV [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of office properties sold (in properties) \| Properties		4
Net rentable square feet of properties sold \| sqft		243,195
Sales price of properties sold		$ 20.9
Lease percentage of sold property		76.10%
Spyglass Point [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net rentable square feet of properties sold \| sqft								58,576
Sales price of properties sold								$ 13.5
630 Clark Avenue [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net rentable square feet of properties sold \| sqft									50,000
Sales price of properties sold									$ 3.6
479 Thomas Jones Way [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net rentable square feet of properties sold \| sqft										49,264
Sales price of properties sold										$ 3.8
Lease percentage of sold property										63.00%
Westmoreland Plaza [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net rentable square feet of properties sold \| sqft											121,815
Sales price of properties sold											$ 10.8
Dallas, Texas [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales price of properties sold						$ 0.6
Area of undeveloped parcels of land \| A						6

Real Estate Investments (Purchase Price of Allocation) (Details) - Three Logan Square [Member] $ in Thousands	Aug. 05, 2010 USD ($)
Purchase price of allocation
Building and tenant improvements	$ 98,188
Intangible assets acquired	28,856
Below market lease liabilities assumed	(683)
Total	$ 126,361

Real Estate Investments (Summary of Intangible Assets Acquired and Intangible Liabilities Assumed) (Details) - Three Logan Square [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2011 Years	Aug. 05, 2010 USD ($)
Intangible assets:
Intangible assets acquired		$ 28,856
Weighted Average Amortization Period (in years) \| Years	23
Intangible liabilities:
Below market leases assumed		683
Leases, Acquired-in-Place [Member]
Intangible assets:
Intangible assets acquired		13,584
Weighted Average Amortization Period (in years) \| Years	3
Customer Relationships [Member]
Intangible assets:
Intangible assets acquired		8,870
Weighted Average Amortization Period (in years) \| Years	5
Above market tenant leases acquired [Member]
Intangible assets:
Intangible assets acquired		895
Weighted Average Amortization Period (in years) \| Years	1
Below market ground lease acquired [Member]
Intangible assets:
Intangible assets acquired		5,507
Weighted Average Amortization Period (in years) \| Years	82
Intangible liabilities:
Below market leases assumed		$ 683
Weighted Average Amortization Period (in years) \| Years	1

Real Estate Investments (Results of Operations from Acquisition Date) (Details) - USD ($)
$ in Thousands

3 Months Ended

5 Months Ended

12 Months Ended

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

^[1]

Mar. 31, 2011

^[2]

Dec. 31, 2010

Sep. 30, 2010

Jun. 30, 2010

^[1]

Mar. 31, 2010

^[2]

Dec. 31, 2010

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Revenue:

Rents

$ 480,600

$ 461,101

$ 467,188

Tenant Reimbursements

81,236

77,139

76,652

Other

5,440

4,310

3,328

Total revenue

$ 146,609

$ 144,308

$ 144,094

$ 146,794

$ 146,084

$ 140,179

$ 134,191

$ 139,502

$ 581,805

$ 559,956

$ 567,920

Three Logan Square [Member]

Revenue:

Rents

$ 6,347

Tenant Reimbursements

933

Other

Total revenue

7,325

Loss from operations (includes depreciation and intangible asset amortization)

$ (3,602)

[1]

[2]

Real Estate Investments (Pro Forma Operations Data) (Details) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

^[1]

Mar. 31, 2011

^[2]

Dec. 31, 2010

Sep. 30, 2010

Jun. 30, 2010

^[1]

Mar. 31, 2010

^[2]

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Supplemental Pro Forma Operating Data [Abstract]

Pro forma revenues

$ 582,642

$ 604,440

Pro forma income (loss) from continuing operations

(29,000)

7,890

Pro forma net income (loss) available to common shareholders

$ (24,940)

$ 2,306

Loss per common share from continuing operations :

Basic - as reported

$ (0.16)

$ (0.29)

$ (0.04)

Basic -- as pro forma

(0.28)

0.00

Diluted - as reported

(0.16)

(0.29)

(0.04)

Diluted - as pro forma

(0.28)

0.00

Earnings per Common Share

Net income (loss) attributable to common shareholders, Basic

$ (0.05)

$ 0.03

$ (0.06)

$ (0.02)

$ (0.05)

$ (0.06)

$ (0.02)

(0.10)

(0.19)

0.00

Basic -- as pro forma

(0.19)

0.02

Net income (loss) attributable to common shareholders, Diluted

$ (0.05)

$ 0.03

$ (0.06)

$ (0.02)

$ (0.05)

$ (0.06)

$ (0.02)

$ (0.10)

(0.19)

0.00

Diluted - as pro forma

$ (0.19)

$ 0.02

[1]

[2]

Investment in Unconsolidated Ventures (Narrative) (Details)
$ in Thousands, sqft in Millions

12 Months Ended

Dec. 31, 2011

USD ($)

sqft

Buildings

Fixed_Rate_Mortgages

Real_Estate_Investments

Real_Estate_Ventures

Room

Nov. 30, 2010

Buildings

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Number of unconsolidated Real Estate Ventures | Real_Estate_Investments

Number of real estate ventures that owns 52 office buildings | Real_Estate_Ventures

Number of office buildings owned by 15 Real Estate Ventures | Buildings

Net rentable square feet of 52 office buildings owned the 15 Real Estate Ventures | sqft

6.7

Number of real estate ventures that owns undeveloped land | Real_Estate_Ventures

Area of undeveloped parcels of land (in acres) owned by a Real Estate Venture | A

Number of real estate ventures developed hotel property | Real_Estate_Ventures

Number of rooms in a hotel property developed by one Real Estate Venture | Room

137

Minimum ownership interest in unconsolidated Real Estate Ventures

20.00%

Maximum ownership interest in unconsolidated Real Estate Ventures

65.00%

Company's ownership percentage in the Real Estate Venture

25.00%

Percentage of interest acquired in partnerships by other partner

75.00%

Interest acquired in partnerships, Number | Buildings

Number of office buildings owned | Buildings

Real estate venture debt

$ 745,830

G&I Interchange Office LLC (DRA — N. PA) [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Company's ownership percentage in the Real Estate Venture

^[1],[2]

20.00%

Sale of ownership in properties

80.00%

Real estate venture debt

^[2]

$ 181,967

Two Tower Bridge [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Company's ownership percentage in the Real Estate Venture

^[1],[3]

35.00%

Real estate venture debt

^[3]

$ 13,482

Two Tower Bridge [Member] | Mortgage Maturing May 2013 [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Debt instrument stated interest rate

5.72%

Real estate venture debt

$ 10,100

Debt Instrument, Interest Rate, Effective Percentage Rate Range, Minimum

0.00%

Debt Instrument, Interest Rate, Effective Percentage Rate Range, Maximum

1.00%

Two Tower Bridge [Member] | Mortgage Maturing May 2013 [Member] | Minimum [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Debt Instrument, Term

3 years

Two Tower Bridge [Member] | Mortgage Maturing May 2013 [Member] | Maximum [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Debt Instrument, Term

10 years

Two Tower Bridge [Member] | Municipal and state borrowings [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Real estate venture debt

$ 3,400

Seven Tower Bridge [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Company's ownership percentage in the Real Estate Venture

^[1],[4]

20.00%

Debt instrument stated interest rate

3.00%

Real estate venture debt

^[4]

$ 11,182

Debt Instrument, Number of Fixed Rate Mortgages | Fixed_Rate_Mortgages

Seven Tower Bridge [Member] | Mortgage One and Two [Member] | Fixed Interest Rate Through February 2012 [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Debt instrument stated interest rate

4.00%

Seven Tower Bridge [Member] | Mortgage One and Two [Member] | Fixed Interest Rate Through February 2013 [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Debt instrument stated interest rate

5.00%

Seven Tower Bridge [Member] | Mortgage Maturing February 2014 [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Debt instrument stated interest rate

4.00%

Seven Tower Bridge [Member] | Secured Debt [Member] | Mortgage One Maturing February 2013 [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Real estate venture debt

$ 7,000

Seven Tower Bridge [Member] | Secured Debt [Member] | Mortgage Two Maturing February 2013 [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Real estate venture debt

1,000

Seven Tower Bridge [Member] | Secured Debt [Member] | Mortgage Maturing February 2014 [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Real estate venture debt

2,000

Seven Tower Bridge [Member] | Line of Credit [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Real estate venture debt

1,200

Equity Method Investment Summarized Financial Information Debt, Maximum Borrowings

$ 1,300

Coppell Associates [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Company's ownership percentage in the Real Estate Venture

^[1],[5],[6]

50.00%

Real estate venture debt

^[5],[6]

$ 18,060

Debt Instrument, Number of Fixed Rate Mortgages | Fixed_Rate_Mortgages

Debt Instrument, Blended Rate

5.89%

Coppell Associates [Member] | Senior Mortgage [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Debt instrument stated interest rate

5.75%

Real estate venture debt

$ 16,400

Coppell Associates [Member] | Junior Mortgage [Member]

Investment in Unconsolidated Ventures (Textuals) [Abstract]

Debt instrument stated interest rate

6.89%

Real estate venture debt

$ 1,600

[1]	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.
[2]	Proceeds received by the Company from the sale of an 80% ownership stake in the properties exceeded the historical cost of those properties. Accordingly, no investment in the real estate venture was reflected on the balance sheet at period end.
[3]	Consists of a $10.1 million fixed rate mortgage with a 5.72% interest rate and May 2013 maturity date; also includes $3.4 million municipal and state borrowings with nominal interest rates (0 — 1%) and maturity dates from 3 to 10 years.
[4]	Comprised of two fixed rate mortgages: $7.0 million and $1.0 million. Both mature in February 2013 and accrue interest at a fixed rate of 4% through February 2012, and 5% through February 2013. The total loan amount of $11.2 million as presented above also includes a 3% fixed rate loan (interest only through maturity) with a balance of $1.2 million as of December 31, 2011. This loan can be increased up to $1.3 million through its maturity date of September 2025. The remaining $2.0 million of the total amount features a 4% fixed rate with interest only through its maturity date of February 2014.
[5]	As a result of the adoption of the new accounting standard for the consolidation of variable interest entities, the Company deconsolidated these three real estate ventures as of January 1, 2010.
[6]	Comprised of two fixed rate mortgages: a senior fixed rate note of $16.4 million at 5.75% that matures in March 2016 and a junior fixed rate note of $1.6 million at 6.89% that matures in December 2013; 5.89% is the blended rate.

Investment in Unconsolidated Ventures (Company's Investment in Real Estate Ventures and the Company's Share of the Real Estate Ventures' Income (Loss)) (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Dec. 20, 2011

Nov. 30, 2010

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

25.00%

Company's share of equity (Company's basis)

$ 115,807

$ 84,372

Company's share of income (Company's basis)

3,775

$ 5,305

$ 4,069

Real Estate Venture Debt at 100%

$ 745,830

Debt Instrument Interest Rates Effective Percentage

LIBOR plus 0.725

Broadmoor Austin Associates [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1]

50.00%

Company's share of equity (Company's basis)

$ 66,150

Company's share of income (Company's basis)

197

Real Estate Venture Debt at 100%

$ 66,810

Current Interest Rate

7.04%

Brandywine - Al Venture [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

50.00%

^[1],[2]

50.00%

Company's share of equity (Company's basis)

^[2]

$ 24,670

Company's share of income (Company's basis)

^[2]

(278)

Real Estate Venture Debt at 100%

^[2]

$ 68,000

Macquarie BDN Christina LLC [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1]

20.00%

Company's share of equity (Company's basis)

$ 6,168

Company's share of income (Company's basis)

875

Real Estate Venture Debt at 100%

$ 60,000

Current Interest Rate

4.50%

One Commerce Square [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1],[3]

25.00%

Company's share of equity (Company's basis)

^[3]

$ 5,100

Company's share of income (Company's basis)

^[3]

242

Real Estate Venture Debt at 100%

^[3]

$ 128,529

Current Interest Rate

^[3]

5.67%

Brandywine 1919 Ventures [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1],[4]

50.00%

Company's share of equity (Company's basis)

^[4]

$ 4,882

Company's share of income (Company's basis)

^[4]

Real Estate Venture Debt at 100%

^[4]

$ 0

Two Commerce Square [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1],[3]

25.00%

Company's share of equity (Company's basis)

^[3]

$ 3,415

Company's share of income (Company's basis)

^[3]

224

Real Estate Venture Debt at 100%

^[3]

$ 107,112

Current Interest Rate

^[3]

6.30%

1000 Chesterbrook Blvd. [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1]

50.00%

Company's share of equity (Company's basis)

$ 1,745

Company's share of income (Company's basis)

245

Real Estate Venture Debt at 100%

$ 26,000

Current Interest Rate

4.75%

Four Tower Bridge [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1],[5]

65.00%

Company's share of equity (Company's basis)

^[5]

$ 1,360

Company's share of income (Company's basis)

^[5]

702

Real Estate Venture Debt at 100%

^[5]

$ 10,870

Current Interest Rate

^[5]

5.20%

G&I Interchange Office LLC (DRA — N. PA) [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1],[6]

20.00%

Company's share of equity (Company's basis)

^[6]

$ 1,239

Company's share of income (Company's basis)

^[6]

Real Estate Venture Debt at 100%

^[6]

$ 181,967

Current Interest Rate

^[6]

5.78%

Residence Inn Tower Bridge [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1]

50.00%

Company's share of equity (Company's basis)

$ 481

Company's share of income (Company's basis)

433

Real Estate Venture Debt at 100%

$ 14,261

Current Interest Rate

5.63%

PJP VII [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1]

25.00%

Company's share of equity (Company's basis)

$ 472

Company's share of income (Company's basis)

190

Real Estate Venture Debt at 100%

$ 8,072

Debt Instrument Interest Rates Effective Percentage

L+1.55%

PJP V [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1]

25.00%

Company's share of equity (Company's basis)

$ 361

Company's share of income (Company's basis)

116

Real Estate Venture Debt at 100%

$ 5,789

Current Interest Rate

6.47%

PJP II [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1]

30.00%

Company's share of equity (Company's basis)

$ 300

Company's share of income (Company's basis)

138

Real Estate Venture Debt at 100%

$ 4,263

Current Interest Rate

6.12%

Six Tower Bridge [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1],[5]

63.00%

Company's share of equity (Company's basis)

^[5]

$ 201

Company's share of income (Company's basis)

^[5]

126

Real Estate Venture Debt at 100%

^[5]

$ 12,599

Current Interest Rate

^[5]

7.79%

Two Tower Bridge [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1],[7]

35.00%

Company's share of equity (Company's basis)

^[7]

$ 134

Company's share of income (Company's basis)

^[7]

(364)

Real Estate Venture Debt at 100%

^[7]

$ 13,482

Seven Tower Bridge [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1],[8]

20.00%

Company's share of equity (Company's basis)

^[8]

$ 105

Company's share of income (Company's basis)

^[8]

Real Estate Venture Debt at 100%

^[8]

$ 11,182

PJP VI [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1]

25.00%

Company's share of equity (Company's basis)

$ 31

Company's share of income (Company's basis)

Real Estate Venture Debt at 100%

$ 8,834

Current Interest Rate

6.08%

Eight Tower Bridge [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1]

3.40%

Company's share of equity (Company's basis)

$ 0

Company's share of income (Company's basis)

583

Real Estate Venture Debt at 100%

$ 0

Coppell Associates [Member]

Schedule of Equity Method Investments [Line Items]

Company's ownership percentage in the Real Estate Venture

^[1],[5],[9]

50.00%

Company's share of equity (Company's basis)

^[5],[9]

$ (1,007)

Company's share of income (Company's basis)

^[5],[9]

(139)

Real Estate Venture Debt at 100%

^[5],[9]

18,060

Five Tower Bridge [Member]

Schedule of Equity Method Investments [Line Items]

Company's share of equity (Company's basis)

Company's share of income (Company's basis)

Invesco, L.P. [Member]

Schedule of Equity Method Investments [Line Items]

Company's share of equity (Company's basis)

Company's share of income (Company's basis)

$ 282

[1]	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.
[2]	See Note 3 for related discussion about the Brandywine-AI Venture, LLC formation.
[3]
[4]	See Note 3 for related discussion about the Brandywine 1919 Market Ventures formation.
[5]	As a result of the adoption of the new accounting standard for the consolidation of variable interest entities, the Company deconsolidated these three real estate ventures as of January 1, 2010.
[6]	Proceeds received by the Company from the sale of an 80% ownership stake in the properties exceeded the historical cost of those properties. Accordingly, no investment in the real estate venture was reflected on the balance sheet at period end.
[7]	Consists of a $10.1 million fixed rate mortgage with a 5.72% interest rate and May 2013 maturity date; also includes $3.4 million municipal and state borrowings with nominal interest rates (0 — 1%) and maturity dates from 3 to 10 years.
[8]	Comprised of two fixed rate mortgages: $7.0 million and $1.0 million. Both mature in February 2013 and accrue interest at a fixed rate of 4% through February 2012, and 5% through February 2013. The total loan amount of $11.2 million as presented above also includes a 3% fixed rate loan (interest only through maturity) with a balance of $1.2 million as of December 31, 2011. This loan can be increased up to $1.3 million through its maturity date of September 2025. The remaining $2.0 million of the total amount features a 4% fixed rate with interest only through its maturity date of February 2014.
[9]	Comprised of two fixed rate mortgages: a senior fixed rate note of $16.4 million at 5.75% that matures in March 2016 and a junior fixed rate note of $1.6 million at 6.89% that matures in December 2013; 5.89% is the blended rate.

Investment in Unconsolidated Ventures (Financial Position of Unconsolidated Real Estate Ventures) (Details) - USD ($) $ in Thousands	Dec. 31, 2011	Dec. 31, 2010
Financial position of the Real Estate Ventures
Debt	$ (745,830)
Company's share of equity (Company's basis)	115,807	$ 84,372
Unconsolidated real estate ventures [Member]
Financial position of the Real Estate Ventures
Net property	(846,643)	(804,705)
Other Assets	(110,520)	(105,576)
Other Liabilities	(48,798)	(44,509)
Debt	(745,830)	(748,387)
Equity	162,535	117,385
Company's share of equity (Company's basis)	$ 115,807	$ 84,372

Investment in Unconsolidated Ventures (Summary of Results of Operations of Unconsolidated Real Estate Ventures) (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Summary of results of operations of Real Estate Ventures

Company's share of income (Company's basis)

$ 3,775

$ 5,305

$ 4,069

Unconsolidated real estate ventures [Member]

Summary of results of operations of Real Estate Ventures

Revenue

145,867

^[1]

118,923

^[1]

105,236

Operating expenses

63,715

^[1]

44,942

^[1]

38,691

Interest expense, net

42,032

^[1]

37,505

^[1]

30,858

Depreciation and amortization

39,172

^[1]

32,703

^[1]

36,700

Net income

948

^[1]

3,773

^[1]

(1,012)

Company's share of income (Company's basis)

3,775

^[1]

$ 5,305

^[1]

$ 4,069

Guaranteed repayment of loans on behalf of a certain Real Estate Venture

$ 700

[1]	Includes the three real estate ventures that were deconsolidated upon the adoption of the accounting standard for the consolidation of VIEs on January 1, 2010.

- Definition

The amount of net income (loss) reported by an equity method investment of the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 18
-Subparagraph f
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 18
-Paragraph 20
-Subparagraph d
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph bb
-Article 1

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph w
-Article 1

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 4
-Section 08
-Paragraph g
-Subparagraph 1, 2

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(g))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33912-111571

+ Details

- Definition

This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 18
-Paragraph 19
-Subparagraph c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 18
-Paragraph 6
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 03
-Paragraph 9

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.12)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6382870&loc=d3e33749-111570

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 11
-Article 7

+ Details

Investment in Unconsolidated Ventures (Aggregate Principal Payments of Recourse and Non-recourse Debt Payable to Third-parties) (Details) $ in Thousands	Dec. 31, 2011 USD ($)
Long-term Debt, aggregate principal payments of recourse and non-recourse debt payable to third-parties [Abstract]
2011	$ 476,889
2012	66,806
2013	254,787
2014	327,225
2015	347,065
Thereafter	927,730
Long-term Debt, aggregate principal payments of recourse and non-recourse debt payable to third-parties	745,830
Equity Method Investments [Member]
Long-term Debt, aggregate principal payments of recourse and non-recourse debt payable to third-parties [Abstract]
2011	24,228
2012	143,705
2013	13,809
2014	306,051
2015	97,215
Thereafter	$ 160,822

Deferred Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2011	Dec. 31, 2010
Components of Deferred Costs Net [Abstract]
Leasing Costs, Total Cost	$ 140,772	$ 123,724
Financing Costs, Total Cost	38,929	37,257
Total Cost	179,701	160,981
Leasing Costs, Accumulated Amortization	(50,990)	(43,930)
Financing Costs, Accumulated Amortization	(13,349)	(10,934)
Total, Accumulated Amortization	(64,339)	(54,864)
Leasing Costs, Deferred Costs, net	89,782	79,794
Financing Costs, Deferred Costs, net	25,580	26,323
Deferred Costs	$ 115,362	$ 106,117

Deferred Costs (Details Textuals) - USD ($) $ in Millions	12 Months Ended
Deferred Costs (Details Textuals) - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Deferred Costs (Textuals) [Abstract]
Capitalized internal direct leasing costs	$ 6.6	$ 6.2	$ 5.3

Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Finite-Lived Intangible Assets [Line Items]
Intangible liabilities written off through accelerated amortization	$ 200		$ 400
Intangible assets
Total Cost	176,983	$ 222,160
Accumulated Amortization	(106,468)	(124,698)
Intangibles, net	70,515	97,462
Below market leases acquired	35,106	29,233
Leases, Acquired-in-Place [Member]
Intangible assets
Total Cost	91,426	108,456
Accumulated Amortization	(55,498)	(63,010)
Intangibles, net	35,928	45,446
Customer Relationships [Member]
Intangible assets
Total Cost	72,813	95,385
Accumulated Amortization	(45,114)	(52,113)
Intangibles, net	27,699	43,272
Above market tenant leases acquired [Member]
Intangible assets
Total Cost	12,744	18,319
Accumulated Amortization	(5,856)	(9,575)
Intangibles, net	6,888	8,744
Below market ground lease acquired [Member]
Intangible assets
Total Cost	75,685	67,198
Accumulated Amortization	(40,579)	(37,965)
Intangibles, net	35,106	29,233
Tenant Move-Outs Prior to End of the Lease Term [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets written off through accelerated amortization	$ 7,400	$ 1,500	$ 2,400

Intangible Assets (Details 1) $ in Thousands	12 Months Ended
Intangible Assets (Details 1) $ in Thousands	Dec. 31, 2011 USD ($)
Assets, Total [Member]
Annual amortization of intangible assets and liabilities
2012	$ 20,457
2013	12,457
2014	9,606
2015	7,207
2016	4,565
Thereafter	16,223
Total	70,515
Liabilities, Total [Member]
Annual amortization of intangible assets and liabilities
2012	6,826
2013	6,312
2014	4,745
2015	2,597
2016	1,704
Thereafter	12,922
Total	$ 35,106

Debt Obligations (Details) - USD ($)
$ in Thousands

Dec. 31, 2011

Mar. 31, 2011

Dec. 31, 2010

Consolidated debt obligations

Net unamortized premiums/(discounts)

$ (6,507)

Less: unamortized exchangeable debt discount

$ (900)

Total mortgage indebtedness

511,061

$ 711,789

Total Debt Obligations

$ 2,393,995

Effective interest rate

5.50%

Effective interest rate

LIBOR plus 0.725

Secured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 512,391

$ 712,246

Net unamortized premiums/(discounts)

(1,330)

(457)

Total mortgage indebtedness

511,061

711,789

Unsecured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

1,888,111

1,722,326

Less: unamortized exchangeable debt discount

(906)

Less: unamortized fixed-rate debt discounts, net

(5,177)

(2,763)

Total unsecured indebtedness

1,882,934

1,718,657

Total Debt Obligations

2,393,995

2,430,446

$345.0M 3.875% Guaranteed Exchangeable Notes due 2026 [Member]

Consolidated debt obligations

Long-term Debt, Gross

59,800

$345.0M 3.875% Guaranteed Exchangeable Notes due 2026 [Member] | Unsecured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 0

59,835

Effective interest rate

^[1]

5.50%

Debt Instrument Maturity Dates

Oct-11

Bank Term Loan [Member] | Unsecured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 37,500

183,000

Effective interest rate

^[2]

LIBOR+0.80%

Debt Instrument Maturity Dates

Jun-12

Credit Facility [Member] | Unsecured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 275,500

183,000

Effective interest rate

^[2]

LIBOR+0.725%

Debt Instrument Maturity Dates

Jun-12

$300.0M 5.750% Guaranteed Notes due 2012 [Member] | Unsecured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 151,491

175,200

Effective interest rate

5.73%

Debt Instrument Maturity Dates

Apr-12

$250.0M 5.400% Guaranteed Notes due 2014 [Member] | Unsecured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 242,681

242,681

Effective interest rate

5.53%

Debt Instrument Maturity Dates

Nov-14

$250.0M 7.500% Guaranteed Notes due 2015 [Member] | Unsecured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 227,329

250,000

Effective interest rate

7.77%

Debt Instrument Maturity Dates

May-15

$250.0M 6.000% Guaranteed Notes due 2016 [Member] | Unsecured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 250,000

250,000

Effective interest rate

5.95%

Debt Instrument Maturity Dates

Apr-16

$300.0M 5.700% Guaranteed Notes due 2017 [Member] | Unsecured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 300,000

300,000

Effective interest rate

5.68%

Debt Instrument Maturity Dates

May-17

$325.0M 4.950% Guaranteed Notes due 2018 [Member] | Unsecured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 325,000

Effective interest rate

5.14%

Debt Instrument Maturity Dates

Apr-18

Indenture IA (Preferred Trust I) [Member] | Unsecured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 27,062

27,062

Effective interest rate

2.75%

Debt Instrument Maturity Dates

Mar-35

Indenture IB (Preferred Trust I) [Member] | Unsecured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 25,774

25,774

Effective interest rate

3.30%

Debt Instrument Maturity Dates

Apr-35

Indenture II (Preferred Trust II) [Member] | Unsecured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 25,774

25,774

Effective interest rate

LIBOR+1.25%

Debt Instrument Maturity Dates

Jul-35

Arboretum I, II, III & V [Member] | Secured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 0

20,386

Effective interest rate

^[3]

7.59%

Debt Instrument Maturity Dates

Jul-11

Midlantic Drive/Lenox Drive/DCC I [Member] | Secured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 0

56,514

Effective interest rate

^[4]

8.05%

Debt Instrument Maturity Dates

Oct-11

Research Office Center [Member] | Secured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 0

39,145

Effective interest rate

^[5],[6]

5.30%

Debt Instrument Maturity Dates

Oct-11

Concord Airport Plaza [Member] | Secured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 0

34,494

Effective interest rate

^[6],[7]

5.55%

Debt Instrument Maturity Dates

Jan-12

Newtown Square/Berwyn Park/Libertyview [Member] | Secured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 56,538

58,102

Effective interest rate

7.25%

Debt Instrument Maturity Dates

May-13

Southpoint III [Member] | Secured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 1,887

2,597

Effective interest rate

7.75%

Debt Instrument Maturity Dates

Apr-14

Tysons Corner [Member] | Secured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 94,882

96,507

Effective interest rate

^[6]

5.36%

Debt Instrument Maturity Dates

Aug-15

Two Logan Square [Member] | Secured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 89,800

89,800

Effective interest rate

7.57%

Debt Instrument Maturity Dates

Apr-16

One Logan Square [Member] | Secured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 0

60,000

Effective interest rate

^[8]

4.50%

Debt Instrument Maturity Dates

Jul-16

Fairview Eleven Tower [Member] | Secured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 22,000

Effective interest rate

4.25%

Debt Instrument Maturity Dates

Jan-17

IRS Philadelphia Campus [Member] | Secured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 202,905

208,366

Effective interest rate

7.00%

Debt Instrument Maturity Dates

Sep-30

Cira South Garage [Member] | Secured Debt [Member]

Consolidated debt obligations

Long-term Debt, Gross

$ 44,379

$ 46,335

Effective interest rate

7.12%

Debt Instrument Maturity Dates

Sep-30

[1]	On October 20, 2011, holders representing $59.5 million of the outstanding Exchangeable Notes exercised their right to cause the Company to redeem their notes at par plus accrued and unpaid interest leaving an outstanding balance of $0.4 million. On December 8, 2011, the Company redeemed the remaining balance of the Exchangeable Notes pursuant to its right under the indenture agreement (see related discussion below).
[2]	On March 31, 2011, the maturity dates of the Bank Term Loan and the Credit Facility were extended to June 29, 2012 from June 29, 2011. On June 29, 2011, the Company paid a total extension fee amounting to $1.2 million which is equal to 15 basis points of the outstanding principal balance of the Bank Term Loan and of the committed amount under the Credit Facility. The extension of the maturity dates was at the Company's option under the Bank Term Loan and the Credit Facility agreements. There were no changes in the terms and conditions of the loan agreements as a result of the maturity date extensions. On December 15, 2011, the Company entered into binding agreements for lender commitments related a new $600.0 million four -year unsecured credit facility (the "New Credit Facility") and three unsecured term loans in the same aggregate amount of $600.0 million (collectively, the “New Term Loans”), consisting of a $150.0 million three-year loan, a $250.0 million four-year loan and a $200.0 million seven-year loan. Please see below for a related discussion regarding the New Credit Facility and Term Loans
[3]	On April 1, 2011, the Company prepaid the remaining balance of the loan without penalty.
[4]	On June 3, 2011, the Company prepaid the remaining balance of the loan without penalty.
[5]	On June 30, 2011, the Company prepaid the remaining balance of the loan without penalty. The unamortized fixed-rate debt premium of $0.3 million related to this loan was included as part of the gain (loss) on early extinguishment of debt in the Company's consolidated statement of operations during the current year.
[6]	These loans were assumed upon acquisition of the related properties. The interest rates reflect the market rate at the time of acquisition.
[7]	On September 1, 2011, the Company prepaid the remaining balance of the loan without penalty. The unamortized fixed-rate debt premium of $0.2 million related to this loan was included as part of the gain (loss) on early extinguishment of debt in the Company's consolidated statement of operations during the year.
[8]	This mortgage was subject to an interest rate floor of 4.50% on a monthly basis. On July 11, 2011, the Company prepaid the balance of the loan without penalty.

Debt Obligations (Details 1) $ in Thousands	12 Months Ended
Debt Obligations (Details 1) $ in Thousands	Dec. 31, 2011 USD ($)
Schedule of principal payments of debt obligations
Repurchase Amount	$ 109,724
Principal	106,215
Loss	3,264
Deferred Financing Amortization	152
2011 3.75% Notes [Member]
Schedule of principal payments of debt obligations
Repurchase Amount	59,835
Principal	59,835
Loss	0
Deferred Financing Amortization	$ 0
Debt instrument stated interest rate	3.875%
2012 5.750% Notes [Member]
Schedule of principal payments of debt obligations
Repurchase Amount	$ 24,749
Principal	23,709
Loss	868
Deferred Financing Amortization	$ 32
Debt instrument stated interest rate	5.75%
2015 7.500% Notes [Member]
Schedule of principal payments of debt obligations
Repurchase Amount	$ 25,140
Principal	22,671
Loss	2,396
Deferred Financing Amortization	$ 120
Debt instrument stated interest rate	7.50%

Debt Obligations (Details 2) $ in Thousands	Dec. 31, 2011 USD ($)
Summary of debt repurchases
2012	$ 476,889
2013	66,806
2014	254,787
2015	327,225
2016	347,065
Thereafter	927,730
Total principal payments	2,400,502
Net unamortized premiums/(discounts)	(6,507)
Outstanding indebtedness	$ 2,393,995

Debt Obligations (Details Textuals) - USD ($)		12 Months Ended
Debt Obligations (Details Textuals) - USD ($)	Jun. 29, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 15, 2011	Oct. 20, 2011	Sep. 30, 2011	Mar. 31, 2011	Dec. 31, 2009
Debt obligations (Textuals)
Properties encumbered mortgage indebtedness carrying value, net		$ 678,000,000	$ 989,800,000
Secured Debt [Member]
Debt obligations (Textuals)
Weighted average effective interest rate		6.72%	6.59%					6.45%
Unsecured Debt [Member]
Debt obligations (Textuals)
Debt instrument, face amount				$ 600,000,000
Borrowings under the credit facility		$ 275,500,000
Unused availability under the Credit Facility		$ 322,000,000
Weighted average effective interest rate		0.99%	1.03%
Weighted average interest rate on the Credit Facility		1.01%	1.02%
Letter of Credit [Member] \| Unsecured Debt [Member]
Debt obligations (Textuals)
Borrowings under the credit facility		$ 2,500,000
Credit Facility [Member]
Debt obligations (Textuals)
Maximum amount by which the Company may increase its credit facility				600,000,000
Option for additional borrowings subject to customary conditions and limitations				$ 200,000,000
Bank Term Loan and the Credit Facility [Member]
Debt obligations (Textuals)
Extended Maturity date		Jun. 29, 2012
Debt Instrument, Extension Fee Amount	$ 1,200,000
Basis points of the outstanding principal balance related to debt extension fee	1.50%
$345.0M 3.875% Guaranteed Exchangeable Notes due 2026 [Member]
Debt obligations (Textuals)
Debt instrument stated interest rate		3.875%
Carrying amount of the equity component		$ 24,400,000
$345.0M 3.875% Guaranteed Exchangeable Notes due 2026 [Member] \| Unsecured Debt [Member]
Debt obligations (Textuals)
Debt instrument, face amount		$ 345,000,000
Initial Maturity Date						Oct. 20, 2011
Guaranteed Exchangeable Notes tendered and accepted for purchase					$ 59,500,000
Outstanding balance remaining after redeem notes at par plus accrued and unpaid interest					$ 400,000
Debt instrument stated interest rate		3.875%
$300.0M 5.750% Guaranteed Notes due 2012 [Member] \| Unsecured Debt [Member]
Debt obligations (Textuals)
Debt instrument, face amount		$ 300,000,000
Debt instrument stated interest rate		5.75%
$250.0M 5.400% Guaranteed Notes due 2014 [Member] \| Unsecured Debt [Member]
Debt obligations (Textuals)
Debt instrument, face amount		$ 250,000,000
Debt instrument stated interest rate		5.40%
$250.0M 7.500% Guaranteed Notes due 2015 [Member] \| Unsecured Debt [Member]
Debt obligations (Textuals)
Debt instrument, face amount		$ 250,000,000
Debt instrument stated interest rate		7.50%
$250.0M 6.000% Guaranteed Notes due 2016 [Member] \| Unsecured Debt [Member]
Debt obligations (Textuals)
Debt instrument, face amount		$ 250,000,000
Debt instrument stated interest rate		6.00%
$300.0M 5.700% Guaranteed Notes due 2017 [Member] \| Unsecured Debt [Member]
Debt obligations (Textuals)
Debt instrument, face amount		$ 300,000,000
Debt instrument stated interest rate		5.70%
$325.0M 4.950% Guaranteed Notes due 2018 [Member] \| Unsecured Debt [Member]
Debt obligations (Textuals)
Debt instrument, face amount		$ 325,000,000
Debt instrument stated interest rate		4.95%					4.95%
One Logan Square [Member] \| Secured Debt [Member]
Debt obligations (Textuals)
Interest rate floor on a monthly basis		4.50%

Debt Obligations (Details Textuals 1) - USD ($)

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Dec. 15, 2011

Sep. 30, 2011

Jun. 30, 2011

Debt Instrument [Line Items]

Proceeds from Issuance of First Mortgage Bond

$ 0

$ 256,104,000

$ 149,800,000

Debt obligations (Additional) (Textuals)

Repurchased outstanding unsecured notes

$ 106,215,000

Less: unamortized exchangeable debt discount

$ 900,000

Debt Instrument, Interest Rate, Effective Percentage

5.50%

Contractual coupon interest recognized on exchangeable debt

$ 1,900,000

$ 3,200,000

Interest on amortization of debt discount

$ 900,000

1,600,000

Debt discount write-offs resulting from debt repurchases

2,000,000

Research Office Center [Member]

Debt Instrument [Line Items]

Unamortized fixed-rate debt premium

$ 300,000

Debt obligations (Additional) (Textuals)

Debt Instrument, Unamortized Premium

$ 300,000

Concord Airport Plaza [Member]

Debt Instrument [Line Items]

Unamortized fixed-rate debt premium

$ 200,000

Debt obligations (Additional) (Textuals)

Debt Instrument, Unamortized Premium

$ 200,000

$345.0M 3.875% Guaranteed Exchangeable Notes due 2026 [Member]

Debt Instrument [Line Items]

Debt instrument stated interest rate

3.875%

Debt obligations (Additional) (Textuals)

Long-term Debt, Gross

$ 59,800,000

Unsecured Debt [Member]

Debt Instrument [Line Items]

Debt instrument, face amount

$ 600,000,000

Senior unsecured notes discounts

5,177,000

2,763,000

Debt obligations (Additional) (Textuals)

Long-term Debt, Gross

1,888,111,000

1,722,326,000

Less: unamortized exchangeable debt discount

906,000

Unsecured Debt [Member] | $345.0M 3.875% Guaranteed Exchangeable Notes due 2026 [Member]

Debt Instrument [Line Items]

Debt instrument, face amount

$ 345,000,000

Debt instrument stated interest rate

3.875%

Debt obligations (Additional) (Textuals)

Long-term Debt, Gross

$ 0

$ 59,835,000

Debt Instrument, Interest Rate, Effective Percentage

^[1]

5.50%

[1]

Debt Obligations (Details Textuals 2)			12 Months Ended
Debt Obligations (Details Textuals 2)	Dec. 15, 2011 USD ($)	Aug. 26, 2010 USD ($)	Dec. 31, 2011 USD ($) Years	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Sep. 10, 2010	Jun. 29, 2009 USD ($)
Debt Instrument [Line Items]
Gross proceeds from Issuance of First Mortgage Bond		$ 254,000,000
Forward financing commitment							$ 256,500,000
Debt Related Commitment Fees and Debt Issuance Costs		$ 17,700,000
Amortization of deferred financing costs			$ 4,991,000	$ 3,770,000	$ 5,864,000
Amortization of life of the loan using effective interest rate method in years \| Years			20
Debt related commitment fees reduced by refund resulting from overpayment			$ 16,000,000
Refund of deferred financing costs related to forward commitment			0	$ 1,659,000	$ 0
Other related transaction costs included in total financing costs			$ 3,800,000
Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity	$ 600,000,000
Debt Instrument, Term	4 years
Debt instrument, basis spread on variable rate			1.50%
Option to extend Term Loan			1 year
Three-year Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Term	3 years
Debt instrument, basis spread on variable rate			1.75%
Option to extend Term Loan			1 year
Four-year Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Term	4 years
Debt instrument, basis spread on variable rate			1.75%
Option to extend Term Loan			1 year
Seven-year Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Term	7 years
Declining prepayment penalty in year one			3.00%
Declining prepayment penalty in year two			2.00%
Declining prepayment penalty in year three			1.00%
Debt instrument, basis spread on variable rate			1.90%
Derivative, Average Fixed Interest Rate			3.623%
Three and Four-year Term Loan [Member]
Debt Instrument [Line Items]
Notional amount of interest rate cash flow hedge derivatives			$ 300,000,000
Derivative, lower fixed interest rate range			2.47%
Derivative, higher fixed interest rate range			2.91%
Derivative, lower remaining maturity range			3 years
Derivative, higher remaining maturity range			5 years
$345.0M 3.875% Guaranteed Exchangeable Notes due 2026 [Member]
Debt Instrument [Line Items]
Debt instrument stated interest rate			3.875%
IRS Philadelphia Campus [Member]
Debt Instrument [Line Items]
Forward financing commitment							209,700,000
Cira South Garage [Member]
Debt Instrument [Line Items]
Forward financing commitment							46,800,000
IRS Philadelphia Campus and Cira South Garage [Member]
Debt Instrument [Line Items]
Debt instrument stated interest rate						5.93%
Loans proceeds withheld pending completion							$ 2,500,000
Proceeds from mortgage notes payable retained by lender and included in other receivables			$ 2,100,000
Amortization of deferred financing costs			$ 19,900,000
Credit Facility Decemeber 2011 [Member] \| Federal Funds Rate [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			0.50%
Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 600,000,000
Repayments of Credit Facility borrowings	600,000,000
Repayments of unsecured notes			$ 275,500,000
Unsecured Debt [Member] \| Three-year Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	150,000,000
Repayments of Credit Facility borrowings	150,000,000
Unsecured Debt [Member] \| Four-year Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	250,000,000
Repayments of Credit Facility borrowings	250,000,000
Unsecured Debt [Member] \| Seven-year Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	200,000,000
Repayments of Credit Facility borrowings	$ 200,000,000
Unsecured Debt [Member] \| $300.0M 5.750% Guaranteed Notes due 2012 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount			300,000,000
Repayments of Credit Facility borrowings			$ 300,000,000
Debt instrument stated interest rate			5.75%
Unsecured Debt [Member] \| $345.0M 3.875% Guaranteed Exchangeable Notes due 2026 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount			$ 345,000,000
Repayments of Credit Facility borrowings			$ 345,000,000
Debt instrument stated interest rate			3.875%

Fair Value of Financial Instruments (Details) - USD ($)
$ in Thousands

Dec. 31, 2011

Dec. 31, 2010

Company's estimates of fair value differ from the carrying amounts

Mortgage payable, net of premiums, Carrying Amount

$ 512,391

$ 712,246

Mortgage payable, net of premiums, Fair Value

545,784

726,348

Unsecured notes payable, net of discounts, Carrying Amount

1,496,501

1,277,716

Unsecured notes payable, net of discounts, Fair Value

1,555,633

1,338,743

Variable rate debt instruments, Carrying Amount

391,610

444,610

Variable rate debt instruments, Fair Value

380,786

432,556

Notes receivable, Carrying Amount

^[1]

31,157

31,216

Notes receivable, Fair Value

$ 32,756

$ 28,921

[1]	For purposes of this disclosure, one of the notes is presented gross of the deferred gain of $12.9 million arising from the sale of the two Trenton properties in 2009 accounted for under the accounting standard for installment sales.

Fair Value of Financial Instruments (Details Textuals) $ in Millions	12 Months Ended
	Dec. 31, 2011 USD ($) Properties	Dec. 31, 2010 Properties	Dec. 31, 2009 Properties
Fair Value of Financial Instruments (Textuals) [Abstract]
Number of properties sold (in properties)	19	19	19
Trenton Properties [Member]
Fair Value of Financial Instruments (Textuals) [Abstract]
Gross deferred gain on sale of properties \| $	$ 12.9
Number of properties sold (in properties)	2

Risk Management and Use of Financial Instruments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Mar. 31, 2011 USD ($)
Risk Management and use of Financial Instruments (Textuals) [Abstract]
Fair value	$ 3,886
Notional Amount	452,836
Accumulated other comprehensive income related to debt offering that will be amortized over the term of the note	$ (6,079)	$ (1,945)
Gain on fair value hedge ineffectiveness			$ 100
No. of tenants accounted for 10% or more of the Company's rents	0	0	0
Unsecured Debt [Member]
Risk Management and use of Financial Instruments (Textuals) [Abstract]
Long-term Debt, Gross	$ 1,888,111	$ 1,722,326
Unsecured Debt [Member] \| $325.0M 4.950% Guaranteed Notes due 2018 [Member]
Risk Management and use of Financial Instruments (Textuals) [Abstract]
Long-term Debt, Gross	$ 325,000	$ 0		$ 325,000
Debt instrument stated interest rate	4.95%			4.95%
Interest Rate Swap [Member]
Risk Management and use of Financial Instruments (Textuals) [Abstract]
Fair value adjustment of the hedge charged to expenses			$ 1,100
Interest Rate Swap [Member] \| Cash Flow Hedging [Member] \| Treasury Lock Agreement [Member]
Risk Management and use of Financial Instruments (Textuals) [Abstract]
Number of Treasury Lock agreements				7
Fair value				$ 600
Notional Amount				$ 230,000
Remaining maturity				7 years
Accumulated other comprehensive income related to debt offering that will be amortized over the term of the note	$ 600
Interest Rate Swap [Member] \| Cash Flow Hedging [Member] \| Treasury Lock Agreement [Member] \| 2.891% Treasury Rate [Member]
Risk Management and use of Financial Instruments (Textuals) [Abstract]
Fixed Interest Rate				2.891%
Interest Rate Swap [Member] \| Cash Flow Hedging [Member] \| Treasury Lock Agreement [Member] \| 2.873% Treasury Rate [Member]
Risk Management and use of Financial Instruments (Textuals) [Abstract]
Fixed Interest Rate				2.873%
Interest Rate Swap [Member] \| Cash Flow Hedging [Member] \| Treasury Lock Agreement [Member] \| 2.858% Treasury Rate [Member]
Risk Management and use of Financial Instruments (Textuals) [Abstract]
Fixed Interest Rate				2.858%

Risk Management and Use of Financial Instruments (Fair Values of Derivative Financial Instruments) (Details)
$ in Thousands

Dec. 31, 2011

USD ($)

Derivatives, Fair Value [Line Items]

Notional Amount

$ 452,836

Fair value

3,886

Interest Rate Swap [Member] | Cash Flow Hedging [Member] | 3.623% Interest Rate Swap Maturing February 1, 2019 [Member]

Derivatives, Fair Value [Line Items]

Notional Amount

$ 200,000

^[1]

Strike

0.03623

^[1]

Fair value

$ 2,820

^[1]

Interest Rate Swap [Member] | Cash Flow Hedging [Member] | 2.702% Interest Rate Swap Maturing February 1, 2016 [Member]

Derivatives, Fair Value [Line Items]

Notional Amount

$ 127,000

^[1]

Strike

0.02702

^[1]

Fair value

$ 340

^[1]

Interest Rate Swap [Member] | Cash Flow Hedging [Member] | 2.470% Interest Rate Swap Maturing February 1, 2015 [Member]

Derivatives, Fair Value [Line Items]

Notional Amount

$ 50,000

^[1]

Strike

0.02470

^[1]

Fair value

$ 65

^[1]

Interest Rate Swap [Member] | Cash Flow Hedging [Member] | 2.513% Interest Rate Swap Maturing May 1, 2015 [Member]

Derivatives, Fair Value [Line Items]

Notional Amount

$ 23,000

^[1]

Strike

0.02513

^[1]

Fair value

$ 27

^[1]

Interest Rate Swap [Member] | Cash Flow Hedging [Member] | 2.750% Interest Rate Swap Maturing September 30, 2017 [Member]

Derivatives, Fair Value [Line Items]

Notional Amount

$ 27,062

^[1]

Strike

0.02750

^[1]

Fair value

$ 244

^[1]

Interest Rate Swap [Member] | Cash Flow Hedging [Member] | 3.300% Interest Rate Swap Maturing January 30, 2021 [Member]

Derivatives, Fair Value [Line Items]

Notional Amount

$ 25,774

^[1]

Strike

0.033

^[1]

Fair value

$ 390

^[1]

[1]	Hedging unsecured variable rate debt.

Discontinued Operations (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

^[1]

Mar. 31, 2011

^[2]

Dec. 31, 2010

Sep. 30, 2010

Jun. 30, 2010

^[1]

Mar. 31, 2010

^[2]

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Revenue:

Rents

$ 480,600

$ 461,101

$ 467,188

Tenant reimbursements

81,236

77,139

76,652

Termination fees

2,993

5,576

3,601

Other

5,440

4,310

3,328

Total revenue

$ 146,609

$ 144,308

$ 144,094

$ 146,794

$ 146,084

$ 140,179

$ 134,191

$ 139,502

581,805

559,956

567,920

Expenses:

Property operating expenses

171,991

167,911

162,940

Real estate taxes

56,230

53,564

56,224

Depreciation and amortization

217,680

210,592

203,572

Total operating expenses

476,093

461,239

451,553

Income from discontinued operations before gain on sale of interests in real estate

1,253

2,659

6,960

Net gain on disposition of discontinued operations

7,264

11,011

1,241

Provision for impairment

(3,700)

Income from discontinued operations

8,517

13,670

4,501

Discontinued Operations [Member]

Revenue:

Rents

3,779

9,363

19,095

Tenant reimbursements

1,198

3,678

8,453

Termination fees

190

Other

(50)

238

Total revenue

4,960

13,301

27,786

Expenses:

Property operating expenses

1,717

4,641

9,884

Real estate taxes

559

1,816

3,769

Depreciation and amortization

1,431

4,185

7,173

Total operating expenses

$ 3,707

$ 10,642

$ 20,826

[1]

[2]

Discontinued Operations (Details Textuals) sqft in Millions	12 Months Ended
Discontinued Operations (Details Textuals) sqft in Millions	Dec. 31, 2011 Properties sqft	Dec. 31, 2010 Properties	Dec. 31, 2009 Properties
Discontinued Operations (Textuals) [Abstract]
Number of properties sold (in properties) \| Properties	19	19	19
Discontinued Operations [Member]
Discontinued Operations (Textuals) [Abstract]
Net rentable square feet of properties sold (in square feet) \| sqft	1.6

Non Controlling Interests in The Parent Company Non Contolling Interests in the Parent Company (Details) - USD ($) $ in Millions	Dec. 31, 2011	Dec. 31, 2010
Non Controlling Interests In The Parent Company (Textuals) [Abstract]
Aggregate amount related to non-controlling interests classified within equity	$ 33.1	$ 128.3
Settlement value of non controlling interest in operating partnership	$ 25.6	$ 115.4

Beneficiaries Equity of The Parent Company (Details) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

^[1]

Mar. 31, 2011

^[2]

Dec. 31, 2010

Sep. 30, 2010

Jun. 30, 2010

^[1]

Mar. 31, 2010

^[2]

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Numerator

Income (loss) from continuing operations, Basic

$ (13,232)

$ (31,276)

$ 3,588

Income (loss) from continuing operations, Diluted

(13,232)

(31,276)

3,588

Net (loss) income from continuing operations attributable to non-controlling interests, Basic

548

820

Net (loss) income from continuing operations attributable to non-controlling interests, Diluted

548

820

Amount allocated to unvested restricted shareholders/unitholders, Basic

(505)

(512)

(279)

Amount allocable to unvested restricted shareholders, Diluted

(505)

(512)

(279)

Preferred share dividends, Basic

(7,992)

Preferred share dividends, Diluted

(7,992)

Loss from continuing operations available to common shareholders, Basic

(21,181)

(38,960)

(4,625)

Loss from continuing operations available to common shareholders, Diluted

(21,181)

(38,960)

(4,625)

Income from discontinued operations

8,517

13,670

4,501

Income from discontinued operations, Diluted

8,517

13,670

4,501

Discontinued operations attributable to non-controlling interests - LP units

(332)

(288)

(91)

Net income (loss) attributable to noncontrolling interest, joint venture partners and income (loss) from discontinued operations, net of tax, attributable to noncontrolling interest

(121)

Discontinued operations attributable to non-controlling interests, diluted

(332)

(288)

(121)

Discontinued operations attributable to common shareholders, Basic

8,185

13,382

4,380

Discontinued operations attributable to common shareholders, Diluted

8,185

13,382

4,380

Net loss attributable to Common Shareholders of Brandywine Realty Trust

(12,996)

(25,578)

(245)

Net loss available to common shareholders, Diluted

$ (12,996)

$ (25,578)

$ (245)

Denominator

Basic weighted average shares outstanding

135,444,424

131,743,275

111,898,045

Contingent securities/Stock based compensation

1,353,246

Weighted-average shares/units outstanding, Diluted

135,444,424

131,743,275

113,251,291

Earnings (loss) per Common Share:

Loss from continuing operations attributable to common shareholders/unitholders, Basic

$ (0.16)

$ (0.29)

$ (0.04)

Loss from continuing operations attributable to common shareholders/unitholders, Diluted

(0.16)

(0.29)

(0.04)

Discontinued operations attributable to common shareholders, Basic

0.06

0.10

0.04

Discontinued operations attributable to common shareholders, Diluted

0.06

0.10

0.04

Net loss attributable to common shareholders/unitholders, Basic

$ (0.05)

$ 0.03

$ (0.06)

$ (0.02)

$ (0.05)

$ (0.06)

$ (0.02)

(0.10)

(0.19)

0.00

Net loss attributable to common shareholders/unitholders, Diluted

$ (0.05)

$ 0.03

$ (0.06)

$ (0.02)

$ (0.05)

$ (0.06)

$ (0.02)

$ (0.10)

$ (0.19)

$ 0.00

[1]

[2]

Beneficiaries Equity of The Parent Company (DetailsTextuals) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Dec. 23, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2004	Dec. 31, 2003	Jan. 19, 2012	Jan. 05, 2012	Dec. 13, 2011	Aug. 05, 2010	May 02, 2006
Class of Stock [Line Items]
Dividends paid for preferred shares		$ 7,992	$ 7,992	$ 7,992
Beneficiaries Equity of The Parent Company (Textuals) [Abstract]
Antidilutive securities excluded from computation of earnings per share		2,698,647	9,902,752	2,809,108
Shares authorized for Equity Offering Program		15,000,000
Maximum percentage of Gross sale price per share, compensation to sales agents		2.00%
Issuance of Common Shares of Beneficial Interest, shares		679,285
Average sales price per share		$ 12.18
Proceeds from Contributions from Parent		$ 8,000
Issuance of Common Shares of Beneficial Interest		$ 8,272	$ 71,981	$ 242,323
Remaining shares available for sales		8,578,447
Common Partnership Units Issued		6,421,553
Common shares capacity restored											3,500,000
Additional shares Expected to be purchased under program		500,000
Class F (2010) Units
Beneficiaries Equity of The Parent Company (Textuals) [Abstract]
Common partnership units issued to the parent company related to redemption	7,111,112
7.50% Series C Preferred Shares
Class of Stock [Line Items]
Dividends paid for preferred shares		$ 900
Percentage of Preferential return		7.50%
Series D Preferred Stock [Member]
Class of Stock [Line Items]
Dividends paid for preferred shares		$ 1,100
Percentage of Preferential return		7.375%
Dividend Declared
Beneficiaries Equity of The Parent Company (Textuals) [Abstract]
Distribution Declared per common partnership unit							$ 0.15
Dividend Paid
Beneficiaries Equity of The Parent Company (Textuals) [Abstract]
Amount of dividend declared								$ 21,500
7.50% Series C Preferred Shares
Class of Stock [Line Items]
Percentage of Preferential return		7.50%	7.50%			7.50%
Proceeds from issuance of redeemable preferred shares (in dollars)						$ 48,100
Preferred shares, shares issued		2,000,000	2,000,000			2,000,000
Preferred shares, redemption price (in dollars per share)		$ 25
Series D Preferred Stock [Member]
Class of Stock [Line Items]
Percentage of Preferential return		7.375%	7.375%		7.375%
Proceeds from issuance of redeemable preferred shares (in dollars)					$ 55,500
Preferred shares, shares issued		2,300,000	2,300,000		2,300,000
Preferred shares, redemption price (in dollars per share)		$ 25.00
Subsidiaries [Member]
Beneficiaries Equity of The Parent Company (Textuals) [Abstract]
Distribution Declared per common partnership unit									$ 0.15
Common partnership units issued to the parent company related to redemption		679,285
Subsidiaries [Member] \| Class F (2010) Units
Beneficiaries Equity of The Parent Company (Textuals) [Abstract]
Partnership units issued for acquisition										7,111,112

Partners Equity of The Operating Partnership (Details) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

^[1]

Mar. 31, 2011

^[2]

Dec. 31, 2010

Sep. 30, 2010

Jun. 30, 2010

^[1]

Mar. 31, 2010

^[2]

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Numerator

Income (loss) from continuing operations, Basic

$ (13,232)

$ (31,276)

$ 3,588

Income (loss) from continuing operations, Diluted

(13,232)

(31,276)

3,588

Net (loss) income from continuing operations attributable to non-controlling interests

548

820

Net (loss) income from continuing operations attributable to non-controlling interests, Diluted

548

820

Amount allocated to unvested restricted shareholders/unitholders, Basic

(505)

(512)

(279)

Amount allocable to unvested restricted unitholders, Diluted

(505)

(512)

(279)

Preferred share dividends, Basic

(7,992)

Preferred share dividends, Diluted

(7,992)

Discontinued operations attributable to common unitholders, Basic

8,517

13,670

4,501

Net loss attributable to Common Shareholders of Brandywine Realty Trust

(12,996)

(25,578)

(245)

Net loss available to common shareholders, Diluted

$ (12,996)

$ (25,578)

$ (245)

Denominator

Total weighted-average units outstanding, Basic

135,444,424

131,743,275

111,898,045

Contingent securities/Stock based compensation

1,353,246

Weighted-average shares/units outstanding, Diluted

135,444,424

131,743,275

113,251,291

Income per Common Partnership Unit:

Loss from continuing operations attributable to common shareholders/unitholders, Basic

$ (0.16)

$ (0.29)

$ (0.04)

Loss from continuing operations attributable to common shareholders/unitholders, Diluted

(0.16)

(0.29)

(0.04)

Discontinued operations attributable to common shareholders, Basic

0.06

0.10

0.04

Discontinued operations attributable to common shareholders, Diluted

0.06

0.10

0.04

Net loss attributable to common shareholders/unitholders, Basic

$ (0.05)

$ 0.03

$ (0.06)

$ (0.02)

$ (0.05)

$ (0.06)

$ (0.02)

(0.10)

(0.19)

0.00

Net loss attributable to common shareholders/unitholders, Diluted

$ (0.05)

$ 0.03

$ (0.06)

$ (0.02)

$ (0.05)

$ (0.06)

$ (0.02)

$ (0.10)

$ (0.19)

$ 0.00

BRANDYWINE OPERATING PARTNERSHIP, L.P.

Numerator

Income (loss) from continuing operations, Basic

$ (13,232)

$ (31,276)

$ 3,588

Income (loss) from continuing operations, Diluted

(13,232)

(31,276)

3,588

Net (loss) income from continuing operations attributable to non-controlling interests

(30)

Net (loss) income from continuing operations attributable to non-controlling interests, Diluted

(30)

Amount allocated to unvested restricted shareholders/unitholders, Basic

(505)

(512)

(279)

Amount allocable to unvested restricted unitholders, Diluted

(505)

(512)

(279)

Preferred share dividends, Basic

(7,992)

Preferred share dividends, Diluted

(7,992)

Loss from continuing operations available to common unitholders, Basic

(21,729)

(39,780)

(4,713)

Loss from continuing operations available to common unit holders, Diluted

(21,729)

(39,780)

(4,713)

Discontinued operations attributable to common unitholders, Basic

8,517

13,670

4,501

Discontinued operations attributable to common unit holders, Diluted

8,517

13,670

4,501

Net loss attributable to Common Shareholders of Brandywine Realty Trust

(13,212)

(26,110)

(212)

Net loss available to common shareholders, Diluted

$ (13,212)

$ (26,110)

$ (212)

Denominator

Total weighted-average units outstanding, Basic

145,118,841

137,454,796

114,712,869

Contingent securities/Stock based compensation

1,353,246

Weighted-average shares/units outstanding, Diluted

145,118,841

137,454,796

116,066,115

Income per Common Partnership Unit:

Loss from continuing operations attributable to common shareholders/unitholders, Basic

$ (0.15)

$ (0.29)

$ (0.04)

Loss from continuing operations attributable to common shareholders/unitholders, Diluted

(0.15)

(0.29)

(0.04)

Discontinued operations attributable to common shareholders, Basic

0.06

0.10

0.04

Discontinued operations attributable to common shareholders, Diluted

0.06

0.10

0.04

Net loss attributable to common shareholders/unitholders, Basic

(0.09)

(0.19)

0.00

Net loss attributable to common shareholders/unitholders, Diluted

$ (0.09)

$ (0.19)

$ 0.00

[1]

[2]

Partners Equity of The Operating Partnership (DetailsTextuals) - USD ($) $ / shares in Units, $ in Millions					12 Months Ended
	Jan. 17, 2012	Dec. 23, 2011	Feb. 27, 2004	Dec. 30, 2003	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Jan. 19, 2012	Dec. 13, 2011	Aug. 05, 2010
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Redeemable limited partnership units potential cash redemption value based on closing market price					$ 9.50	$ 11.65	$ 11.40
Net proceeds contributed by Parent Company					$ 8.0
Issue of shares under Offering Program					679,285
Redemption price of partnership unit										either for an amount, per unit, of cash equal to the market price of one of the Parent Company’s common share (based on the five-day trading average ending on the date of the exchange) or for one of the Parent Company’s common share
Common Partnership Units Issued					6,421,553
Remaining shares available for sales					8,578,447
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Distribution Declared per common partnership unit									$ 0.15
Common partnership units issued to the parent company					679,285
BRANDYWINE OPERATING PARTNERSHIP, L.P. \| 7.375% Series E Preferred Shares
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Preferred units, shares issued			2,300,000		2,300,000	2,300,000
Preferred units, aggregate liquidation preference			$ 57.5
Preferred units, liquidation preference per unit			$ 25
Percentage of Preferential return			7.375%		7.375%	7.375%
BRANDYWINE OPERATING PARTNERSHIP, L.P. \| 7.50% Series D Preferred Shares
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Preferred units, shares issued				2,000,000	2,000,000	2,000,000
Preferred units, aggregate liquidation preference				$ 50.0
Preferred units, liquidation preference per unit				$ 25
Percentage of Preferential return				7.50%	7.50%	7.50%
Class A Units
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Limited partners capital account, units outstanding					2,698,647	2,791,640
Class F (2010) Units
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Common partnership units issued to the parent company		7,111,112
Class F (2010) Units \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Partnership units issued for acquisition										7,111,112
Dividend Declared
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Distribution Declared per common partnership unit								$ 0.15
Dividend Declared \| 7.375% Series E Preferred Shares
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Percentage of Preferential return					7.375%
Dividend Declared \| 7.50% Series D Preferred Shares
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Percentage of Preferential return					7.50%
Dividend Paid \| 7.375% Series E Preferred Shares
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Distributions paid Preferred unitholders	$ 1.1
Dividend Paid \| 7.50% Series D Preferred Shares
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Distributions paid Preferred unitholders	$ 0.9
Dividend Paid \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Distribution Declared for common partnership unitholders								$ 21.5

Share Based Compensation, 401(k) Plan and Deferred Compensation (Option Activity) (Details)	12 Months Ended
	Dec. 31, 2011 USD ($) Years $ / shares shares	Dec. 31, 2010 USD ($) Years $ / shares shares	Dec. 31, 2009 Years $ / shares shares
Option activity
Outstanding at beginning of year, shares \| shares	3,116,611	2,404,567	1,754,648
Granted, shares \| shares	603,241	724,805	676,491
Exercised, shares \| shares	(120,180)
Forfetied/Expired, shares \| shares		(12,761)	(26,572)
Outstanding at end of year, shares \| shares	3,599,672	3,116,611	2,404,567
Vested/Exercisable, shares \| shares	2,287,729	1,384,728	616,119
Outstanding at beginning of year, Weighted Average Exercise Price	$ 14.56	$ 15.48	$ 20.41
Granted, Weighted Average Exercise Price	11.89	11.31	2.91
Forfeited/Expired, Weighted Average Exercise Price		2.91	20.61
Exercised, Weighted Average Exercise Price	2.91
Outstanding at end of year, Weighted Average Exercise Price	14.50	14.56	15.48
Vested/Exercisable at end of period, Weighted Average Exercise Price	$ 17.01	$ 17.63	$ 20.03
Outstanding at beginning of year, Weighted Average Remaining Contractual Term \| Years	7.81	8.38	8.77
Granted, Weighted Average Remaining Contractual Term (in years) \| Years	9.18	9.18	9.25
Outstanding at end of year, Weighted Average Remaining Contractual Term \| Years	7.20	7.81	8.38
Vested/Exercisable at end of period, Weighted Average Remaining Contractual Term \| Years	6.59	7.14	7.54
Outstanding at beginning of year, Aggregate Intrinsic Value \| $	$ (9,080,625)
Granted, Aggregate Intrinsic Value	$ (1,441,746)
Outstanding at end of year, Aggregate Intrinsic Value \| $	$ (18,015,060)	$ (9,080,625)
Vested/Exercisable at end of year, Aggregate Intrinsic Value \| $	$ 16,912,225

Share Based Compensation, 401(k) Plan and Deferred Compensation (Weighted-Average Assumptions) (Details) - Years	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Risk-free interest rate	2.86%	3.03%
Dividend yield	5.01%	6.53%
Volatility factor	48.02%	46.89%
Weighted-average expected life	7	7

Share Based Compensation, 401(k) Plan and Deferred Compensation (Restricted Share Activity) (Details) - Restricted Share Awards [Member]	12 Months Ended
	Dec. 31, 2011 $ / shares shares
Company's restricted share activity
Non-vested at January 1, 2011, shares \| shares	851,278
Non-vested at January 1, 2011, Weighted Average Grant Date Fair value \| $ / shares	$ 10.75
Granted, shares \| shares	197,035
Granted, Weighted Average Grant Date Fair value \| $ / shares	$ 11.92
Vested, shares \| shares	(237,541)
Vested, Weighted Average Grant Date Fair value \| $ / shares	$ 19.76
Forfeited, shares \| shares	(3,481)
Forfeited, Weighted Average Grant Date Fair Value \| $ / shares	$ 11.47
Non-vested at December 31, 2011, shares \| shares	807,291
Non-vested at December 31, 2011, Weighted Average Grant Date Fair value \| $ / shares	$ 9.46

Share Based Compensation, 401(k) Plan and Deferred Compensation (Details Textuals) $ / shares in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2011 Age	Dec. 31, 2011 USD ($) Years $ / shares shares	Dec. 31, 2010 USD ($) $ / shares shares	Dec. 31, 2009 USD ($) $ / shares shares	May 24, 2011 shares	Mar. 02, 2011 shares	Mar. 04, 2010 shares	Apr. 02, 2009 shares	Apr. 01, 2009 shares	Dec. 31, 2008 shares
Share Based and Deferred Compensation (Textuals) [Abstract]
Options outstanding under equity incentive plan \| shares		3,599,672	3,116,611	2,404,567						1,754,648
Compensation expense recognized		$ 6,400,000	$ 6,100,000	$ 5,300,000
Stock-based compensation expense, capitalized		$ 1,500,000	1,300,000	800,000
Share-based Compensation Arrangement by Share-based Payment Award, Term		10 years
Stock Option [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Unvested options \| shares		1,311,943
Unrecognized compensation expenses		$ 2,400,000
Weighted average period over which options will be recognized \| Years		1.5
Compensation expense recognized		$ 1,400,000	1,000,000	600,000
Stock-based compensation expense, capitalized		$ 400,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		3 years
Voluntary termination of employment terms	after reaching age 57 and accumulating at least 15 years years of service with the Company
Age limit of voluntary termination of employment \| Age	57
Accumulated Service Period For Voluntary Termination	15 years
Restricted Share Awards [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Unrecognized compensation expenses		$ 3,700,000
Weighted average period over which options will be recognized \| Years		1.1
Compensation expense recognized		$ 3,200,000	$ 4,000,000	3,200,000
Restricted shares outstanding \| shares		807,291	851,278
Vesting Period, Minimum		3 Years
Vesting Period, Maximum		7 Years
Stock-based compensation expense, capitalized		$ 700,000	$ 900,000	800,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years	three to seven years from the initial grant date
Share-based Compensation Arrangement by Share-based Payment Award, Cliff Vesting, Minimum		3 years
Voluntary termination of employment terms	after reaching age 57 and accumulating at least 15 years years of service with the Company
Age limit of voluntary termination of employment \| Age	57
Accumulated Service Period For Voluntary Termination	15 years
Restricted Performance Share Units Plan [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Compensation expense recognized		$ 1,700,000	1,000,000	400,000
Stock-based compensation expense, capitalized		$ 500,000
Recognized compensation expense awards nominal amounts capitalized				0
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		3 years
Voluntary termination of employment terms	after reaching age 57 and accumulating at least 15 years years of service with the Company
Age limit of voluntary termination of employment \| Age	57
Accumulated Service Period For Voluntary Termination	15 years
Maximum number of shares to be delivered at the end of the measurement period relative to the total shareholder return		equal a certain percentage (not to exceed 200%) of the participant's base units
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Delivered \| shares								372,101
Maximum percentage of the participant's base units		200.00%
Fair value of awards on the grant date		$ 2,000,000	2,000,000	1,100,000
Outperformance Program [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Compensation expense recognized		$ 100,000	400,000	900,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		5 years
Fair value of awards on the grant date		$ 5,900,000
Employee Share Purchase Plan [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Compensation expense recognized		$ 100,000	$ 200,000	$ 300,000
Aggregate share-based awards awarded to executives \| shares		1,250,000
Share purchases made by employees under ESPP		85% of the average closing price per share for a specified period
Share purchases made by employees under ESPP, Percentage		85.00%
Percentage of plan contribution		20.00%
Amount of participant contribution		$ 50,000
Purchase price of shares purchased under ESPP \| $ / shares		$ 0.4	$ 0.5	$ 0.4
Deferred Compensation Plan [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Number of shares to be issued under deferred compensation plan included in total shares outstanding \| shares		300,000	300,000
Deferred Compensation Arrangement With Individual Increase In Compensation Expense		$ 100,000	$ 1,000,000	$ 1,500,000
Deferred Compensation Arrangement With Individual Decrease In Compensation Expense			$ 1,000,000	$ 1,800,000
Executive Officer [Member] \| Stock Option [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Aggregate share-based awards awarded to executives \| shares					101,437	603,241
Executive Officer [Member] \| Restricted Share Awards [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Aggregate share-based awards awarded to executives \| shares						174,012
Executive Officer [Member] \| Restricted Performance Share Units Plan [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Aggregate share-based awards awarded to executives \| shares						124,293	120,955		488,292

Share Based Compensation, 401(k) Plan and Deferred Compensation (401 (k) Plan) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Maximum annual contribution per employee, percent	100.00%
Employers matching contribution, vesting period	3 years
Employer discretionary contribution amount	$ 0.4	$ 0.3	$ 0.2

Distributions (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Common Share Distributions:
Ordinary income	$ 0.37	$ 0.60	$ 0.60
Capital gain	0.0	0.0	0.0
Non-taxable distributions	0.23	0.0	0.0
Distributions per share	$ 0.60	$ 0.60	$ 0.60
Percentage classified as ordinary income (as a percent)	61.67%	100.00%	100.00%
Percentage classified as capital gain (as a percent)	0.00%	0.00%	0.00%
Percentage classified as non-taxable distribution (as a percent)	38.33%	0.00%	0.00%
Preferred Share Distributions:
Total distributions declared (in dollars)	$ 7,992	$ 7,992	$ 7,992

Tax Credit Transactions (Details) $ in Thousands		1 Months Ended			12 Months Ended
Tax Credit Transactions (Details) $ in Thousands	Oct. 19, 2011 USD ($)	Jun. 30, 2010 USD ($)	Dec. 31, 2009 USD ($)	Nov. 30, 2008 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Aug. 27, 2010 USD ($)	Nov. 17, 2008 sqft
Tax Credit Transactions (Textuals) [Abstract]
Amount received in advance for project cost					$ 2,694	$ 27,396	$ 23,763
Percentage of tax credit recapture					100.00%
Limit on tax credit claims under the Community Renewal Tax Relief					up to 39% of qualified investments in qualified, active low-income businesses or ventures
Percentage of qualified investments					39.00%
Deferred transaction costs					$ 115,362	106,117
Historic Tax Credit Transaction [Member]
Tax Credit Transactions (Textuals) [Abstract]
Area of IRS Philadelphia Campus building (in square foot) \| sqft									862,692
Percentage of building leased to IRS									100.00%
Tax credit conditions					20% recapture per year beginning one year after the completion of the IRS Philadelphia Campus
Percentage of tax credit recapture					20.00%
Contribution allocated in non controlling interest					$ 2,400	2,100
Recognition of cash received as revenue net of allocated expenses on or after September 2011, period					over the five year credit recapture period as defined in the Internal Revenue Code
Recognition of cash received as revenue net of allocated expenses on or after September 2011, period in years					5 years
Deferred transaction costs					$ 2,100	4,300
Rate of return on noncontrolling interest expected					2.00%
Accretion of non-controlling interest liability					$ 1,300	1,100	$ 200
Cash received as revenue					12,000
Allocated expenses within other income (expense)					$ 500
New Markets Tax Credit Transaction [Member]
Tax Credit Transactions (Textuals) [Abstract]
Tax credit conditions					100% recapture for a period of seven years as provided in the Internal Revenue Code
Recognition of cash received as revenue net of allocated expenses on or after September 2011, period in years					7 years
Deferred transaction costs					$ 5,300	5,300
Expected Benefit From a Qualified NMTC Program					7,800
USB [Member] \| Historic Tax Credit Transaction [Member]
Tax Credit Transactions (Textuals) [Abstract]
Agreed contribution in project cost by USB								$ 64,100
Amount received in advance for project cost		$ 27,400	$ 23,800	$ 10,200
Amount received from contribution	$ 2,700
USB contributions presented within deferred income					51,600	61,400
USB [Member] \| New Markets Tax Credit Transaction [Member]
Tax Credit Transactions (Textuals) [Abstract]
USB contributions presented within deferred income					$ 13,300	$ 13,300

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	$ (1,945)
Change during year	(4,499)	$ 7,320	$ 7,395
Ineffectiveness of the hedges	0	0	125
Reclassification adjustment for (gains) losses reclassified to operations	(153)	(28)	184
Ending Balance	(6,079)	(1,945)
Accumulated Other Comprehensive Income (Loss)
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	(1,945)	(9,138)	(17,005)
Change during year	(4,499)	7,320	7,395
Non-controlling interest consolidated - real estate venture partner's share of unrealized (gains)/losses on derivative financial statements	212	(155)	290
Ineffectiveness of the hedges			(125)
Other			491
Reclassification adjustment for (gains) losses reclassified to operations	(153)	(28)	184
Ending Balance	(6,079)	(1,945)	(9,138)
Unrealized Gains (Losses) on Securities
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	(9)	(9)	(9)
Change during year	0	0	0
Non-controlling interest consolidated - real estate venture partner's share of unrealized (gains)/losses on derivative financial statements	0	0	0
Ineffectiveness of the hedges			0
Other			0
Reclassification adjustment for (gains) losses reclassified to operations	0	0	0
Ending Balance	(9)	(9)	(9)
Cash Flow Hedges
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	(1,936)	(9,129)	(16,996)
Change during year	(4,499)	7,320	7,395
Non-controlling interest consolidated - real estate venture partner's share of unrealized (gains)/losses on derivative financial statements	212	(155)	290
Ineffectiveness of the hedges			(125)
Other			491
Reclassification adjustment for (gains) losses reclassified to operations	(153)	(28)	184
Ending Balance	(6,070)	(1,936)	(9,129)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	(2,080)
Change during year	(4,499)	7,320	7,395
Ineffectiveness of the hedges	0	0	125
Reclassification adjustment for (gains) losses reclassified to operations	(153)	(28)	184
Ending Balance	(6,426)	(2,080)
BRANDYWINE OPERATING PARTNERSHIP, L.P. \| Accumulated Other Comprehensive Income (Loss)
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	2,080	(9,428)	(17,005)
Change during year	(4,499)	7,320	7,395
Ineffectiveness of the hedges			(125)
Other			491
Reclassification adjustment for (gains) losses reclassified to operations	(153)	(28)	(184)
Ending Balance	(6,426)	2,080	(9,428)
BRANDYWINE OPERATING PARTNERSHIP, L.P. \| Unrealized Gains (Losses) on Securities
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	9	(9)	(9)
Change during year		0	0
Ineffectiveness of the hedges			0
Other			0
Reclassification adjustment for (gains) losses reclassified to operations	0	0	0
Ending Balance	(9)	9	(9)
BRANDYWINE OPERATING PARTNERSHIP, L.P. \| Cash Flow Hedges
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	2,071	(9,419)	(16,996)
Change during year	(4,499)	7,320	7,395
Ineffectiveness of the hedges			(125)
Other			491
Reclassification adjustment for (gains) losses reclassified to operations	(153)	(28)	(184)
Ending Balance	$ (6,417)	$ 2,071	$ (9,419)

Segment Information (Details)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2011

USD ($)

Sep. 30, 2011

USD ($)

Jun. 30, 2011

USD ($)

^[1]

Mar. 31, 2011

USD ($)

^[2]

Dec. 31, 2010

USD ($)

Sep. 30, 2010

USD ($)

Jun. 30, 2010

USD ($)

^[1]

Mar. 31, 2010

USD ($)

^[2]

Dec. 31, 2011

USD ($)

Reportable_Segments

Dec. 31, 2010

USD ($)

Dec. 31, 2009

USD ($)

Real estate investments, at cost:

Operating properties

$ 4,793,080

$ 4,834,111

$ 4,793,080

$ 4,834,111

$ 4,512,618

Construction-in-progress

25,083

33,322

25,083

33,322

271,962

Land inventory

109,008

110,055

109,008

110,055

97,368

Total revenue

146,609

$ 144,308

$ 144,094

$ 146,794

146,084

$ 140,179

$ 134,191

$ 139,502

581,805

559,956

567,920

Property operating expenses, real estate taxes and third party management expenses

233,811

227,341

227,160

Net operating income

$ 347,994

332,615

340,760

Number of reportable segments | Reportable_Segments

Pennsylvania Suburbs [Member]

Real estate investments, at cost:

Operating properties

1,218,071

1,199,957

$ 1,218,071

1,199,957

1,219,391

Construction-in-progress

Land inventory

Total revenue

158,248

152,380

157,616

Property operating expenses, real estate taxes and third party management expenses

58,440

59,065

56,297

Net operating income

99,808

93,315

101,319

Philadelphia CBD [Member]

Real estate investments, at cost:

Operating properties

953,870

911,354

953,870

911,354

490,602

Construction-in-progress

Land inventory

Total revenue

125,366

92,110

73,534

Property operating expenses, real estate taxes and third party management expenses

48,792

37,896

31,479

Net operating income

76,574

54,214

42,055

Metropolitan, D.C. [Member]

Real estate investments, at cost:

Operating properties

1,255,803

1,359,776

1,255,803

1,359,776

1,372,213

Construction-in-progress

Land inventory

Total revenue

128,456

137,923

140,438

Property operating expenses, real estate taxes and third party management expenses

47,786

48,318

52,899

Net operating income

80,670

89,605

87,539

New Jersey/ Delaware [Member]

Real estate investments, at cost:

Operating properties

545,657

568,413

545,657

568,413

605,181

Construction-in-progress

Land inventory

Total revenue

81,629

87,711

98,344

Property operating expenses, real estate taxes and third party management expenses

40,500

44,137

45,421

Net operating income

41,129

43,574

52,923

Richmond, Virginia [Member]

Real estate investments, at cost:

Operating properties

307,698

294,406

307,698

294,406

301,474

Construction-in-progress

Land inventory

Total revenue

36,789

36,032

36,201

Property operating expenses, real estate taxes and third party management expenses

14,727

14,010

13,871

Net operating income

22,062

22,022

22,330

Austin, Texas [Member]

Real estate investments, at cost:

Operating properties

257,694

254,019

257,694

254,019

268,806

Construction-in-progress

Land inventory

Total revenue

30,895

32,049

31,311

Property operating expenses, real estate taxes and third party management expenses

13,048

13,401

14,351

Net operating income

17,847

18,648

16,960

California [Member]

Real estate investments, at cost:

Operating properties

254,287

246,186

254,287

246,186

254,951

Construction-in-progress

Land inventory

Total revenue

21,670

22,551

29,283

Property operating expenses, real estate taxes and third party management expenses

11,507

11,852

14,735

Net operating income

10,163

10,699

14,548

Corporate [Member]

Real estate investments, at cost:

Operating properties

Construction-in-progress

25,083

33,322

25,083

33,322

271,962

Land inventory

$ 109,008

$ 110,055

109,008

110,055

97,368

Total revenue

(1,248)

(800)

1,193

Property operating expenses, real estate taxes and third party management expenses

(989)

(1,338)

(1,893)

Net operating income

$ (259)

$ 538

$ 3,086

[1]

[2]

Segment Information (Details 1) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

^[1]

Mar. 31, 2011

^[2]

Dec. 31, 2010

Sep. 30, 2010

Jun. 30, 2010

^[1]

Mar. 31, 2010

^[2]

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Reconciliation of consolidated net operating income

Consolidated net operating income

$ 347,994

$ 332,615

$ 340,760

Less:

Interest expense

(131,405)

(132,640)

(135,740)

Deferred financing costs

(4,991)

(3,770)

(5,864)

Depreciation and amortization

(217,680)

(210,592)

(203,572)

Administrative expenses

(24,602)

(23,306)

(20,821)

Recognized Hedge Activity

(916)

Plus:

Interest income

1,813

3,222

2,499

Historic tax credit transaction income

12,026

Equity in income of real estate ventures

3,775

5,305

4,069

Net gain on sales of interests in real estate ventures

2,791

(3)

Net gain on sale of undepreciated real estate

Loss on real estate venture formation

(222)

Gain (loss) on early extinguishment of debt

(2,776)

(2,110)

23,176

Income (loss) from continuing operations

(13,232)

(31,276)

3,588

Income from discontinued operations

8,517

13,670

4,501

Net income (loss)

$ (4,602)

$ 6,611

$ (6,234)

$ (490)

$ (4,991)

$ (6,616)

$ (5,600)

$ (399)

$ (4,715)

$ (17,606)

$ 8,089

[1]

[2]

Operating Leases (Details) $ in Thousands	Dec. 31, 2011 USD ($)
Minimum future rental payments on non-cancelable leases
2012	$ 443,103
2013	424,764
2014	384,539
2015	344,641
2016	295,045
Thereafter	$ 1,090,697

Commitments and Contingencies (Details)	12 Months Ended
Commitments and Contingencies (Details)	Dec. 31, 2011 USD ($) Years sqft	Dec. 31, 2010 USD ($)	Aug. 05, 2010 USD ($)
Commitments and Contingencies (Textuals) [Abstract]
Mortgage lenders with letters-of-credit	$ 1,900,000	$ 13,200,000
Minimum remaining lease period \| Years	18
Maximum remaining lease period \| Years	92
Annual rental payment under ground lease	The annual rental payment under this ground lease is ten dollars through August 2022 which is when the initial term of the ground lease will end. After the initial term, the Company has the option to renew the lease until 2091.
Minimum amount of annual rental payment	$ 3,000,000
Minimum amount of annual rental payments	$ 4,000,000
Aggregate fair market rent future payment as of the date of acquisition			$ 27,400,000
Area of Two Logan Square in Philadelphia \| sqft	708,844
Amount to be paid if the Company takes fee title to Two Logan Square upon foreclosure of related mortgage	$ 2,900,000
Liability related to acquisition of TRC	700,000
Accretion Of Liability Related To Acquisition	2,900,000
Balance portion of acquisition related liability	$ 1,300,000
Agreed holding period (not to sell) for properties acquired as part of the TRC acquisition	15 years
Three Logan Square [Member]
Commitments and Contingencies (Textuals) [Abstract]
Liability related to acquisition of TRC			$ 900,000
Three Logan Square [Member] \| Ground Lease [Member]
Commitments and Contingencies (Textuals) [Abstract]
Annual rental payment during initial term of ground lease	$ 10

Commitments and Contingencies (Ground Rent) (Details) $ in Thousands	Dec. 31, 2011 USD ($)
Minimum future rental payments on non-cancelable leases
2012	$ 443,103
2013	424,764
2014	384,539
2015	344,641
2016	295,045
Thereafter	1,090,697
Ground Rent [Member]
Minimum future rental payments on non-cancelable leases
2012	1,818
2013	1,818
2014	1,818
2015	1,909
2016	1,909
Thereafter	$ 289,440

Summary of Quarterly Results (Unaudited) (Details) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

^[1]

Mar. 31, 2011

^[2]

Dec. 31, 2010

Sep. 30, 2010

Jun. 30, 2010

^[1]

Mar. 31, 2010

^[2]

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Dec. 31, 2008

Dec. 31, 2007

Dec. 31, 2006

Quarterly Financial Information [Line Items]

Total revenue

$ 146,609

$ 144,308

$ 144,094

$ 146,794

$ 146,084

$ 140,179

$ 134,191

$ 139,502

$ 581,805

$ 559,956

$ 567,920

Net income (loss)

(4,602)

6,611

(6,234)

(490)

(4,991)

(6,616)

(5,600)

(399)

(4,715)

(17,606)

8,089

Net income (loss) allocated to Common Shares

$ (4,240)

$ 6,249

$ (6,069)

$ (439)

$ (4,848)

$ (6,437)

$ (5,441)

$ (348)

$ (4,499)

$ (17,074)

$ 8,026

Basic earnings (loss) per Common Share (in dollars per share)

$ (0.05)

$ 0.03

$ (0.06)

$ (0.02)

$ (0.05)

$ (0.06)

$ (0.02)

$ (0.10)

$ (0.19)

$ 0.00

Diluted earnings (loss) per Common Share (in dollars per share)

$ (0.05)

$ 0.03

$ (0.06)

$ (0.02)

$ (0.05)

$ (0.06)

$ (0.02)

$ (0.10)

$ (0.19)

$ 0.00

Additional income related to electricity charges

$ 500

Overstatement of revenue due to under billing

(500)

Understatement of Revenue

$ 300

$ 200

Restatement Adjustment [Member]

Quarterly Financial Information [Line Items]

Depreciation and amortization expense relating to intangibles

$ (4,700)

$ (1,700)

$ 1,400

$ 1,800

$ 1,700

$ 1,500

[1]

[2]

Schedule II - Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts [Member] - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2009

Valuation and Qualifying Accounts Disclosure [Line Items]

Balance at Beginning of Period

$ 15,222

$ 16,363

$ 15,474

Additions

928

763

2,596

Deductions

^[1]

665

1,904

1,707

Balance at End of Period

$ 15,485

$ 15,222

$ 16,363

[1]	Deductions represent amounts that the Company had fully reserved for in prior periods and pursuit of collection of such amounts was ceased during the period.

Schedule III - Real Estate and Accumulated Depreciation (Reconciliation of Real Estate and Accumulated Depreciation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance at beginning of year	$ 4,834,111	$ 4,512,618	$ 4,608,320
Additions:
Acquisitions	31,454	102,475	0
Capital expenditures	133,550	336,281	80,506
Less:
Dispositions	(206,035)	(117,263)	(176,208)
Balance at end of year	4,793,080	4,834,111	4,512,618
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance at beginning of year	776,078	716,957	639,688
Additions:
Depreciation expense — continuing operations	157,691	133,740	141,309
Depreciation expense — discontinued operations	1,185	1,554	6,494
Less:
Dispositions	(69,244)	(76,173)	(70,534)
Balance at end of year	$ 865,710	$ 776,078	$ 716,957

Schedule III - Real Estate and Accumulated Depreciation (Aggregate Costs for Federal Income Tax Purposes and Ownership Percentage) (Details) - USD ($) $ in Billions	Dec. 31, 2011	Nov. 30, 2010
Real Estate and Accumulated Depreciation [Line Items]
Equity Method Investment, Ownership Percentage		25.00%
Real Estate, Federal Income Tax Basis	$ 4.5
3141 Fairview Park Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Equity Method Investment, Ownership Percentage	50.00%