View Filing Data

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2010	Feb. 23, 2011	Jun. 30, 2010
Statement [Line Items]
Entity Registrant Name	BRANDYWINE REALTY TRUST
Entity Central Index Key	0000790816
Document Type	10-K
Document Period End Date	Dec. 31, 2010
Amendment Flag	false
Document Fiscal Year Focus	2010
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			$ 1,394,281,711
Entity Common Stock, Shares Outstanding		134,520,391
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Statement [Line Items]
Entity Registrant Name	BRANDYWINE OPERATING PARTNERSHIP, L.P.
Entity Central Index Key	0001060386

Consolidated Balance Sheets - USD ($) $ in Thousands	12 Months Ended
Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2010	Dec. 31, 2009
Real estate investments:
Rental properties	$ 4,834,111	$ 4,512,618
Accumulated depreciation	(776,078)	(716,956)
Operating real estate investments, net	4,058,033	3,795,662
Construction-in-progress	33,322	271,962
Land inventory	110,055	97,368
Total real estate investments, net	4,201,410	4,164,992
Cash and cash equivalents	16,565	1,567
Accounts receivable, net	16,009	10,934
Accrued rent receivable, net	95,541	87,173
Investment in real estate ventures, at equity	84,372	75,458
Deferred costs, net	106,117	106,097
Intangible assets, net	97,462	105,163
Notes receivable	18,205	59,008
Other assets	54,697	53,358
Total assets	4,690,378	4,663,750
LIABILITIES AND BENEFICIARIES' EQUITY
Mortgage notes payable	711,789	551,720
Borrowing under credit facilities	183,000	92,000
Unsecured term loan	183,000	183,000
Unsecured senior notes, net of discounts	1,352,657	1,627,857
Accounts payable and accrued expenses	72,235	88,599
Distributions payable	22,623	21,799
Deferred income, gains and rent	121,552	103,367
Acquired lease intangibles, net	29,233	37,087
Other liabilities	36,515	36,581
Total liabilities	$ 2,712,604	$ 2,742,010
Commitments and contingencies (Note 22)
Brandywine Realty Trust's equity:
Common Shares of Brandywine Realty Trust's beneficial interest, $0.01 par value; shares authorized 200,000,000; 134,601,796 and 128,849,176 issued in 2010 and 2009, respectively and 134,485,117 and 128,597,412 outstanding in 2010 and 2009, respectively	$ 1,343	$ 1,286
Additional paid-in capital	2,671,217	2,610,421
Deferred compensation payable in common stock	5,774	5,549
Common shares in treasury, at cost, 116,679 and 251,764 in 2010 and 2009, respectively	(3,074)	(7,205)
Common shares in grantor trust, 291,281 in 2010 and 255,700 in 2009	(5,774)	(5,549)
Cumulative earnings	483,439	501,384
Accumulated other comprehensive loss	(1,945)	(9,138)
Cumulative distributions	(1,301,521)	(1,213,359)
Total Brandywine Realty Trust's equity/Operating Partnership's equity	1,849,502	1,883,432
Non-controlling interests	128,272	38,308
Total equity	1,977,774	1,921,740
Total liabilities and equity	4,690,378	4,663,750
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Real estate investments:
Rental properties	4,834,111	4,512,618
Accumulated depreciation	(776,078)	(716,956)
Operating real estate investments, net	4,058,033	3,795,662
Construction-in-progress	33,322	271,962
Land inventory	110,055	97,368
Total real estate investments, net	4,201,410	4,164,992
Cash and cash equivalents	16,565	1,567
Accounts receivable, net	16,009	10,934
Accrued rent receivable, net	95,541	87,173
Investment in real estate ventures, at equity	84,372	75,458
Deferred costs, net	106,117	106,097
Intangible assets, net	97,462	105,163
Notes receivable	18,205	59,008
Other assets	54,697	53,358
Total assets	4,690,378	4,663,750
LIABILITIES AND BENEFICIARIES' EQUITY
Mortgage notes payable	711,789	551,720
Borrowing under credit facilities	183,000	92,000
Unsecured term loan	183,000	183,000
Unsecured senior notes, net of discounts	1,352,657	1,627,857
Accounts payable and accrued expenses	72,235	88,599
Distributions payable	22,623	21,799
Deferred income, gains and rent	121,552	103,367
Acquired lease intangibles, net	29,233	37,087
Other liabilities	36,515	36,581
Total liabilities	$ 2,712,604	$ 2,742,010
Commitments and contingencies (Note 22)
Redeemable limited partnership units at redemption value; 9,902,752 and 2,809,108 issued and outstanding in 2010 and 2009, respectively	$ 132,855	$ 44,620
Brandywine Realty Trust's equity:
General Partnership Capital, 134,601,796 and 128,849,176 units issued in 2010 and 2009, respectively and 134,485,117 and 128,597,412 units outstanding in 2010 and 2009, respectively	1,743,549	1,783,033
Accumulated other comprehensive loss	(2,080)	(9,428)
Total Brandywine Realty Trust's equity/Operating Partnership's equity	1,844,919	1,877,055
Non-controlling interests	0	65
Total equity	1,844,919	1,877,120
Total liabilities and equity	4,690,378	4,663,750
7.50% Series D Preferred Shares
Brandywine Realty Trust's equity:
Preferred Stock, Value	47,912	47,912
7.50% Series C Preferred Shares
Brandywine Realty Trust's equity:
Preferred Stock, Value	20	20
Total equity	20	20
7.375% Series D Preferred Shares
Brandywine Realty Trust's equity:
Preferred Stock, Value	23	23
Total equity	23	23
7.375% Series E Preferred Shares
Brandywine Realty Trust's equity:
Preferred Stock, Value	$ 55,538	$ 55,538

Consolidated Balance Sheets (Parenthetical)	Dec. 31, 2010 USD ($) shares	Dec. 31, 2009 USD ($) shares
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	134,601,796	128,849,176
Common Shares of Brandywine Realty Trust's beneficial interest, shares outstanding	134,485,117	128,597,412
Common shares in treasury, at cost, shares	116,679	251,764
Common shares in grantor trust, shares	291,281	255,700
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Brandywine Realty Trust's equity:
General Partners' Capital Account, Units Issued	134,601,796	128,849,176
General Partners' Capital Account, Units Outstanding	134,485,117	128,597,412
Redeemable limited partnership, units issued \| $	9,902,752	2,809,108
Redeemable limited partnership, units outstanding \| $	9,902,752	2,809,108
7.50% Series D Preferred Shares \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Brandywine Realty Trust's equity:
Preferred shares, shares issued	2,000,000	2,000,000
Preferred shares, shares outstanding	2,000,000	2,000,000
7.50% Series C Preferred Shares
Brandywine Realty Trust's equity:
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, 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
7.375% Series E Preferred Shares \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Brandywine Realty Trust's equity:
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, 2010	Dec. 31, 2009	Dec. 31, 2008
Revenue:
Rents	$ 466,199	$ 472,770	$ 476,249
Tenant reimbursements	78,774	78,197	76,617
Termination fees	5,766	3,601	4,800
Third party management fees, labor reimbursement and leasing	11,830	17,151	20,401
Other	4,328	3,339	2,865
Total revenue	566,897	575,058	580,932
Operating Expenses:
Property operating expenses	170,151	165,171	158,073
Real estate taxes	54,444	57,093	57,561
Third party management expenses	5,866	7,996	8,965
Depreciation and amortization	212,775	205,863	199,447
General and administrative expenses	23,306	20,821	23,002
Provision for impairment on land inventory			10,841
Total operating expenses	466,542	456,944	457,889
Operating income	100,355	118,114	123,043
Other Income (Expense):
Interest income	3,222	2,499	1,839
Interest expense	(132,640)	(135,740)	(146,646)
Interest expense - amortization of deferred financing costs	(3,770)	(5,864)	(5,450)
Recognized hedge activity		(916)
Equity in income of real estate ventures	5,305	4,069	8,447
(Loss) gain on early extinguishment of debt	(2,110)	23,176	18,105
Income (loss) from continuing operations	(29,638)	5,339	(662)
Discontinued operations:
Income from discontinued operations	1,021	5,212	17,564
Net (loss) gain on disposition of discontinued operations	11,011	1,238	28,473
Provision for impairment		(3,700)	(6,850)
Total discontinued operations	12,032	2,750	39,187
Net income (loss)	(17,606)	8,089	38,525
Net (income) loss from discontinued operations attributable to non-controlling interests - LP units	(255)	(45)	(1,478)
Net income attributable to non-controlling interests - partners' share of consolidated real estate ventures		(30)	(127)
Net (income) loss attributable to non-controlling interests - LP units	787	12	297
Net (income) loss attributable to non-controlling interests	532	(63)	(1,308)
Distribution to Preferred Shares	(7,992)	(7,992)	(7,992)
Amount allocated to unvested restricted shareholders	(512)	(279)	(763)
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	$ (25,578)	$ (245)	$ 28,462
Basic earnings per Common Share:
Continuing operations	$ (0.28)	$ (0.02)	$ (0.11)
Discontinued operations	0.09	0.02	0.43
Basic earnings per Common Share	(0.19)		0.32
Diluted earnings per Common Share:
Continuing operations	(0.28)	(0.02)	(0.11)
Discontinued operations	0.09	$ 0.02	0.43
Diluted earnings per Common Share	$ (0.19)		$ 0.32
Basic weighted average shares outstanding	131,743,275	111,898,045	87,574,423
Diluted weighted average shares outstanding	131,743,275	113,251,291	87,583,163
Net income (loss) attributable to Company
Income (loss) from continuing operations	$ (28,851)	$ 5,321	$ (492)
Income (loss) from discontinued operations	11,777	2,705	37,709
Net income (loss)	(17,074)	8,026	37,217
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue:
Rents	466,199	472,770	476,249
Tenant reimbursements	78,774	78,197	76,617
Termination fees	5,766	3,601	4,800
Third party management fees, labor reimbursement and leasing	11,830	17,151	20,401
Other	4,328	3,339	2,865
Total revenue	566,897	575,058	580,932
Operating Expenses:
Property operating expenses	170,151	165,171	158,073
Real estate taxes	54,444	57,093	57,561
Third party management expenses	5,866	7,996	8,965
Depreciation and amortization	212,775	205,863	199,447
General and administrative expenses	23,306	20,821	23,002
Provision for impairment on land inventory			10,841
Total operating expenses	466,542	456,944	457,889
Operating income	100,355	118,114	123,043
Other Income (Expense):
Interest income	3,222	2,499	1,839
Interest expense	(132,640)	(135,740)	(146,646)
Interest expense - amortization of deferred financing costs	(3,770)	(5,864)	(5,450)
Recognized hedge activity		(916)
Equity in income of real estate ventures	5,305	4,069	8,447
(Loss) gain on early extinguishment of debt	(2,110)	23,176	18,105
Income (loss) from continuing operations	(29,638)	5,339	(662)
Discontinued operations:
Income from discontinued operations	1,021	5,212	17,564
Net (loss) gain on disposition of discontinued operations	11,011	1,238	28,473
Provision for impairment		(3,700)	(6,850)
Total discontinued operations	12,032	2,750	39,187
Net income (loss)	(17,606)	8,089	38,525
Net (income) loss attributable to non-controlling interests		(30)	(127)
Distribution to Preferred Shares	(7,992)	(7,992)	(7,992)
Amount allocated to unvested restricted shareholders	(512)	(279)	(763)
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	$ (26,110)	$ (212)	$ 29,643
Basic earnings per Common Share:
Continuing operations	$ (0.28)	$ (0.02)	$ (0.11)
Discontinued operations	0.09	0.02	0.43
Basic earnings per Common Share	(0.19)	0	0.32
Diluted earnings per Common Share:
Continuing operations	(0.28)	(0.02)	(0.11)
Discontinued operations	0.09	0.02	0.43
Diluted earnings per Common Share	$ (0.19)	$ 0	$ 0.32
Basic weighted average shares outstanding	137,454,796	114,712,869	90,391,044
Diluted weighted average shares outstanding	137,454,796	116,066,115	90,399,784
Net income (loss) attributable to Company
Income (loss) from continuing operations	$ (29,638)	$ 5,309	$ (789)
Income (loss) from discontinued operations	12,032	2,750	39,187
Net income (loss)	$ (17,606)	$ 8,059	$ 38,398

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Statement [Line Items]
Net income (loss)	$ (17,606)	$ 8,089	$ 38,525
Comprehensive income:
Unrealized gain on derivative financial instruments	7,320	7,395	(15,288)
Ineffectiveness of the hedges		(125)
Reclassification of realized (gains)/losses on derivative financial instruments to operations, net	28	(184)	(80)
Unrealized gain (loss) on available-for-sale securities			248
Total comprehensive income	7,348	7,086	(15,120)
Comprehensive income (loss)	(10,258)	15,175	23,405
Comprehensive (income) loss attributable to non-controlling interest	377	(63)	(1,308)
Comprehensive income (loss) attributable to Brandywine Realty Trust/Operating partnership	(9,881)	15,112	22,097
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Statement [Line Items]
Net income (loss)	(17,606)	8,089	38,525
Comprehensive income:
Unrealized gain on derivative financial instruments	7,320	7,395	(15,288)
Ineffectiveness of the hedges		(125)
Reclassification of realized (gains)/losses on derivative financial instruments to operations, net	28	(184)	(80)
Unrealized gain (loss) on available-for-sale securities			248
Total comprehensive income	7,348	7,086	(15,120)
Comprehensive income (loss)	(10,258)	15,175	23,405
Comprehensive (income) loss attributable to non-controlling interest		(30)	(127)
Comprehensive income (loss) attributable to Brandywine Realty Trust/Operating partnership	$ (10,258)	$ 15,145	$ 23,278

Consolidated Statements of Beneficiaries' Equity - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Statement [Line Items]
Beginning Balance	$ 1,921,740	$ 1,722,498	$ 1,850,209
Net income (loss)	(17,606)	8,089	38,525
Comprehensive income	7,348	7,086	(15,120)
Issuance of Common Shares of Beneficial Interest	71,981	242,323
Equity issuance costs	(1,214)
Issuance of LP Units	77,732
Bonus Share Issuance	369	123
Vesting of Restricted Stock	(227)	(212)	326
Restricted Stock Amortization	3,483	3,286	2,884
Restricted Performance Units Amortization	965	288
Conversion of LP units to Common Shares			(319)
Share Cancellation/Forfeiture			(31)
Share Issuance from/to Deferred Compensation Plan	0	131	710
Share Choice Plan Issuance		(46)	(49)
Stock Option Amortization	1,131	602	336
Outperformance Plan Amortization	380	927	989
Trustee Fees Paid in Shares	99	152	155
Exercise of Options	37
Other - consolidated real estate ventures		34
Other activity		678
Adjustment for Non-Controlling Interests	0
Cumulative Effect of Accounting Change for Variable Interest Entities	1,401
Preferred Share distributions	(7,992)	(7,992)	(7,992)
Distributions declared ($1.76, $0.45 and $0.60 per share in 2010, 2009 and 2008, respectively)	(81,853)	(56,227)	(148,125)
Ending Balance	1,977,774	1,921,740	1,722,498
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Statement [Line Items]
Beginning Balance	1,877,120
Net income (loss)	(17,606)	8,089	38,525
Comprehensive income	7,348	7,086	(15,120)
Ending Balance	1,844,919	1,877,120
Common Stock [Member]
Statement [Line Items]
Beginning Balance	$ 1,286	$ 882	$ 870
Beginning Balance, shares	128,849,176	88,610,053	88,614,322
Issuance of Common Shares of Beneficial Interest	$ 57	$ 403
Issuance of Common Shares of Beneficial Interest, shares	5,742,268	40,250,000
Vesting of Restricted Stock	$ 0	$ 2
Conversion of LP units to Common Shares			$ 10
Share Cancellation/Forfeiture			$ 2
Share Cancellation/Forfeiture, Shares			(4,269)
Share Issuance from/to Deferred Compensation Plan, shares	(2,409)	(3,796)
Share Choice Plan Issuance		$ (1)
Share Choice Plan Issuance, shares		(7,081)
Exercise of Options, shares	12,761
Ending Balance	$ 1,343	$ 1,286	$ 882
Ending Balance, shares	134,601,796	128,849,176	88,610,053
Additional Paid-in Capital [Member]
Statement [Line Items]
Beginning Balance	$ 2,610,421	$ 2,351,428	$ 2,348,153
Issuance of Common Shares of Beneficial Interest	71,924	241,920
Equity issuance costs	(1,214)
Vesting of Restricted Stock	(1,114)	(852)	(912)
Restricted Stock Amortization	3,483	3,286	2,884
Restricted Performance Units Amortization	965	288
Share Cancellation/Forfeiture			(33)
Share Issuance from/to Deferred Compensation Plan		(29)
Share Choice Plan Issuance		(45)	(49)
Stock Option Amortization	1,131	602	336
Outperformance Plan Amortization	380	927	989
Trustee Fees Paid in Shares			60
Exercise of Options	37
Other activity		187
Adjustment for Non-Controlling Interests	(14,796)	12,709
Ending Balance	2,671,217	2,610,421	2,351,428
Deferred Compensation Payable in Common Stock [Member]
Statement [Line Items]
Beginning Balance	$ 5,549	$ 6,274	$ 5,651
Beginning Balance, shares	255,700	215,742	171,650
Bonus Share Issuance	$ 369
Bonus Share Issuance, shares	32,607
Vesting of Restricted Stock	$ 103	$ 56	$ 167
Vesting of Restricted Stock, shares	8,989	8,971	9,895
Share Cancellation/Forfeiture			$ (47)
Share Cancellation/Forfeiture, Shares			(1,524)
Share Issuance from/to Deferred Compensation Plan	$ (282)	$ (816)	$ 468
Share Issuance from/to Deferred Compensation Plan, shares	(9,035)	26,092	33,663
Trustee Fees Paid in Shares	$ 35	$ 35	$ 35
Trustee Fees Paid in Shares, shares	3,020	4,895	2,058
Ending Balance	$ 5,774	$ 5,549	$ 6,274
Ending Balance, shares	291,281	255,700	215,742
Common Stock in Grantor Trust [Member]
Statement [Line Items]
Beginning Balance	$ (5,549)	$ (6,274)	$ (5,651)
Bonus Share Issuance	(369)
Vesting of Restricted Stock	(103)	(56)	(167)
Share Cancellation/Forfeiture			47
Share Issuance from/to Deferred Compensation Plan	282	816	(468)
Trustee Fees Paid in Shares	(35)	(35)	(35)
Ending Balance	(5,774)	(5,549)	(6,274)
Treasury stock [Member]
Statement [Line Items]
Beginning Balance	$ (7,205)	$ (14,121)	$ (53,449)
Beginning Balance, shares	251,764	451,116	1,599,637
Bonus Share Issuance	$ 871	$ 1,228
Bonus Share Issuance, shares	(32,607)	(36,826)
Vesting of Restricted Stock	$ 2,304	$ 2,960	$ 2,582
Vesting of Restricted Stock, shares	(76,598)	(86,172)	(77,191)
Conversion of LP units to Common Shares	$ 732	$ 432	$ 35,052
Conversion of LP units to Common Shares, shares	(17,468)	(7,513)	(1,021,608)
Share Cancellation/Forfeiture, Shares			150
Share Issuance from/to Deferred Compensation Plan		$ 1,830	$ 1,502
Share Issuance from/to Deferred Compensation Plan, shares		(54,854)	(44,286)
Trustee Fees Paid in Shares	$ 224	$ 466	$ 192
Trustee Fees Paid in Shares, shares	(8,412)	(13,987)	(5,586)
Ending Balance	$ (3,074)	$ (7,205)	$ (14,121)
Ending Balance, shares	116,679	251,764	451,116
Cumulative Earnings [Member]
Statement [Line Items]
Beginning Balance	$ 501,384	$ 498,716	$ 472,055
Net income (loss)	(17,074)	8,026	37,216
Bonus Share Issuance	(502)	(1,105)
Vesting of Restricted Stock	(1,417)	(2,322)	(1,344)
Conversion of LP units to Common Shares	(266)	(178)	(8,322)
Share Issuance from/to Deferred Compensation Plan		(1,670)	(792)
Trustee Fees Paid in Shares	(125)	(314)	(97)
Adjustment for Non-Controlling Interests	0	231
Cumulative Effect of Accounting Change for Variable Interest Entities	1,439
Ending Balance	483,439	501,384	498,716
Cumulative Distributions [Member]
Statement [Line Items]
Beginning Balance	(1,213,359)	(1,150,406)	(999,654)
Preferred Share distributions	(7,992)	(7,992)	(7,992)
Distributions declared ($1.76, $0.45 and $0.60 per share in 2010, 2009 and 2008, respectively)	(80,170)	(54,961)	(142,760)
Ending Balance	(1,301,521)	(1,213,359)	(1,150,406)
Accumulated Other Comprehensive Income (Loss) [Member]
Statement [Line Items]
Beginning Balance	(9,138)	(17,005)	(1,885)
Comprehensive income	7,193	7,376	(15,120)
Other activity		491
Ending Balance	(1,945)	(9,138)	(17,005)
Accumulated Other Comprehensive Income (Loss) [Member] \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Statement [Line Items]
Beginning Balance	(9,428)	(17,005)	(1,885)
Comprehensive income	7,348	7,086	(15,120)
Other activity		491
Ending Balance	(2,080)	(9,428)	(17,005)
Non-controlling Interests [Member]
Statement [Line Items]
Beginning Balance	38,309	52,961	84,076
Net income (loss)	(532)	63	1,309
Comprehensive income	155	(290)
Issuance of LP Units	77,732
Conversion of LP units to Common Shares	(466)	(254)	(27,059)
Other - consolidated real estate ventures		34
Adjustment for Non-Controlling Interests	14,796	(12,940)
Cumulative Effect of Accounting Change for Variable Interest Entities	(38)
Distributions declared ($1.76, $0.45 and $0.60 per share in 2010, 2009 and 2008, respectively)	(1,683)	(1,266)	(5,365)
Ending Balance	128,272	38,309	52,961
7.50% Series C Preferred Shares
Statement [Line Items]
Beginning Balance	$ 20	$ 20	$ 20
Beginning Balance, shares	2,000,000	2,000,000	2,000,000
Ending Balance	$ 20	$ 20	$ 20
Ending Balance, shares	2,000,000	2,000,000	2,000,000
7.375% Series D Preferred Shares
Statement [Line Items]
Beginning Balance	$ 23	$ 23	$ 23
Beginning Balance, shares	2,300,000	2,300,000	2,300,000
Ending Balance	$ 23	$ 23	$ 23
Ending Balance, shares	2,300,000	2,300,000	2,300,000

Consolidated Statements of Beneficiaries' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Statement [Line Items]
Distributions declared, per share	$ 1.76	$ 0.45	$ 0.6
Cumulative Distributions [Member]
Statement [Line Items]
Distributions declared, per share	1.76	0.45	0.6
Non-controlling Interests [Member]
Statement [Line Items]
Distributions declared, per share	$ 1.76	$ 0.45	$ 0.6

Consolidated Statements of Partners' Equity - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Statement [Line Items]
Beginning Balance	$ 1,921,740	$ 1,722,498	$ 1,850,209
Net income (loss)	(17,606)	8,089	38,525
Other comprehensive income	7,348	7,086	(15,120)
Bonus share issuance	369	123
Conversion of LP Units to common shares			(319)
Share choice plan		(46)	(49)
Vesting of restricted units	(227)	(212)	326
Restricted stock amortization	3,483	3,286	2,884
Restricted performance units amortization	965	288
Outperformance plan amortization	380	927	989
Option amortization	1,131	602	336
Trustee fees paid in shares	99	152	155
Exercise of options	37
Cumulative effect of accounting change for variable interest entities	1,401
Other		678
Distributions to Preferred Mirror Units	(7,992)	(7,992)	(7,992)
Ending Balance	1,977,774	1,921,740	1,722,498
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Statement [Line Items]
Beginning Balance	1,877,120
Net income (loss)	(17,606)	8,089	38,525
Other comprehensive income	7,348	7,086	(15,120)
Ending Balance	1,844,919	1,877,120
Series D Preferred Mirror Units [Member] \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Statement [Line Items]
Beginning Balance	$ 47,912	$ 47,912	$ 47,912
Beginning Balance, shares	2,000,000	2,000,000	2,000,000
Ending Balance	$ 47,912	$ 47,912	$ 47,912
Ending Balance, shares	2,000,000	2,000,000	2,000,000
Series E Preferred Mirror Units [Member] \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Statement [Line Items]
Beginning Balance	$ 55,538	$ 55,538	$ 55,538
Beginning Balance, shares	2,300,000	2,300,000	2,300,000
Ending Balance	$ 55,538	$ 55,538	$ 55,538
Ending Balance, shares	2,300,000	2,300,000	2,300,000
General Partner Capital [Member] \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Statement [Line Items]
Beginning Balance	$ 1,783,033	$ 1,581,887	$ 1,658,465
Beginning Balance, shares	128,597,412	88,158,937	87,014,685
Net income (loss)	$ (17,606)	$ 8,059	$ 38,398
Deferred compensation obligation	$ 0	$ 131	$ 710
Deferred compensation obligation, shares	(2,409)	51,058	44,286
Issuance of LP Units	$ 71,981	$ 242,323
Issuance of LP Units, shares	5,742,268	40,250,000
Bonus share issuance	$ 369	$ 123
Bonus share issuance, shares	32,607	36,826
Conversion of LP Units to common shares	$ 466	$ 254	$ 26,729
Conversion of LP Units to common shares, shares	17,468	7,513	1,021,608
Share choice plan		$ (46)	$ (49)
Share choice plan, shares		(7,081)
Common partnership units cancellation			$ (33)
Common partnership units cancellation, shares			(4,419)
Vesting of restricted units	$ (227)	$ (213)	$ 326
Vesting of restricted units, shares	76,598	86,172	77,191
Restricted stock amortization	$ 3,483	$ 3,286	$ 2,887
Restricted performance units amortization	965	288
Outperformance plan amortization	380	927	989
Option amortization	1,132	602	336
Trustee fees paid in shares	$ 98	$ 152	$ 155
Trustee fees paid in shares, shares	8,412	13,987	5,586
Exercise of options	$ 37
Exercise of options, shares	12,761
Adjustment of redeemable partnership units to liquidation value at period end	$ (13,839)	$ 8,213	$ 3,726
Cumulative effect of accounting change for variable interest entities	1,439
Distributions to Preferred Mirror Units	(7,992)	(7,992)	(7,992)
Distributions to general partnership unit holder	(80,170)	(54,961)	(142,760)
Ending Balance	$ 1,743,549	$ 1,783,033	$ 1,581,887
Ending Balance, shares	134,485,117	128,597,412	88,158,937
Accumulated Other Comprehensive Income (Loss) [Member]
Statement [Line Items]
Beginning Balance	$ (9,138)	$ (17,005)	$ (1,885)
Other comprehensive income	7,193	7,376	(15,120)
Other		491
Ending Balance	(1,945)	(9,138)	(17,005)
Accumulated Other Comprehensive Income (Loss) [Member] \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Statement [Line Items]
Beginning Balance	(9,428)	(17,005)	(1,885)
Other comprehensive income	7,348	7,086	(15,120)
Other		491
Ending Balance	(2,080)	(9,428)	(17,005)
Non controlling Interest Consolidated Real Estate Ventures [Member] \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Statement [Line Items]
Beginning Balance	65		28
Net income (loss)	0	30	127
Adjustment to non-controlling interest	(27)	35
Cumulative effect of accounting change for variable interest entities	(38)
Distributions to general partnership unit holder			(155)
Ending Balance	0	65
Total partners equity [Member] \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Statement [Line Items]
Beginning Balance	1,877,120	1,668,332	1,760,058
Net income (loss)	(17,606)	8,089	38,525
Other comprehensive income	7,348	7,086	(15,120)
Deferred compensation obligation	0	131	710
Issuance of LP Units	71,981	242,323
Bonus share issuance	369	123
Conversion of LP Units to common shares	466	254	26,729
Share choice plan		(46)	(49)
Common partnership units cancellation			(33)
Vesting of restricted units	(227)	(213)	326
Restricted stock amortization	3,483	3,286	2,887
Restricted performance units amortization	965	288
Outperformance plan amortization	380	927	989
Option amortization	1,132	602	336
Trustee fees paid in shares	98	152	155
Exercise of options	37
Adjustment of redeemable partnership units to liquidation value at period end	(13,839)	8,213	3,726
Adjustment to non-controlling interest	(27)	35
Cumulative effect of accounting change for variable interest entities	1,401
Other		491
Distributions to Preferred Mirror Units	(7,992)	(7,992)	(7,992)
Distributions to general partnership unit holder	(80,170)	(54,961)	(142,915)
Ending Balance	$ 1,844,919	$ 1,877,120	$ 1,668,332

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Cash flows from operating activities:
Net income (loss)	$ (17,606)	$ 8,089	$ 38,525
Adjustments to reconcile net income (loss) to net cash from operating activities:
Depreciation	163,169	160,039	158,234
Amortization:
Deferred financing costs	3,770	5,864	5,450
Amortization of debt discount/(premium), net	831	3,495	6,843
Deferred leasing costs	21,516	18,037	16,561
Acquired above (below) market leases, net	(5,960)	(6,661)	(8,104)
Assumed lease intangibles	30,091	32,387	40,663
Deferred compensation costs	4,814	5,200	4,522
Recognized hedge activity		916
Straight-line rent income	(13,705)	(9,116)	(16,543)
Straight-line ground rent expense	1,647	1,473	1,519
Provision for doubtful accounts	2,479	5,371	6,769
Provision for impairment on land inventory			10,841
Provision for impairment on discontinued operations		3,700	6,850
Real estate venture income in excess of cumulative distributions	(4,648)	(2,512)	(808)
Net loss (gain) on sale of interests in real estate	(11,011)	(1,237)	(28,473)
Loss (gain) on early extinguishment of debt	2,110	(23,176)	(18,105)
Cumulative interest accretion of repayments of unsecured notes	(3,433)	(5,009)	(435)
Contributions from historic tax credit transaction, net of deferred costs	27,396	23,763	7,952
Contributions from new market tax credit transaction, net of deferred costs			8,965
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	(4,173)	3,746	(1,631)
Other assets	(2,782)	2,373	3,683
Accounts payable and accrued expenses	(7,980)	(10,067)	2,491
Deferred income, gains and rents	(6,412)	3,059	(1,164)
Other liabilities	5,014	671	(10,738)
Net cash from operating activities	185,127	220,405	233,867
Cash flows from investing activities:
Acquisition of properties	(50,681)
Sales of properties, net	50,089	101,305	370,087
Proceeds from repayment of mortgage notes receivable	40,000
Capital expenditures	(180,943)	(211,892)	(146,583)
Advances for purchase of tenant assets, net of repayments	(1,715)
Loan provided to an unconsolidated Real Estate Venture partner	(826)
Investment in unconsolidated Real Estate Ventures	(5,180)	(14,980)	(934)
Escrowed cash		31,385	(31,385)
Cash distributions from unconsolidated Real Estate Ventures in excess of cumulative equity income	2,205	13,062	2,311
Decrease in cash due to the deconsolidation of variable interest entities	(1,382)
Leasing costs	(23,503)	(21,429)	(29,450)
Net cash used in investing activities	(171,936)	(102,549)	164,046
Cash flows from financing activities:
Proceeds from Credit Facility borrowings	565,000	983,000	514,000
Repayments of Credit Facility borrowings	(474,000)	(1,044,000)	(491,727)
Proceeds from mortgage notes payable	256,104	149,800
Repayments of mortgage notes payable	(51,966)	(84,102)	(25,155)
Proceeds from unsecured term loan			33,000
Proceeds from unsecured notes		247,030
Repayments of unsecured notes	(276,270)	(514,004)	(260,088)
Net settlement of hedge transactions		(5,044)
Debt financing costs	(595)	(24,620)	(278)
Refund of deferred financing costs related to forward commitment	1,659
Net proceeds from issuance of shares/operating units	70,867	242,332
Exercise of stock/units options	37
Distributions paid to shareholders/unitholders	(87,345)	(68,914)	(162,882)
Distributions to noncontrolling interest	(1,684)	(1,691)	(6,459)
Net cash from (used in) financing activities	1,807	(120,213)	(399,589)
Increase (decrease) in cash and cash equivalents	14,998	(2,357)	(1,676)
Cash and cash equivalents at beginning of period	1,567	3,924	5,600
Cash and cash equivalents at end of period	16,565	1,567	3,924
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the years ended December 31, 2010, 2009 and 2008 of $10,385, $8,893 and $16,746, respectively	135,206	139,636	178,725
Supplemental disclosure of non-cash activity:
Note receivable issued in the Northern California transaction at its present value			37,100
Note receivable issued related to the sale of the two Trenton properties, net of $12.9 million deferred gain		9,600
Settlement of note receivable through foreclosure of a parcel of land	(2,795)
Debt assumed by the purchaser in the Northern California transaction			95,300
Proceeds from mortgage notes payable retained by lender and included in other assets (see Note 7)	396
Change in capital expenditures financed through accounts payable at period end	(5,126)	7,086	9,029
Change in capital expenditures financed through retention payable at period end	(2,066)	5,862	(928)
Change in unfunded tenant allowance		5,986
Change in real estate investments due to the deconsolidation of variable interest entities	(37,126)
Change in mortgage notes payable due to the deconsolidation of variable interest entities	(42,877)
Change in non-controlling interest from issuance of limited partnership units (see Note 3)	77,733
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Cash flows from operating activities:
Net income (loss)	(17,606)	8,089	38,525
Adjustments to reconcile net income (loss) to net cash from operating activities:
Depreciation	163,169	160,039	158,234
Amortization:
Deferred financing costs	3,770	5,864	5,450
Amortization of debt discount/(premium), net	831	3,495	6,843
Deferred leasing costs	21,516	18,037	16,561
Acquired above (below) market leases, net	(5,960)	(6,661)	(8,104)
Assumed lease intangibles	30,091	32,387	40,663
Deferred compensation costs	4,814	5,200	4,522
Recognized hedge activity		916
Straight-line rent income	(13,705)	(9,116)	(16,543)
Straight-line ground rent expense	1,647	1,473	1,519
Provision for doubtful accounts	2,479	5,371	6,769
Provision for impairment on land inventory			10,841
Provision for impairment on discontinued operations		3,700	6,850
Real estate venture income in excess of cumulative distributions	(4,648)	(2,512)	(808)
Net loss (gain) on sale of interests in real estate	(11,011)	(1,237)	(28,473)
Loss (gain) on early extinguishment of debt	2,110	(23,176)	(18,105)
Cumulative interest accretion of repayments of unsecured notes	(3,433)	(5,009)	(435)
Contributions from historic tax credit transaction, net of deferred costs	27,396	23,763	7,952
Contributions from new market tax credit transaction, net of deferred costs			8,965
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	(4,173)	3,746	(1,631)
Other assets	(2,782)	2,373	3,683
Accounts payable and accrued expenses	(7,980)	(10,067)	2,491
Deferred income, gains and rents	(6,412)	3,059	(1,164)
Other liabilities	5,014	671	(10,738)
Net cash from operating activities	185,127	220,405	233,867
Cash flows from investing activities:
Acquisition of properties	(50,681)
Sales of properties, net	50,089	101,305	370,087
Proceeds from repayment of mortgage notes receivable	40,000
Capital expenditures	(180,943)	(211,892)	(146,583)
Advances for purchase of tenant assets, net of repayments	(1,715)
Loan provided to an unconsolidated Real Estate Venture partner	(826)
Investment in unconsolidated Real Estate Ventures	(5,180)	(14,980)	(934)
Escrowed cash		31,385	(31,385)
Cash distributions from unconsolidated Real Estate Ventures in excess of cumulative equity income	2,205	13,062	2,311
Decrease in cash due to the deconsolidation of variable interest entities	(1,382)
Leasing costs	(23,503)	(21,429)	(29,450)
Net cash used in investing activities	(171,936)	(102,549)	164,046
Cash flows from financing activities:
Proceeds from Credit Facility borrowings	565,000	983,000	514,000
Repayments of Credit Facility borrowings	(474,000)	(1,044,000)	(491,727)
Proceeds from mortgage notes payable	256,104	149,800
Repayments of mortgage notes payable	(51,966)	(84,102)	(25,155)
Proceeds from unsecured term loan			33,000
Proceeds from unsecured notes		247,030
Repayments of unsecured notes	(276,270)	(514,004)	(260,088)
Net settlement of hedge transactions		(5,044)
Debt financing costs	(595)	(24,620)	(278)
Refund of deferred financing costs related to forward commitment	1,659
Net proceeds from issuance of shares/operating units	70,867	242,332
Exercise of stock/units options	37
Distributions paid to shareholders/unitholders	(89,029)	(70,605)	(169,341)
Net cash from (used in) financing activities	1,807	(120,213)	(399,589)
Increase (decrease) in cash and cash equivalents	14,998	(2,357)	(1,676)
Cash and cash equivalents at beginning of period	1,567	3,924	5,600
Cash and cash equivalents at end of period	16,565	1,567	3,924
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the years ended December 31, 2010, 2009 and 2008 of $10,385, $8,893 and $16,746, respectively	135,206	139,636	178,725
Supplemental disclosure of non-cash activity:
Note receivable issued in the Northern California transaction at its present value			37,100
Note receivable issued related to the sale of the two Trenton properties, net of $12.9 million deferred gain		9,600
Settlement of note receivable through foreclosure of a parcel of land	(2,795)
Debt assumed by the purchaser in the Northern California transaction			95,300
Proceeds from mortgage notes payable retained by lender and included in other assets (see Note 7)	396
Change in capital expenditures financed through accounts payable at period end	(5,126)	7,086	9,029
Change in capital expenditures financed through retention payable at period end	(2,066)	5,862	$ (928)
Change in unfunded tenant allowance		$ 5,986
Change in real estate investments due to the deconsolidation of variable interest entities	(37,126)
Change in mortgage notes payable due to the deconsolidation of variable interest entities	(42,877)
Change in non-controlling interest from issuance of limited partnership units (see Note 3)	$ 77,733

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Supplemental disclosure:
Capitalized interest	$ 10,385	$ 8,893	$ 16,746
Deferred gain debt		12,900
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Supplemental disclosure:
Capitalized interest	$ 10,385	8,893	$ 16,746
Deferred gain debt		$ 12,900

Organization of The Parent Company and The Operating Partnership	12 Months Ended
	Dec. 31, 2010
Statement [Line Items]
ORGANIZATION AND NATURE OF OPERATIONS	1. 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, 2010, owned a 93.1% 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, 2010, the Company owned 208 office properties, 20 industrial facilities and four mixed-use properties (collectively, the “Properties”) containing an aggregate of approximately 25.6 million net rentable square feet. The Company also has a garage property under redevelopment. Therefore, as of December 31, 2010, the Company owned 233 properties containing an aggregate of 25.6 million net rentable square feet. In addition, as of December 31, 2010, the Company owned economic interests in 17 unconsolidated real estate ventures that contain approximately 6.5 million net rentable square feet (collectively, the “Real Estate Ventures”). As of December 31, 2010, the Company also owned approximately 509 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, 2010, the Company was managing approximately 7.8 million net rentable square feet of office and industrial properties for third parties and 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, 2010, the Operating Partnership owns, directly and indirectly, 100% of each of BRSCO, BTRS, BPI, BBL and BPM. As of December 31, 2010, the Management Companies were managing properties containing an aggregate of approximately 33.4 million net rentable square feet, of which approximately 25.6 million net rentable square feet related to Properties owned by the Company and approximately 7.8 million net rentable square feet related to properties owned by third parties and Real Estate Ventures.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

2. 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. Effective December 31, 2010, the Company is reflecting all deferred income, gains, and rents that will be amortized to revenue as a separate line item in the consolidated balance sheets and all liabilities that are expected to cash settle including security deposits as other liabilities to conform to the current year presentation. The change in the groupings of the liabilities combined deferred rents and income of $50.0 million and $47.4 million, respectively, as of December 31, 2009, to the new line item “Deferred income, gains and rents” in the consolidated balance sheets. The change in the groupings of the liabilities also increased other liabilities in the consolidated balance sheets by $2.6 million as of December 31, 2009.

In addition, the Company changed $5.6 million from leasing costs to capital expenditures in the investing section of the statement of cash flows for the year ended December 31, 2009. This change had no effect on the subtotals within the consolidated statement of cash flows.

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. 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 which the Company controls and the limited partners neither have the ability to dissolve the entity nor 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 and impairments) 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-VIE’s 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 will reconsider 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, if certain events occur that are likely to cause a change in the original determinations. The portion of these entities 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. Pursuant to the Company’s adoption of the accounting standard for business combinations as of January 1, 2009, acquisition related costs are expensed as incurred. Prior to the adoption of the accounting standard, acquisition costs were capitalized when 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).

During 2010, the Company 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. As 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, the Company recorded the related adjustments in the current year.

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 $3.4 million in 2010, $3.9 million in 2009, $5.2 and million in 2008 and interest totaling $10.4 million in 2010, $8.9 million in 2009, and $16.7 million in 2008 were capitalized related to development of certain Properties and land holdings.

Impairment or Disposal of Long-Lived Assets

The accounting standard for property, plant and equipment provides a single accounting model for long-lived assets as held-for-sale, broadens the scope of businesses to be disposed of that qualify for reporting as discontinued operations and changes the timing of recognizing losses on such operations.

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 year ended December 31, 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 the prior year. The Company also recorded an impairment charge on properties designated as held for sale at June 30, 2008 of $6.85 million; these properties were sold during the last quarter of 2008.

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, 2010.

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, 2010 and 2009, 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 $3.7 million and $11.6 million in 2010, respectively and $4.2 million and $12.2 million in 2009, 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 variable interest entities. These investments 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 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.

The Company’s Broadmoor Joint Venture owns an office park in Austin, Texas which is currently leased to a single tenant who is also a partner in the joint venture. The said tenant is also the owner of the land which the joint venture currently leases under an existing ground lease agreement. The office buildings’ lease renewals are currently under negotiation. Given the current circumstances, the Company performed an impairment assessment of its investment in the venture using probability weighted scenarios that include varying outcomes. The Company believes that a market participant would assess the probabilities of these outcomes in the same fashion. In evaluating the scenarios, the Company has determined that the fair value of its investment marginally exceeded its carrying value and the investment is not impaired at December 31, 2010. However, given the lease has not yet been executed and the negotiations of specific terms of the lease are ongoing, the ultimate outcome is uncertain and could cause an impairment of the Company’s investment that could be material.

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, 2010:


	December 31,
	2010		2009

Prepaid Ground Rent	$	7,704	$	7,733
Prepaid Real Estate Taxes		7,648		7,492
Rent inducements, net		6,262		6,680
Cash surrender value of life insurance		8,128		6,498
Restricted cash		4,029		5,632
Marketable securities		2,614		2,798
Prepaid insurance		2,432		2,747
Furniture, fixtures and equipment		1,613		2,664
Deposits on future settlements		2,035		1,108
Others		12,232		10,006

Total	$	54,697	$	53,358

Notes Receivable

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%, 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. The $22.9 million notes receivable is related to the sale of the two Trenton properties in the prior year and is presented net of the $12.9 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. See Note 3 for additional information regarding the sale and the Trenton Note. 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.

As of December 31, 2009, notes receivable included a $2.8 million purchase money mortgage with a 20 year amortization period that bears interest at 8.5%, a $7.5 million purchase money mortgage with a 20 year amortization period that bears interest at 8.5% and a $22.5 million 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.

The Company periodically assesses the collectibility of the notes receivable in accordance with the accounting standard for loan receivables. 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 foreclosed note receivables in the current year, there were no other collectibility issues noted as of December 31, 2010 and 2009.

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 $10.9 million in 2010, $6.4 million in 2009, and $14.0 million in 2008. 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 $2.8 million in 2010, $2.7 million in 2009, and $2.5 million in 2008. 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 $1.5 million in 2010, $1.8 million in 2009, and $0.8 million in 2008.

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.

No tenant represented greater than 10% of the Company’s rental revenue in 2010, 2009 or 2008.

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, 2010 and $4.6 billion as of December 31, 2009.

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 2010, 2009, or 2008.

The Parent Company has elected to treat several 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, 2010 and $4.6 billion as of December 31, 2009.

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 2010, 2009, or 2008.

The Operating Partnership has elected to treat several of its subsidiaries as REITs under Sections 856 through 860 of the Code. Each subsidiary REIT has met 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 Share

Basic earnings per share is calculated by dividing income allocated to common shares by the weighted-average number of shares outstanding during the period. Diluted earnings per share includes the effect of common share 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, 2010 and 2009, the total number of treasury shares outstanding was 116,679 shares and 251,764 shares, respectively.

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, 2010, 6.7 million common shares remained available for future awards under the 1997 Plan (including those shares available solely for options and share appreciation rights). Through December 31, 2010, all options awarded under the 1997 Plan had a one to ten-year term.

The Company incurred stock-based compensation expense of $4.8 million during 2010, of which $1.3 million was capitalized as part of the Company’s review of employee salaries eligible for capitalization. The Company recognized stock-based compensation expense of $4.5 million in 2009, of which $0.8 million had been capitalized and $4.6 million in 2008. 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, 2010:

Fair Value Measurements at Reporting

Date Using:

Quoted Prices in

Active Markets for

Significant Other

Unobservable

December 31,

Identical Assets

Observable Inputs

Inputs

Description

2010

(Level 1)

(Level 2)

(Level 3)

Recurring

Assets:

Available-for-Sale Securities

248

—

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, 2009:


	Fair Value Measurements at Reporting
	Date Using:
			Quoted Prices in
			Active Markets for		Significant Other		Unobservable
	December 31,		Identical Assets		Observable Inputs		Inputs
Description	2009		(Level 1)		(Level 2)		(Level 3)
Recurring
Assets:
Available-for-Sale Securities	$	431	$	431	$	—	$	—

Liabilities:
Interest Rate Swaps	$	7,320	$	—	$	7,320	$	—

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, 2010.

Accounting Pronouncements Adopted During 2010

In January 2010, the FASB issued a new accounting standard for distributions to stockholders with components of stock and cash. The guidance clarifies that in calculating earnings per share, an entity should account for the stock portion of the distribution as a stock issuance and not as a stock dividend. The new standard is effective for fiscal years and interim periods ending after December 15, 2009, and should be applied on a retrospective basis. The Company’s adoption of the new standard did not have a material impact on its consolidated financial position or results of operations, as no distributions were paid with stock.

In January 2010, the FASB issued an amendment to the accounting standard for fair value measurements and disclosures. The amendment clarifies and provides additional disclosure requirements related to recurring and non-recurring fair value measurements. Specifically, the guidance revises two disclosure requirements concerning fair value measurements and clarifies two others. It requires separate presentation of significant transfers into and out of Levels 1 and 2 of the fair value hierarchy and disclosure of the reasons for such transfers. Also, it requires the presentation of purchases, sales, issuances and settlements within Level 3 on a gross basis rather than on a net basis. The amendments clarify that disclosures should be disaggregated by class of asset or liability and that disclosures about inputs and valuation techniques should be provided for both recurring and non-recurring fair value measurements. This amendment is effective for fiscal years and interim periods ending after December 15, 2009. The Company’s adoption of the new standard did not have a material impact on its consolidated financial position or results of operations.

In December 2009, the FASB issued a new accounting standard governing transfer of financial assets. This new standard is a revision to the existing accounting standard for the transfer and servicing of financial assets and amends the guidance on accounting for transfers of financial assets, including securitization transactions, where entities have continued exposure to risks related to transferred financial assets. The new accounting standard also expands the disclosure requirements for such transactions. This amendment is effective for fiscal years beginning after November 15, 2009. The Company’s adoption of the new standard did not have a material impact on its consolidated financial position or results of operations.

In June 2009, the FASB issued an amendment to the accounting and disclosure requirements for the consolidation of VIEs. The elimination of the concept of a qualifying special-purpose entity (QSPE) removes the exception from applying the consolidation guidance within this amendment. This amendment requires an enterprise to perform a qualitative analysis when determining whether or not it must consolidate a VIE. The amendment also requires an enterprise to continuously reassess whether it must consolidate a VIE. Additionally, the amendment requires enhanced disclosures about an enterprise’s involvement with VIEs and any significant change in risk exposure due to that involvement, as well as how its involvement with VIEs impacts the enterprise’s financial statements. Finally, an enterprise will be required to disclose significant judgments and assumptions used to determine whether or not to consolidate a VIE. This amendment was adopted on January 1, 2010 and applied prospectively.

As a result of the adoption of the amendment to the accounting and disclosure requirements for the consolidation of VIEs, the Company has determined that it will no longer consolidate three of the VIEs that it has previously consolidated. In reaching its conclusion, the Company considered the requirements provided by the accounting standard to qualitatively assess if the Company was the primary beneficiary of the VIEs based on whether the Company had (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. The Company’s consideration included an assessment of each of the entities with which it has involvement and review of applicable documents such as, but not limited to applicable partnership agreements, real estate venture agreements, LLC agreements, management and leasing agreements. As of January 1, 2010, the Company held interests in 17 real estate ventures, 15 of which are unconsolidated and two of which the Company continues to consolidate. The Company’s basis in reaching its conclusion for these entities is provided below:

Previously Consolidated:

Four Tower Bridge and Six Tower Bridge Ventures

Each of the Four Tower Bridge and Six Tower Bridge Real Estate Ventures was formed as a limited partnership to own and manage an office property located in Conshohocken, Pennsylvania. The Company entered into these ventures with two other partners during 1997 and 1998, respectively. The other partner in Four Tower Bridge owns a 35% interest in the partnership entity and the other partner in Six Tower Bridge owns a 37% interest in the partnership entities. These Real Estate Ventures were determined to be VIEs and were previously consolidated in the Company’s financial statements in accordance with the amended accounting standard for the consolidation of VIEs. The Real Estate Ventures were determined to be VIEs due to insufficient equity at the latest reconsideration event. However, upon the Company’s adoption of the new accounting standard on January 1, 2010, the Company has determined that it will no longer consolidate these Real Estate Ventures after it was determined that the partners have shared power in the ventures and no related party considerations were identified. All significant decisions are approved by both partners in the venture. Accordingly, based on the Company’s analysis, the Company deconsolidated these two Real Estate Ventures in accordance with the new accounting standard.

Coppell Associates

Coppell Associates is a Real Estate Venture that owns one property in Austin, Texas. The Company entered into this venture with another partner which owns a 50% interest in the partnership. This Real Estate Venture is a VIE and was previously consolidated in the Company’s financial statements in accordance with the amended accounting standard for the consolidation of VIEs. The venture was determined to be a VIE due to insufficient equity at the latest reconsideration event. However, upon the Company’s adoption of the new accounting standard on January 1, 2010, the Company has determined that it will no longer consolidate this Real Estate Venture after it concluded that the partners have shared power in the venture. All significant decisions are approved by both partners in the venture. Accordingly, based upon the Company’s analysis, the Company deconsolidated this Real Estate Venture in accordance with the new accounting standard.

VIEs that Continue to be Consolidated:

Projects Related to the Company’s Tax Credit Transactions

During 2008, the Company closed two transactions with US Bancorp (“USB”) related to the historic rehabilitation of the 30th Street Post Office now known as the Internal Revenue Service (“IRS”) Philadelphia Campus and the Cira South Garage both located in Philadelphia, Pennsylvania. The real estate ventures created to facilitate the tax credit transactions were considered as VIEs because the equity investment at risk is not sufficient to permit the entities to receive the tax credits without the financial support from USB or because the rights to determine the significant decisions are not vested in the equity. The Company has also concluded that it is the primary beneficiary of the IRS Philadelphia Campus and the Cira South Garage 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 said entities and, accordingly, by design has substantially all the risks of the entities. Please refer to Note 18 for a detailed discussion of these transactions as well as the amount of deferred income related to these VIEs that the Company has included in its consolidated balance sheets. There were no other significant amounts included in the Company’s consolidated balance sheet related to these entities as the related amounts were eliminated during consolidation.

Other VIEs:

PJP VII

The Company holds a 25% interest in a Real Estate Venture that it entered into with two other partners. One of the other partners holds a 50% interest in the venture while the other partner holds a 25% interest. This venture is considered a VIE due to the fact that at the last reconsideration event, it entered into a construction loan to fund the building construction of the property and it was determined that there was insufficient equity in the joint venture. In addition, this loan has not been refinanced as of December 31, 2010 and the Company guarantees $0.7 million or 8.75% of the total construction note. It is expected that this entity will remain a VIE until the venture refinances the construction loan into a permanent financing. It was determined that the Company does not have the power to direct the significant economic activities of the Real Estate Venture in accordance with the standard and as a result is not the primary beneficiary of this real estate venture.

Residence Inn Hotel

The Company holds a 50% interest in a Real Estate Venture that owns a Residence Inn Hotel located in Conshohocken, Pennsylvania. This Real Estate Venture has two other partners, one of which holds a 46.4% interest and the other holds a 3.6% interest. The Real Estate Venture was considered as a VIE in accordance with the amended accounting standard for the consolidation of VIEs due to the participating rights of the non-equity holder hotel manager. However, the Company has determined that the partners have shared power in the venture. All significant decisions are approved by all partners in the venture. Accordingly this Real Estate Venture was not consolidated in the financial statements of the Company. Upon the adoption of the new accounting standard, the Company still has the same determination that it does not have the power to control the business of the Real Estate Venture and that it is still appropriate to account for this venture under the equity method of accounting.

G&I VI Interchange Office LLC

The Company holds a 20% interest in a Real Estate Venture that owns a portfolio of 29 office properties located in Montgomery, Bucks, and Lehigh counties in Pennsylvania. The other partner in this venture holds an 80% ownership interest. The Real Estate Venture was considered as a VIE in accordance with the amended accounting standard for the consolidation of VIEs. The venture continues to be determined a VIE due to the disproportionate voting rights. The Company has determined that it is not the primary beneficiary of the venture. Accordingly, this Real Estate Venture was not consolidated in the financial statements of the Company. Upon the adoption of the new accounting standard, the Company still has the same determination that it does not have the power to control the business of the Real Estate Venture and that it is still appropriate to account for this venture under the equity method of accounting.

Seven Tower Bridge

The Company has a 10% direct limited partnership ownership interest and a 20% ownership in a REIT that has 50% ownership in a Real Estate Venture that anticipates developing a suburban office building in Conshohocken, Pennsylvania. There are three other partners in this venture holding ownership interests of 50%, 20%, and 20%, respectively. This venture is considered a VIE as the property is under development and there is insufficient equity to fund the construction. The Company has determined that it is not the primary beneficiary of the venture. Accordingly, this Real Estate Venture was not consolidated in the financial statements of the Company. Upon the adoption of the new accounting standard, the Company still has the same determination that it does not have the power to control the business of the Real Estate Venture and that it is still appropriate to account for this venture under the equity method of accounting.

Other Unconsolidated Real Estate Ventures

In accordance with the Company’s adoption of the accounting standard for the consolidation of VIEs, it was determined that the Company would not consolidate the Real Estate Ventures below based on the evaluation of the substantive participating rights of the partners in each venture under the voting interest model:

•

Two Tower Bridge (Company as co-General Partner with 35% Ownership Interest)

•

Eight Tower Bridge (Company as Limited Partner with 3% Preferred Equity Interest)

•

PJP Real Estate Ventures (Company as Operating Member with 25% to 30% Ownership Interest)

•

Macquarie BDN Office LLC (Company as Operating Member with 20% Ownership Interest)

•

Broadmoor Joint Venture (Company as co-Managing Venturer with 50% Ownership Interest)

•

1000 Chesterbrook (Company as co-General Partner with 50% Ownership Interest)

The “other unconsolidated real estate ventures” described above are not VIEs as the other partners in the ventures have either the substantive participating rights in the entities’ normal business operations or the power to direct the activities is shared amongst the partners. As a result of the Company’s review, it has concluded that it is appropriate to account for these entities as unconsolidated Real Estate Ventures under the equity method of accounting.

Additional Considerations

The supporting real estate venture agreements of the entities listed above provided a straightforward determination of whether the Company has control to direct the business activities of the entities. Where the Company has concluded that control is shared, it is generally because of at least one other partner and the Company must agree on decisions that are considered significant. The Company has also determined that it is not the primary beneficiary in these entities as it does not have the power to direct the activities that most significantly impact the economic performance of these entities. Also, if shared control was determined and the Company was considered to be a related party, the Company is not the party deemed to be the most closely associated with the business. 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, 2010. 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, other than perhaps through its general partner standing.

In accordance with the Company’s adoption of the accounting standard as discussed in detail above, the Company’s consolidated balance sheet as of January 1, 2010 has been reduced by the following amounts as a result of deconsolidating the three VIEs (in thousands):


			Combined Balance Sheets		After Deconsolidation
Balance Sheet:	As Reported		of Deconsolidated VIEs		of VIEs

Assets:
Real estate investments, net	$	4,164,992	$	37,288	$	4,127,704
Cash and cash equivalents		1,567		1,438		129
Receivables, net		98,107		1,627		96,480
Deferred costs, net		106,097		1,662		104,435
Other assets		292,987		2,644		290,343

Total assets	$	4,663,750	$	44,659	$	4,619,091


Liabilities:
Long-term debt	$	2,454,577	$	43,027	$	2,411,550
Accounts payable and accrued expenses		88,599		367		88,232
Other liabilities		198,834		682		198,152

Total liabilities		2,742,010		44,076		2,697,934

Equity:
Company’s equity		1,883,432		583		1,882,849
Noncontrolling interests		38,308		—		38,308

Total Liabilities and Equity	$	4,663,750	$	44,659	$	4,619,091

The difference between the net amount removed from the Company’s consolidated balance sheet and the amount of the Company’s retained interest in the deconsolidated VIEs, amounting to $1.4 million, was recognized as a cumulative effect of accounting change to cumulative earnings in the Company’s consolidated balance sheets.

Real Estate Investments

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

REAL ESTATE INVESTMENTS

3. REAL ESTATE INVESTMENTS

As of December 31, 2010 and 2009, the gross carrying value of the Company’s Properties was as follows:


	December 31,
	2010		2009

Land	$	697,724	$	690,441
Building and improvements		3,693,579		3,393,498
Tenant improvements		442,808		428,679

	$	4,834,111	$	4,512,618

Acquisitions and Dispositions

2010

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 currently 67.2% leased. 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 rank on parity with the Operating Partnership’s Class A units as to distributions but do not begin to accrue distributions and are not entitled to allocations of income or loss prior to August 5, 2011. Thereafter, the Class F (2010) units will be entitled to receive the same distributions that the Parent Company pays on its common shares. 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 Company funded the cash portion of the acquisition price through an advance under its $600.0 million Credit Facility (the “Credit Facility”) and with available corporate funds. The assumed security deposit obligation is included in other liabilities in the Company’s consolidated balance sheets.

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 issued are subject to redemption at the option of the holder after the first anniversary of the acquisition. The Operating Partnership may, at its option, 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.

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:


	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):


			Weighted Average
	August 5,		Amortization Period
	2010		(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	$	(0.28	)	$	(0.02	)

Basic — as pro forma	$	(0.28	)	$	—


Diluted — as reported	$	(0.28	)	$	(0.02	)

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

As of December 31, 2010, two of the Company’s building properties located in King of Prussia, Pennsylvania are currently undergoing demolition and the remaining land balances are presented as land inventory in the Company’s consolidated balance sheets. The Company has determined that there was a change in the estimated useful lives of the buildings resulting from the ongoing demolition causing an acceleration of depreciation expense. During year ended December 31, 2010, the Company recognized the remaining net book value of the two buildings aggregating to $2.7 million as depreciation, with the land amounts of $1.1 million being reclassified to land inventory for potential future development. All related demolition costs are charged to earnings.

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.

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.

2009

The Company did not complete any acquisitions during the year ended December 31, 2009.

On October 13, 2009, the Company sold a condominium unit consisting of 40,508 square feet and an undivided interest in an office building in Lawrenceville, New Jersey, for a sales price of $7.9 million. This condominium unit was occupied at the dale of sale.

On October 1, 2009, the Company sold two office properties, totaling 473,658 net rentable square feet in Trenton, New Jersey for a stated sales price of $85.0 million. The Company provided to the buyer a $22.5 million seven-year, approximately 6.00% cash pay/7.64% accrual second mortgage loan. This sale was recorded using the installment sales method of accounting for real estate sales which requires each cash payment received (including the buyer’s payments under its first mortgage) to be apportioned in the same ratio as total cost and total profit bear to sales value as basis for profit recognition. Accordingly, the Company recognized a gain on sale of $2.7 million upon receipt of cash from the buyer in 2009 and expects to recognize the remaining gain of $12.9 million substantially upon the repayment of the second mortgage in 2016. The buyer has the option to extend the maturity date of the second mortgage for an additional three years subject to certain conditions under the loan agreement. Interest income on the second mortgage is recognized as it is received. In addition, the Company was engaged to manage the properties sold during the term of the second mortgage and is entitled for a management fee equal to 2.5% of all gross receipts from the operation of the properties and will be reimbursed for all management related expenses. These properties were 96.5% occupied at the date of sale.

On April 29, 2009, the Company sold 7735 Old Georgetown Road, a 122,543 net rentable square feet office property located in Bethesda, Maryland, for a sales price of $26.5 million. This property was fully occupied at the date of sale.

On March 16, 2009, the Company sold 305 Harper Drive, a 14,980 net rentable square feet office property located in Moorestown, New Jersey, for a sales price of $1.1 million. This property was vacant at the date of sale.

On February 4, 2009, the Company sold two office properties, totaling 66,664 net rentable square feet in Exton, Pennsylvania, for an aggregate sales price of $9.0 million. These properties were 85.7% occupied at the date of sale.

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

Investment in Unconsolidated Ventures

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

INVESTMENT IN UNCONSOLIDATED VENTURES

4. INVESTMENT IN UNCONSOLIDATED VENTURES

As of December 31, 2010, the Company had an aggregate investment of approximately $84.4 million in its 17 actively operating unconsolidated Real Estate Ventures. The Company formed these ventures with unaffiliated third parties, or acquired them, to develop or manage office properties or to acquire land in anticipation of possible development of office properties. As of December 31, 2010, 15 of the Real Estate Ventures own 50 office buildings that contain an aggregate of approximately 6.5 million net rentable square feet, one Real Estate Venture owns three 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 3% 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 purchase of Prentiss. 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, 2010 and the Company’s share of the Real Estate Ventures’ income (loss) for the year ended December 31, 2010 was as follows (in thousands):


							Company’s Share
							of 2010 Real			Real Estate		Current
	Ownership			Carrying			Estate Venture			Venture		Interest			Debt
	Percentage (a)			Amount			Income (Loss)			Debt at 100%		Rate			Maturity
Broadmoor Austin Associates		50	%	$	65,953		$	1,867		$	80,541		5.79	%	Apr-2023	(b)
Macquarie BDN Christina LLC		20	%		7,709			918			59,000		8.00	%	June-2011	(c)
One Commerce Square (d)		25	%		2,533			33			130,000		5.67	%	Dec-15
Two Commerce Square (d)		25	%		2,533			33			107,612		6.30	%	May-13
Four Tower Bridge (e)		65	%		1,824			519			9,981		6.62	%	Feb-11	(f)
1000 Chesterbrook Blvd.		50	%		1,516			(194	)		24,934		6.88	%	Dec-11
Two Tower Bridge		35	%		1,145			(322	)		15,166			(g)		(g)
Residence Inn Tower Bridge		50	%		873			310			14,480		5.63	%	Feb-16
PJP VII		25	%		383			205			8,295		L+1.55	%	Nov-13
PJP II		30	%		282			109			4,490		6.12	%	Nov-23
PJP V		25	%		244			91			5,949		6.47	%	Aug-19
Seven Tower Bridge		20	%		105			—			10,603			(h)		(h)
PJP VI		25	%		75			72			9,031		6.08	%	Apr-23
Six Tower Bridge (e)		63	%		64			(77	)		13,097		7.79	%	Aug-12
G&I Interchange Office LLC (DRA — N. PA) (i)		20	%		—			935			184,000		5.78	%	Jan-15
Eight Tower Bridge		3.4	%		—			31			52,500		L+5.00	%	Jun-12
Coppell Associates (e)		50	%		(867	)		(159	)		18,708			(j)		(j)
Five Tower Bridge					—			631
Invesco, L.P.					—			303

				$	84,372		$	5,305		$	748,387


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

(b)		The loan allows prepayment in April 2011 without penalty. The loan matures in 2023 and is subject to an interest increase in April 2011. over the five year treasury spread and interest only through maturity. The loan is expected to close in the second quarter of 2011.

(c)		The real estate venture is currently finalizing a new five year loan for an expected amount of $60.0 million with an interest of 4.5% and interest only payments through maturity. The loan is expected to close in the second quarter of 2011.

(d)		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.

(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)		This loan was replaced with a new financing of $11.0 million on February 8, 2011. The new loan features a 5.2% rate and a 10-year term with a 30 year amortization schedule.

(g)		Consists of a $11.9 million fixed rate mortgage with a 5.72% interest rate and May 2013 maturity date; also includes $3.3 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 3% through February 2011, 4% through February 2012, and 5% through February 2013. The total loan amount of $10.6 million as presented above also includes a 3% fixed rate loan (interest only through maturity) with a balance of $0.6 million as of December 31, 2010. 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)		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.

(j)		Comprised of two fixed rate mortgages: a senior fixed rate note of $16,600 at 5.75% that matures in March 2016 and a junior fixed rate note of $2,462 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, 2010 and 2009 (in thousands):


	December 31,
	2010 (a)		2009
Net property	$	804,705	$	503,932
Other assets		105,576		96,643
Other Liabilities		44,509		37,774
Debt		748,387		470,232
Equity		117,385		92,569
Company’s share of equity (Company’s basis)		84,372		75,458


(a) -		Includes the three real estate ventures that were deconsolidated upon the adoption of the new accounting standard for the consolidation of VIEs.

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, 2010, 2009 and 2008 (in thousands):


	Years ended December 31,
	2010 (a)		2009			2008
Revenue	$	118,923	$	105,236		$	105,844
Operating expenses		44,942		38,691			38,036
Interest expense, net		37,505		30,858			30,585
Depreciation and amortization		32,703		36,700			32,057
Net income		3,773		(1,012	)		(416	)
Company’s share of income (Company’s basis)		5,305		4,069			8,447


(a) -		Includes the three real estate ventures that were deconsolidated upon the adoption of the new accounting standard for the consolidation of VIEs.

As of December 31, 2010, the aggregate principal payments of recourse and non-recourse debt payable to third-parties are as follows (in thousands):


2011	$	179,268
2012		71,877
2013		142,160
2014		8,774
2015		301,509
Thereafter		44,799

	$	748,387

As of December 31, 2010, 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.

Deferred Costs

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

DEFERRED COSTS

As of December 31, 2010 and 2009, the Company’s deferred costs were comprised of the following (in thousands):


	December 31, 2010
			Accumulated			Deferred Costs,
	Total Cost		Amortization			net

Leasing Costs	$	123,724	$	(43,930	)	$	79,794
Financing Costs		37,257		(10,934	)		26,323

Total	$	160,981	$	(54,864	)	$	106,117


	December 31, 2009
			Accumulated			Deferred Costs,
	Total Cost		Amortization			net

Leasing Costs	$	124,391	$	(50,643	)	$	73,748
Financing Costs		42,965		(10,616	)		32,349

Total	$	167,356	$	(61,259	)	$	106,097

During 2010, 2009 and 2008, the Company capitalized internal direct leasing costs of $6.2 million, $5.3 million and $7.9 million, respectively, in accordance with the accounting standard for the capitalization of leasing costs.

Intangible Assets and Liabilities

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

INTANGIBLE ASSETS AND LIABILITIES

6. INTANGIBLE ASSETS AND LIABILITIES

As of December 31, 2010 and 2009, the Company’s intangible assets/liabilities were comprised of the following (in thousands):


	December 31, 2010
			Accumulated			Deferred Costs,
	Total Cost		Amortization			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


	December 31, 2009
			Accumulated			Deferred Costs,
	Total Cost		Amortization			net

In-place lease value	$	123,456	$	(71,402	)	$	52,054
Tenant relationship value		97,566		(49,374	)		48,192
Above market leases acquired		15,674		(10,757	)		4,917

Total	$	236,696	$	(131,533	)	$	105,163


Below market leases acquired	$	75,325	$	(38,238	)	$	37,087

For the years ended December 31, 2010, 2009, and 2008, the Company wrote off through the acceleration of amortization approximately $1.5 million, $2.4 million and $1.7 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, 2010, the Company accelerated amortization of a nominal amount of intangible liabilities as a result of tenant move-outs. For the years ended December 31, 2009 and 2008, the Company accelerated amortization of approximately $0.4 million and $0.1 million, respectively, of intangible liabilities as a result of tenant move-outs.

As of December 31, 2010, the Company’s annual amortization for its intangible assets/liabilities is as follows (in thousands, assumes no early terminations):


	Assets		Liabilities
2011	$	30,041	$	7,224
2012		22,155		6,473
2013		13,447		5,930
2014		10,210		4,348
2015		7,249		2,141
Thereafter		14,360		3,117

Total	$	97,462	$	29,233

Debt Obligations

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

DEBT OBLIGATIONS


7. DEBT OBLIGATIONS

The Parent Company guarantees the debt obligations of the Operating Partnership but does not, by itself hold any indebtedness except only for the mortgage debt on the Libertyview property which is included in the table below. All other debt is held directly or indirectly by the Operating Partnership.

The following table sets forth information regarding the Company’s consolidated debt obligations outstanding at December 31, 2010 and 2009 (in thousands):

MORTGAGE DEBT:


							Effective
	December 31,			December 31,			Interest			Maturity
Property / Location	2010			2009			Rate			Date

Plymouth Meeting Exec.	$	—		$	42,042			7.00	%(a),(b)	Dec-10
Four Tower Bridge		—			10,158			6.62	%(c)	Feb-11
Arboretum I, II, III & V		20,386			21,046			7.59	%	Jul-11
Midlantic Drive/Lenox Drive/DCC I		56,514			58,215			8.05	%	Oct-11
Research Office Center		39,145			39,999			5.30	%(a)	Oct-11
Concord Airport Plaza		34,494			35,594			5.55	%(a)	Jan-12
Six Tower Bridge		—			13,557			7.79	%(c)	Aug-12
Newtown Square/Berwyn Park/Libertyview		58,102			59,557			7.25	%	May-13
Coppell Associates II		—			2,711			6.89	%(c)	Dec-13
Southpoint III		2,597			3,255			7.75	%	Apr-14
Tysons Corner		96,507			98,056			5.36	%(a)	Aug-15
Coppell Associates I		—			16,600			5.75	%(c)	Feb-16
Two Logan Square		89,800			89,800			7.57	%	Apr-16
One Logan Square		60,000			60,000			4.50	%(d)	Jul-16
IRS Philadelphia Campus		208,366			—			6.95	%(e)	Sep-30
Cira South Garage		46,335			—			7.11	%(e)	Sep-30

Principal balance outstanding		712,246			550,590
Plus: unamortized fixed-rate debt premiums (discounts), net		(457	)		1,130

Total mortgage indebtedness	$	711,789		$	551,720


UNSECURED DEBT:

$300.0M 5.625% Guaranteed Notes due 2010		—			198,545			5.61	%(f)	Dec-10
Bank Term Loan		183,000			183,000		LIBOR + 0.80		%(g)	Jun-11
Credit Facility		183,000			92,000		LIBOR + 0.725		%(g)	Jun-11
$345.0M 3.875% Guaranteed Exchangeable Notes due 2026		59,835			127,960			5.50	%(h)	Oct-11
$300.0M 5.750% Guaranteed Notes due 2012		175,200			187,825			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		250,000			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
Indenture IA (Preferred Trust I)		27,062			27,062		LIBOR + 1.25		%	Mar-35
Indenture IB (Preferred Trust I)		25,774			25,774		LIBOR + 1.25		%	Apr-35
Indenture II (Preferred Trust II)		25,774			25,774		LIBOR + 1.25		%	Jul-35

Principal balance outstanding		1,722,326			1,910,621
Less: unamortized exchangeable debt discount		(906	)		(4,327	)
unamortized fixed-rate debt discounts, net		(2,763	)		(3,437	)

Total unsecured indebtedness	$	1,718,657		$	1,902,857


Total Debt Obligations	$	2,430,446		$	2,454,577


(a)		These loans were assumed upon acquisition of the related properties. The interest rates presented above reflects the market rate at the time of acquisition.

(b)		On October 1, 2010, the Company prepaid the remaining balance of the loan without penalty. The unamortized fixed-rate debt premium of $0.1 million related to this loan was included as part of loss on early extinguishment debt in the Company’s consolidated statement of operations during the year.

(c)		These loans were removed from the Company’s balance sheet due to the deconsolidation of the related VIEs as discussed in Note 2.

(d)		This mortgage is subject to an interest rate floor of 4.50% on a monthly basis.

(e)		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 related to the IRS Philadelphia Campus and the Cira South Garage (see related discussion below). The financing consists of two separate loans: $209.7 million secured by the IRS Philadelphia Campus and $46.8 million secured by the Cira South Garage.

(f)		On December 15, 2010, the Company paid off the loan at maturity.

(g)		On July 20, 2010, the maturity date of the Bank Term Loan was extended from October 18, 2010 to June 29, 2011. The Bank Term Loan and the Credit Facility may be extended to June 29, 2012 at the Company’s discretion.

(h)		On October 20, 2011, the holders of the Guaranteed Exchangeable Notes have the right to request the redemption of all or a portion of the Guaranteed Exchangeable Notes they hold at a price equal to 100% of the principal amount plus accrued and unpaid interest. Accordingly, the Guaranteed Exchangeable Notes have been presented with an October 20, 2011 maturity date.

During 2010, 2009 and 2008, the Company’s weighted-average effective interest rate on its mortgage notes payable was 6.59%, 6.45% and 6.40%, respectively. As of December 31, 2010 and 2009, the net carrying value of the Company’s Properties that are encumbered by mortgage indebtedness was $989.8 million and $784.2 million, respectively.

During the year ended December 31, 2010, the Company repurchased $82.7 million of its outstanding unsecured Notes in a series of transactions which are summarized in the table below (in thousands):


	Repurchase						Deferred Financing
Notes	Amount		Principal		Loss		Amortization
2010 5.625% Notes	$	2,002	$	1,942	$	37	$	3
2011 3.875% Notes		68,741		68,125		1,762		281
2012 5.750% Notes		13,333		12,625		431		32

	$	84,076	$	82,692	$	2,230	$	316

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 is June 29, 2011 (subject to an extension of one year, at the Company’s option, upon its payment of an extension fee equal to 15 basis points of the committed amount under the Credit Facility). The per annum variable interest rate on the outstanding balances is LIBOR plus 0.725%. The interest rate and facility fee are subject to adjustment upon a change in the Company’s unsecured debt ratings. The Company has the option to increase the Credit Facility to $800.0 million provided that the Company has not committed any defaults under the Credit Facility and is able to acquire additional commitments from its existing lenders or new lenders. As of December 31, 2010, the Company had $183.0 million of borrowings, and $11.2 million in letters of credit outstanding, leaving $405.8 million of unused availability under the Credit Facility. During the years ended December 31, 2010 and 2009, the weighted-average interest rate on Credit Facility borrowings was 1.03% and 2.08%, respectively. As of December 31, 2010 and 2009, the weighted average interest rate on the Credit Facility was 1.02% and 0.96%, 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, 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, 2010, 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, 2010, 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.

The Company accounts 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).

The principal amount outstanding of the 3.875% Guaranteed Exchangeable Notes was $59.8 million at December 31, 2010 and $128.0 million at December 31, 2009, respectively. At certain times and upon certain events, the notes are exchangeable for cash up to their principal amount and, with respect to the remainder, if any, of the exchange value in excess of such principal amount, cash or common shares. The initial exchange rate is 25.4065 shares per $1,000 principal amount of notes (which is equivalent to an initial exchange price of $39.36 per share). 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 unamortized debt discount is $0.9 million at December 31, 2010 and $4.3 million at December 31, 2009, respectively, and will be amortized through October 15, 2011. The effective interest rate at December 31, 2010 and December 31, 2009 was 5.5%. The Company recognized contractual coupon interest of $3.2 million and $8.3 million for the years ended December 31, 2010 and 2009, respectively. In addition, the Company recognized interest on amortization of debt discount of $1.6 million and $4.0 million during the years ended December 31, 2010 and 2009, respectively. Debt discount write-offs resulting from debt repurchases amounted to $2.0 million and $3.8 million for the years ended December 31, 2010 and 2009, respectively.

On September 25, 2009, the Company closed a registered offering of $250.0 million in aggregate principal amount of its 7.50% senior unsecured notes due 2015. The notes were priced at 99.412% of their face amount with a yield to maturity of 7.625%, representing a spread at the time of pricing of 5.162% to the yield on the August 2014 Treasury note. The notes have been reflected net of discount of $1.1 million and $1.4 million in the consolidated balance sheet as of December 31, 2010 and 2009, respectively. The net proceeds which amounted to $247.0 million after deducting underwriting discounts and offering expenses were used to repay the Company’s indebtedness under its unsecured revolving credit facility and for general corporate purposes.

On July 7, 2009, the Company closed a $60.0 million first mortgage on One Logan Square, a 594,361 square foot office property located in Philadelphia, Pennsylvania. This loan accrues interest at a rate of LIBOR plus 3.5% with a minimum LIBOR rate of 1% over a seven-year term with three years of interest only payments and interest and principal payments based on a thirty-year amortization schedule for the remaining four years. The loan proceeds were used for general corporate purposes including repayment of existing indebtedness.

During the year ended December 31, 2008, the Company exercised the accordion feature on its $150.0 million unsecured term loan which it had entered into in October 2007 and borrowed an additional $33.0 million, bringing its total outstanding balance to $183.0 million. All outstanding borrowings under the term loan bear interest at a periodic rate of LIBOR plus 80 basis points. The net proceeds of the term loan were used to reduce indebtedness under the Company’s unsecured revolving credit facility. The Term Loan matures on June 29, 2011 and may be extended at the Company’s option for another year but not beyond the final maturity date of its revolving credit facility. There is no scheduled principal amortization of the Term Loan and the Company may prepay borrowings in whole or in part without premium or penalty. Portions of the Term Loan bear interest at a per annum floating rate equal to: (i) the higher of (x) the prime rate or (y) the federal funds rate plus 0.50% per annum or (ii) a London interbank offered rate that is the rate at which Eurodollar deposits for one, two, three or six months are offered plus between 0.475% and 1.10% per annum (the “Libor Margin”), depending on the Company’s debt rating. The Term Loan Agreement contains financial and operating covenants. Financial covenants include minimum net worth, fixed charge coverage ratio, maximum leverage ratio, restrictions on unsecured and secured debt as a percentage of unencumbered assets and other financial tests. Operating covenants include limitations on the Company’s ability to incur additional indebtedness, grant liens on assets, enter into affiliate transactions, and pay dividends. The Company was in compliance with all covenants as of December 31, 2010.

As of December 31, 2010, the Company’s aggregate scheduled principal payments of debt obligations are as follows (in thousands):


2011	$	554,378
2012		221,136
2013		67,037
2014		255,016
2015		350,157
Thereafter		986,848

Total principal payments		2,434,572
Net unamortized premiums/(discounts)		(4,126	)

Outstanding indebtedness	$	2,430,446

Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

FAIR VALUE OF FINANCIAL INSTRUMENTS

8. 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, 2010 and 2009, 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 of acquiring or assuming 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, 2010 and 2009 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, 2010					December 31, 2009
	Carrying			Fair		Carrying			Fair
	Amount			Value		Amount			Value

Mortgage payable, net of premiums	$	712,246		$	726,348	$	550,590		$	523,745
Unsecured notes payable, net of discounts	$	1,277,716		$	1,338,743	$	1,557,011		$	1,497,356
Variable Rate Debt Instruments	$	444,610		$	432,556	$	353,610		$	341,210
Notes Receivable	$	31,216	(a)	$	28,921	$	71,989	(a)	$	62,776


(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 the prior year accounted for under the accounting standard for installment sales.

Risk Management and Use of Financial Instruments	12 Months Ended
Risk Management and Use of Financial Instruments	Dec. 31, 2010
Statement [Line Items]
RISK MANAGEMENT AND USE OF FINANCIAL INSTRUMENTS	9. 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 current economic conditions have generally resulted in a reduction of the availability of financing and higher borrowing costs. These factors, coupled with a sluggish economy, have reduced the volume of real estate transactions and created credit stresses on most businesses. The Company believes that vacancy rates may increase through 2011 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 and illiquidity 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, 2010. 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. 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, during the current year until the maturity of the remaining interest swaps and as of December 31, 2009, 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 changes in fair values of the hedges during the year ended December 31, 2010 and 2009 were included in other liabilities and accumulated other comprehensive income in the accompanying 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. All of the Company’s existing derivative financial instruments matured on October 18, 2010. 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 2010, 2009 and 2008. 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.

Discontinued Operations

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

DISCONTINUED OPERATIONS

10. DISCONTINUED OPERATIONS

For the years ended December 31, 2010, 2009 and 2008, income from discontinued operations relates to an aggregate of 24 properties containing approximately 3.7 million net rentable square feet that the Company has sold since January 1, 2008.

The following table summarizes revenue and expense information for the properties sold which qualify for discontinued operations reporting since January 1, 2008 (in thousands):


	Years ended December 31,
	2010		2009			2008
Revenue:
Rents	$	4,265	$	13,513		$	59,675
Tenant reimbursements		2,043		6,908			9,302
Termination fees		—		—			25
Other		52		226			279

Total revenue		6,360		20,647			69,281

Expenses:
Property operating expenses		2,401		7,653			23,774
Real estate taxes		936		2,900			7,358
Depreciation and amortization		2,002		4,882			16,008

Total operating expenses		5,339		15,435			47,140

Operating income:		1,021		5,212			22,141
Interest income		—		—			17
Interest expense		—		—			(4,595	)

Income from discontinued operations before gain on sale of interests in real estate		1,021		5,212			17,563

Net gain on disposition of discontinued operations		11,011		1,238			28,474
Provision for impairment		—		(3,700	)		(6,850	)

Income from discontinued operations	$	12,032	$	2,750		$	39,187

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.

Non-Controlling Interests in The Parent Company	12 Months Ended
Non-Controlling Interests in The Parent Company	Dec. 31, 2010
Statement [Line Items]
NON-CONTROLLING INTERESTS IN THE PARENT COMPANY	11. 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, 2010 and 2009, the aggregate book value of the non-controlling interest associated with the redeemable common limited partnership interests in the accompanying consolidated balance sheet was $128.3 million and $38.3 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 $115.4 million and $32.0 million, respectively. Non-controlling Interest — Partners’ Share of Previously Consolidated Real Estate Ventures As discussed in Note 2, as of December 31, 2009, the Company owned interests in three consolidated Real Estate Ventures (Four Tower Bridge, Six Tower Bridge and Coppell Associates) that the Company determined to be VIEs and were consolidated until January 1, 2010. As of December 31, 2009 and prior to their deconsolidation, the aggregate amount related to these non-controlling interests classified within equity was $0.1 million. The Parent Company believes that the aggregate settlement value of these interests was approximately $7.9 million as of December 31, 2009. This amount is based on the estimated liquidation values of the assets and liabilities and the resulting proceeds that the Parent Company would distribute to its real estate venture partners upon dissolution based on book value, as required under the terms of the respective partnership agreements. The partnership agreements of the Real Estate Ventures do not limit the amount that the non-controlling interest partners would be entitled to in the event of liquidation of the assets and liabilities and dissolution of the respective partnerships. As discussed in Note 2, the Parent Company, upon its adoption of the amendment to the accounting and disclosure requirements for the consolidation of VIEs on January 1, 2010, determined that it will no longer consolidate these VIEs.

Non-Controlling Interests in The Operating Partnership	12 Months Ended
Non-Controlling Interests in The Operating Partnership	Dec. 31, 2010
Statement [Line Items]
NON-CONTROLLING INTERESTS IN THE OPERATING PARTNERSHIP	12. NON-CONTROLLING INTERESTS IN THE OPERATING PARTNERSHIP As of December 31, 2009, the Operating Partnership owned interests in three consolidated Real Estate Ventures (see Note 11 above) that own three office properties containing approximately 0.4 million net rentable square feet. These Real Estate Ventures were considered as VIEs under the accounting standard for consolidation. As of December 31, 2009, the aggregate amount related to these non-controlling interests classified within equity was $0.1 million. The Operating Partnership believes that the aggregate settlement value of these interests was approximately $7.9 million as of December 31, 2009. This amount is based on the estimated liquidation values of the assets and liabilities and the resulting proceeds that the Parent Company would distribute to its real estate venture partners upon dissolution, as required under the terms of the respective partnership agreements. The partnership agreements of the Real Estate Ventures do not limit the amount that the non-controlling interest partners would be entitled to in the event of liquidation of the assets and liabilities and dissolution of the respective partnerships. As discussed in Note 2, the Operating Partnership, upon its adoption of the amendment to the accounting and disclosure requirements for the consolidation of VIEs on January 1, 2010, determined that it will no longer consolidate these VIEs.

Beneficiaries Equity of The Parent Company

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

BENEFICIARIES' EQUITY OF THE PARENT COMPANY

13. 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,
	2010						2009						2008
	Basic			Diluted			Basic			Diluted			Basic			Diluted

Numerator
Income (loss) from continuing operations	$	(29,638	)	$	(29,638	)	$	5,339		$	5,339			(662	)		(662	)

Net (loss) income from continuing operations attributable to non-controlling interests		787			787			(18	)		(18	)		170			170
Amount allocable to unvested restricted shareholders		(512	)		(512	)		(279	)		(279	)		(763	)		(763	)
Preferred share dividends		(7,992	)		(7,992	)		(7,992	)		(7,992	)		(7,992	)		(7,992	)

Loss from continuing operations available to common shareholders		(37,355	)		(37,355	)		(2,950	)		(2,950	)		(9,247	)		(9,247	)

Income (loss) from discontinued operations		12,032			12,032			2,750			2,750			39,187			39,187
Discontinued operations attributable to non-controlling interests		(255	)		(255	)		(45	)		(45	)		(1,478	)		(1,478	)

Discontinued operations attributable to common shareholders		11,777			11,777			2,705			2,705			37,709			37,709


Net income available to common shareholders	$	(25,578	)	$	(25,578	)	$	(245	)	$	(245	)	$	28,462		$	28,462


Denominator
Weighted-average shares outstanding		131,743,275			131,743,275			111,898,045			111,898,045			87,574,423			87,574,423
Contingent securities/Stock based compensation		—			—			—			1,353,246			—			8,740

Total weighted-average shares outstanding		131,743,275			131,743,275			111,898,045			113,251,291			87,574,423			87,583,163


Earnings per Common Share:
Income from continuing operations attributable to common shareholders	$	(0.28	)	$	(0.28	)	$	(0.02	)	$	(0.02	)	$	(0.11	)	$	(0.11	)
Discontinued operations attributable to common shareholders		0.09			0.09			0.02			0.02			0.43			0.43

Net income attributable to common shareholders	$	(0.19	)	$	(0.19	)	$	—		$	—		$	0.32		$	0.32

Securities totaling 9,902,752 in 2010, 2,809,108 in 2009, and 2,816,621 in 2008 were excluded from the earnings per share computations because their effect would have been antidilutive. In addition, the Class F (2010) Units, which make up 7,111,112 units out of the total 9,902,752 units as of December 31, 2010, are not entitled to income or loss allocations prior to the first anniversary of the acquisition of Three Logan Square (see Note 3).

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, 2010, 2009 and 2008, earnings representing nonforfeitable dividends as noted in the table above were allocated to the unvested restricted shares.

Common and Preferred Shares

On December 2, 2010, the Parent Company declared a distribution of $0.15 per common share, totaling $20.3 million, which was paid on January 20, 2011 to shareholders of record as of January 6, 2011. On December 2, 2010, the Parent Company declared distributions on its Series C Preferred Shares and Series D Preferred Shares to holders of record as of December 30, 2010. These shares are entitled to a preferential return of 7.50% and 7.375%, respectively. Distributions paid on January 18, 2011 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 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 engaged 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, 2010. Through December 31, 2010, the Parent Company has sold 5,742,268 shares under this program at an average sales price of $12.54 per share resulting in net proceeds of $70.8 million. The Parent Company contributed the net proceeds from the sale of its shares to the Operating Partnership in exchange for the issuance of 5,742,268 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.

On June 2, 2009, the Parent Company completed its public offering (the “offering”) of 40,250,000 of its common shares, par value $0.01 per share. The common shares were issued and sold by the Parent Company to the underwriters at a public offering price of $6.30 per common share in accordance with an underwriting agreement. The common shares sold include 5,250,000 shares issued and sold pursuant to the underwriters’ exercise in full of their over-allotment option under the underwriting agreement. The Parent Company received net proceeds of approximately $242.3 million from the offering net of underwriting discounts, commissions and expenses. The Parent Company used the net proceeds from the offering to reduce its borrowings under its Credit Facility and for general corporate purposes.

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, 2010. As of December 31, 2010, 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, 2010

Statement [Line Items]

PARTNERS' EQUITY OF THE OPERATING PARTNERSHIP

14. 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,
	2010						2009						2008
	Basic			Diluted			Basic			Diluted			Basic			Diluted

Numerator
Income (loss) from continuing operations	$	(29,638	)	$	(29,638	)	$	5,339		$	5,339			(662	)		(662	)

Net (loss) income from continuing operations attributable to non-controlling interests		—			—			(30	)		(30	)		(127	)		(127	)
Amount allocable to unvested restricted unitholders		(512	)		(512	)		(279	)		(279	)		(763	)		(763	)
Preferred share dividends		(7,992	)		(7,992	)		(7,992	)		(7,992	)		(7,992	)		(7,992	)

Loss from continuing operations available to common unitholders		(38,142	)		(38,142	)		(2,962	)		(2,962	)		(9,544	)		(9,544	)

Discontinued operations attributable to common unitholders		12,032			12,032			2,750			2,750			39,187			39,187


Net income available to common unitholders	$	(26,110	)	$	(26,110	)	$	(212	)	$	(212	)		29,643			29,643


Denominator
Weighted-average units outstanding		137,454,796			137,454,796			114,712,869			114,712,869			90,391,044			90,391,044
Contingent securities/Stock based compensation		—			—			—			1,353,246			—			8,740

Total weighted-average units outstanding		137,454,796			137,454,796			114,712,869			116,066,115			90,391,044			90,399,784


Earnings per Common Share:
Income from continuing operations attributable to common unitholders	$	(0.28	)	$	(0.28	)	$	(0.02	)	$	(0.02	)	$	(0.11	)	$	(0.11	)
Discontinued operations attributable to common unitholders		0.09			0.08			0.02			0.02			0.43			0.43

Net income attributable to common unitholders	$	(0.19	)	$	(0.19	)	$	—		$	—		$	0.32		$	0.32

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, 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, 2009, 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 three classes of Common Partnership Units: (i) Class A Limited Partnership Interest which are held by both the Parent Company and outside third parties, (ii) Class F (2010) Limited Partnership Interest which is held by one outside third party and (iii) General Partnership Interests which are held by the Parent Company (collectively, the Class A Limited Partnership Interest, Class F (2010) 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, provided, however, that the Class F (2010) Units do not begin to accrue distributions and are not entitled to allocations of income or loss prior to August 5, 2011.

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, 2010, 2009 and 2008, which was $11.65, $11.40, $7.71, respectively. As of December 31, 2010 and 2009 2,791,640 and 2,809,108 of Class A Units, respectively, were outstanding and owned by outside limited partners of the Operating Partnership.

The Operating Partnership issued the 7,111,112 Class F (2010) Units on August 5, 2010 in connection with its acquisition of Three Logan Square. The Class F (2010) Units were valued based on the closing market price of the Parent Company’s common shares on the acquisition date ($11.54) less $0.60 to reflect that these units do not begin to accrue a dividend prior to the first anniversary of their issuance. The Class F (2010) Units are issued subject to redemption at the option of the holders after the first anniversary of the acquisition. The Operating Partnership may, at its option, satisfy the redemption 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 shares. The redemption value of these Class F (2010) Units and the other redeemable limited partnership units are presented in the mezzanine section of the Operating Partnership’s balance sheet because they can be redeemed in cash or with the Parent Company’s common shares.

On December 2, 2010, the Operating Partnership declared a distribution of $0.15 per Class A common unit, totaling $20.3 million, which was paid on January 20, 2011 to unitholders of record as of January 6, 2011.

On December 2, 2010, 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, 2010. These units are entitled to a preferential return of 7.50% and 7.375%, respectively. Distributions paid on January 18, 2011 to holders of Series D Preferred Mirror Units and Series E Preferred Mirror Units totaled $0.9 million and $1.1 million, respectively.

From the inception of the Offering Program in March 2010 through December 31, 2010, the Parent Company has contributed net proceeds of $70.8 million from the sale of 5,742,268 common shares to the Operating Partnership in exchange for the issuance of 5,742,268 common partnership units to the Parent Company. 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, 2010 and accordingly, during the year ended December 31, 2010, 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, 2010

Statement [Line Items]

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

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

Stock Options

At December 31, 2010, the Company had 3,116,611 options outstanding under its shareholder approved equity incentive plan. There were 1,731,883 options unvested as of December 31, 2010 and $1.6 million of unrecognized compensation expense associated with these options to be recognized over a weighted average period of 1.3 years. During the years ended December 31, 2010, 2009, and 2008, the Company recognized $1.0 million, $0.6 million, and $0.3 million, respectively, of compensation expense included in general and administrative expense related to unvested options. The Company has also capitalized nominal amounts of compensation expense for the said periods as part of the Company’s review of employee salaries eligible for capitalization.

Option activity as of December 31, 2010 and changes during the year ended December 31, 2010 were as follows:


				Weighted		Weighted Average
				Average		Remaining Contractual		Aggregate Intrinsic
	Shares			Exercise Price		Term (in years)		Value
Outstanding at January 1, 2010		2,404,567		$	15.48		8.38	$	(9,816,670	)
Granted		724,805			11.31		9.18		246,434
Exercised		(12,761	)		2.91

Outstanding at December 31, 2010		3,116,611		$	14.56		7.81	$	(9,080,625	)


Vested/Exercisable at December 31, 2010		1,384,728		$	17.63		7.14	$	(8,132,783	)

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, 2010 and 2009:


Grant Date	March 4, 2010			April 1, 2009

Risk-free interest rate		3.03	%		2.20	%
Dividend yield		6.53	%		23.64	%
Volatility factor		46.89	%		40.99	%
Weighted-average expected life	7		yrs	7		yrs


	Years ended December 31,
	2009							2008
						Weighted							Weighted
						Average							Average
				Weighted		Remaining					Weighted		Remaining
				Average		Contractual					Average		Contractual
				Exercise		Term					Exercise		Term
	Shares			Price		(in Years)		Shares			Price		(in Years)

Outstanding at beginning of year		1,754,648		$	20.41		8.77		1,070,099		$	26.13		0.54
Granted		676,491			2.91		9.25		1,824,594			20.61		8.61
Forfeited/Expired		(26,572	)		20.61		—		(1,140,045	)		26.10		—

Outstanding at end of year		2,404,567		$	15.48		8.38		1,754,648		$	20.41		0.54

Vested/Exercisable at end of year		616,119		$	20.03		7.54		1,754,648		$	14.71		1.83

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. Employees vest in employer contributions over a three-year service period. The Company contributions were $0.3 million in 2010, $0.2 million in 2009 and $0.6 million in 2008.

Restricted Share Awards

As of December 31, 2010, 851,278 restricted shares were outstanding and vest over three to seven years from the initial grant date. The remaining compensation expense to be recognized at December 31, 2010 was approximately $4.3 million. That expense is expected to be recognized over a weighted average remaining vesting period of 1.4 years. The Company recognized compensation expense related to outstanding restricted shares of $4.0 million during the year ended December 31, 2010, of which $0.9 million was capitalized as part of the Company’s review of employee salaries eligible for capitalization. For the years ended December 31, 2009 and 2008, the Company recognized $3.2 million (of which $0.8 million was capitalized) and $3.0 million, 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, 2010:


				Weighted
				Average Grant
	Shares			Date Fair value
Non-vested at January 1, 2010		708,580		$	9.69
Granted		240,302			11.56
Vested		(95,796	)		20.46
Forfeited		(1,808	)		19.47

Non-vested at December 31, 2010		851,278		$	10.75

Restricted Performance Share Units Plan

On March 4, 2010 and April 1, 2009, the Compensation Committee of the Parent Company’s Board of Trustees awarded an aggregate of 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, 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, 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.

The fair values of the 2010 and 2009 awards on the grant dates were $2.0 million and $1.1 million, respectively, and are being amortized over the three year cliff vesting period. On the date of each grant, the awards were valued using a Monte Carlo simulation. During the year ended December 31, 2010, the Company recognized total compensation expense for both the 2010 and 2009 awards of $0.6 million and $0.4 million, respectively, related to this plan of which nominal amounts were capitalized as part of the Company’s review of employee salaries eligible for capitalization. During the year ended December 31, 2009, the Company recognized total compensation expense for the 2009 award of $0.3 million related to this plan of which a nominal amount was also 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, 2010, 2009 and 2008, the Company recognized $0.4 million, $0.9 million and $1.0 million, respectively, of compensation expense related to the outperformance program; $0.1 million remains to be recognized as compensation expense as of December 31, 2010.

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 2010 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, 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. During the year ended December 31, 2008, employees made purchases of $0.6 million under the ESPP and the Company recognized $0.1 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 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. For the year ended December 31, 2008, the Company recorded a net reduction in compensation cost of $2.8 million in connection with 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 years ended December 31, 2010 and 2009, the Company recorded a net reduction in compensation cost of $1.0 million and $1.8 million, respectively and net increase in compensation cost of $2.7 million during the year ended December 31, 2008, 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, 2010 and 2009, 0.3 million of such shares 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.

Preferred Shares	12 Months Ended
Preferred Shares	Dec. 31, 2010
Statement [Line Items]
PREFERRED SHARES	16. PREFERRED SHARES 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 14 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 14 for related discussion.

Distributions

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

DISTRIBUTIONS

17. DISTRIBUTIONS


	Years ended December 31,
	2010			2009			2008
Common Share Distributions:
Ordinary income	$	0.60		$	0.60		$	1.53
Capital gain		—			—			0.11
Non-taxable distributions		—			—			0.12

Distributions per share	$	0.60		$	0.60		$	1.76

Percentage classified as ordinary income		100.0	%		100.0	%		86.9	%
Percentage classified as capital gain		0.0	%		0.0	%		6.3	%
Percentage classified as non-taxable distribution		0.0	%		0.0	%		6.8	%

Preferred Share Distributions:
Total distributions declared	$	7,992,000		$	7,992,000		$	7,992,000

Tax Credit Transactions	12 Months Ended
Tax Credit Transactions	Dec. 31, 2010
Statement [Line Items]
TAX CREDIT TRANSACTIONS	18. 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 $64.8 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. The remaining $3.4 million will be advanced upon the Company’s 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 revenue 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 made amounting to $61.4 million as of December 31, 2010 and $34.0 million as of December 31, 2009 are presented within deferred income in the Company’s consolidated balance sheet. The contributions were recorded net of the amount allocated to non-controlling interest as described above of $2.1 million and $1.1 million at December 31, 2010 and December 31, 2009, respectively. The Company anticipates that beginning in September 2011 it will recognize the cash received as revenue net of allocated expenses over the five year tax credit recapture period as defined in the Internal Revenue Code with other income (expense) in its consolidated statements of operations. The Company also 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 costs at December 31, 2010 and 2009 are $4.3 million and $2.4 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 $1.1 million for year-ended December 31, 2010. 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, 2010 and December 31, 2009. 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, 2010 and 2009 is $5.3 million and is included in other assets on the Company’s consolidated balance sheet.

Accumulated Other Comprehensive Income (Loss)

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)

19. 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, 2010 (in thousands):


	Unrealized Gains			Cash Flow			Accumulated Other
*Parent Company*	(Losses) on Securities			Hedges			Comprehensive Loss

Balance at January 1, 2008		(257	)		(1,628	)		(1,885	)
Change during year		—			(15,288	)		(15,288	)
Reclassification adjustments for (gains) losses reclassified into operations		248			(80	)		168

Balance at December 31, 2008		(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	)


	Unrealized Gains			Cash Flow			Accumulated Other
*Operating Partnership*	(Losses) on Securities			Hedges			Comprehensive Loss

Balance at January 1, 2008		(257	)		(1,628	)		(1,885	)
Change during year		—			(15,288	)		(15,288	)
Reclassification adjustments for (gains) losses reclassified into operations		248			(80	)		168

Balance at December 31, 2008		(9	)		(16,996	)		(17,005	)
Change during year		—			7,395			7,395
Ineffectiveness of forward starting swaps		—			(125	)		(125	)
Other								—
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	)

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. During the year ended December 31, 2008, the Company reclassified approximately $(0.5) million to interest expense associated with treasury lock agreements and forward starting swaps previously settled.

Segment Information

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

SEGMENT INFORMATION

20. SEGMENT INFORMATION

As of December 31, 2010, 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.

As a result of the acquisition of Three Logan Square and the placement in service of the IRS Philadelphia Campus and the Cira South Garage, the Company added the Philadelphia CBD segment during the third quarter of the current year. The Philadelphia CBD includes Three Logan Square, the IRS Philadelphia Campus, the Cira South Garage and certain other properties in Philadelphia, PA that were previously included in the Pennsylvania segment. The results of prior periods have been restated to conform to the current year presentation.

Segment information for the three years ended December 31, 2010, 2009 and 2008 are as follows (in thousands):


	Pennsylvania		Philadelphia		Metropolitan,		New Jersey		Richmond,
	Suburbs		CBD		D.C.		/Delaware		Virginia		Austin, Texas		California		Corporate			Total
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		153,166		92,110		137,923		94,240		36,032		32,049		22,552		(1,175	)		566,897
Property operating expenses, real estate taxes and third party management expenses		59,326		37,899		48,321		46,998		14,011		13,402		11,853		(1,349	)		230,461

Net operating income	$	93,840	$	54,211	$	89,602	$	47,242	$	22,021	$	18,647	$	10,699	$	174		$	336,436


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		158,416		73,534		140,438		98,971		36,201		31,311		29,282		6,905			575,058
Property operating expenses, real estate taxes and third party management expenses		56,511		31,479		52,899		45,916		13,871		14,300		14,735		549			230,260

Net operating income	$	101,905	$	42,055	$	87,539	$	53,055	$	22,330	$	17,011	$	14,547	$	6,356		$	344,798


2008:
Real estate investments, at cost:
Operating properties	$	1,232,559	$	486,071	$	1,387,717	$	682,232	$	300,576	$	267,436	$	251,729	$	—		$	4,608,320
Construction-in-progress		—				—		—		—		—		—		122,219			122,219
Land inventory		—				—		—		—		—		—		100,516			100,516

Total revenue		160,107		76,502		138,339		100,027		36,944		33,598		29,590		5,825			580,932
Property operating expenses, real estate taxes and third party management expenses		53,036		32,497		50,876		45,482		13,294		15,630		13,167		617			224,599

Net operating income	$	107,071	$	44,005	$	87,463	$	54,545	$	23,650	$	17,968	$	16,423	$	5,208		$	356,333

Net operating income is defined as total revenue less property operating expenses, real estate taxes and third party management expenses. Segment net operating income includes revenue, real estate taxes and property operating expenses directly related to operation of the properties within the respective geographical region. Segment net operating income 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. Below is a reconciliation of consolidated net operating income to consolidated income (loss) from continuing operations:


	Year Ended December 31,
	2010			2009			2008
	(amounts in thousands)
Consolidated net operating income	$	336,436		$	344,798		$	356,333
Less:
Interest expense		(132,640	)		(135,740	)		(146,646	)
Deferred financing costs		(3,770	)		(5,864	)		(5,450	)
Depreciation and amortization		(212,775	)		(205,863	)		(199,447	)
Administrative expenses		(23,306	)		(20,821	)		(23,002	)
Provision for impairment on land inventory		—			—			(10,841	)
Recognized Hedge Activity		—			(916	)		—
Plus:
Interest income		3,222			2,499			1,839
Equity in income of real estate ventures		5,305			4,069			8,447
Gain (loss) on early extinguishment of debt		(2,110	)		23,177			18,105

Income (loss) from continuing operations		(29,638	)		5,339			(662	)
Income from discontinued operations		12,032			2,750			39,187

Net income (loss)	$	(17,606	)	$	8,089		$	38,525

Operating Leases

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

OPERATING LEASES

21. 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, 2010 are as follows (in thousands):


Year	Minimum Rent
2011	$	552,109
2012		487,290
2013		429,763
2014		372,185
2015		313,411
Thereafter		1,062,209

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

Commitments and Contingencies

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

COMMITMENTS AND CONTINGENCIES

22. 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 $13.2 million and $12.8 million at December 31, 2010 and 2009, 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. Minimum future rental payments on non-cancelable leases at December 31, 2010 are as follows (in thousands):


2011	$	1,818
2012		1,818
2013		1,818
2014		1,909
2015		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 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 706,288 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, 2010, the Company has a balance of $1.2 million for this liability in its consolidated balance sheet.

The Company is currently has been audited by the Internal Revenue Service (the “IRS”) for its 2004 tax year. The audit concerns 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 intends to appeal 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 acquisition of Prentiss Properties Trust (the “Prentiss acquisition”) and the TRC acquisition in 2004, 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, 2010: 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 18), 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.

Subsequent Event	12 Months Ended
Subsequent Event	Dec. 31, 2010
Statement [Line Items]
SUBSEQUENT EVENT	23. SUBSEQUENT EVENT On January 20, 2011, the Company closed on a $9.3 million purchase of a parcel of land in Philadelphia, Pennsylvania. The Company funded the cost of this acquisition with available corporate cash and a draw on its Credit Facility. The Company will contribute the acquired property into a real estate venture in return for a 50% limited interest in the partnership. The real estate venture will be formed to construct a mixed-use development property in the city of Philadelphia.

Summary of Quarterly Results (Unaudited)

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

SUMMARY OF QUARTERLY RESULTS (UNAUDITED)

24. SUMMARY OF QUARTERLY RESULTS (UNAUDITED)

The following is a summary of quarterly financial information as of and for the years ended December 31, 2010 and 2009 (in thousands, except per share data):


	1st			2nd			3rd			4th
	Quarter			Quarter			Quarter			Quarter
2010:
Total revenue	$	141,434		$	135,840		$	141,879		$	147,744
Net loss		(399	)		(5,600	)		(6,616	)		(4,991	)
Net loss allocated to Common Shares		(348	)		(5,441	)		(6,437	)		(4,848	)

Basic earnings per Common Share	$	(0.02	)	$	(0.06	)	$	(0.06	)	$	(0.05	)
Diluted earnings per Common Share	$	(0.02	)	$	(0.06	)	$	(0.06	)	$	(0.05	)

2009:
Total revenue	$	144,958		$	140,388		$	144,824		$	144,888
Net income (loss)		(873	)		5,781			7,309			(4,127	)
Income (loss) allocated to Common Shares		(778	)		5,614			7,148			(3,957	)

Basic earnings per Common Share	$	(0.03	)	$	0.03		$	0.04		$	(0.05	)
Diluted earnings per Common Share	$	(0.03	)	$	0.03		$	0.04		$	(0.05	)


(a)		During the fourth quarter of 2010, the Company recorded an adjustment to depreciation and amortization expense of $1.7 million related to prior years and prior quarters for completed projects that were not closed out of our job cost system in a timely manner resulting in the understatement of depreciation expense in the prior years and prior quarters. The adjustment related to different quarters during the year and resulted in the understatement of net losses of the affected quarters. Understatement of depreciation expense for the first, second, and third quarters of the current year amounted to $0.4 million, $0.3 million, and $0.5 million, respectively. In addition, the Company recorded other adjustments in prior quarters of 2010. In aggregate, all adjustments including the aforementioned adjustments understated or (overstated) the reported net loss by ($0.5) million in the third quarter; and $0.4 million and $0.2 million for the first and second quarters, respectively. See also the disclosure under the caption depreciation and amortization in Note 2. As the Company had concluded that 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, the Company recorded the related adjustments in 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.

Schedule II - Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2010

Statement [Line Items]

Schedule II - Valuation and Qualifying Accounts

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

Schedule II

Valuation and Qualifying Accounts

(in thousands)


	Balance at						Balance
	Beginning						at End
Description	of Period		Additions		Deductions (1)		of Period
Allowance for doubtful accounts:

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

Year ended December 31, 2008	$	10,162	$	6,900	$	1,588	$	15,474


(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, 2010

Statement [Line Items]

Schedule III - Real Estate and Accumulated Depreciation

BRANDYWINE REALTY TRUST AND BRANDYWINE OPERATING PARTNERSHIP, L.P.

Real Estate and Accumulated Depreciation — December 31, 2010

(in thousands)


												Gross Amount at Which Carried
					Initial Cost							December 31, 2010
									Net
									Improvements									Accumulated
									(Retirements)									Depreciation at
			Encumberances at				Building and		Since					Building and				December 31,		Year of		Year		Depreciable
Property Name	City	State	December 31, 2010		Land		Improvements		Acquisition			Land		Improvements		Total (a)		2010 (b)		Construction		Acquired		Life
PENNSYLVANIA SUBURBS

400 Berwyn Park	Berwyn	PA		—		2,657		4,462		14,128			2,657		18,591		21,247		6,019		1999		1999		40
300 Berwyn Park	Berwyn	PA		10,045		2,206		13,422		2,636			2,206		16,059		18,264		5,939		1989		1997		40
1050 Westlakes Drive	Berwyn	PA		—		2,611		10,445		5,046			2,611		15,491		18,102		5,098		1984		1999		40
1200 Swedesford Road	Berwyn	PA		2,597		2,595		11,809		3,369			2,595		15,178		17,773		2,887		1994		2001		40
200 Berwyn Park	Berwyn	PA		7,107		1,533		9,460		2,303			1,533		11,763		13,296		4,789		1987		1997		40
1180 Swedesford Road	Berwyn	PA		—		2,086		8,342		1,276			2,086		9,618		11,704		2,839		1987		2001		40
1160 Swedesford Road	Berwyn	PA		—		1,781		7,124		1,127			1,781		8,251		10,032		2,441		1986		2001		40
100 Berwyn Park	Berwyn	PA		5,469		1,180		7,290		1,378			1,180		8,668		9,848		3,335		1986		1997		40
1100 Cassett Road	Berwyn	PA		—		1,695		6,779		(0	)		1,695		6,779		8,474		1,652		1997		2001		40
980 Harvest Drive	Blue Bell	PA		—		3,304		16,960		(484	)		3,304		16,476		19,780		4,815		1988		2002		40
925 Harvest Drive	Blue Bell	PA		—		1,671		6,606		854			1,671		7,460		9,131		2,746		1990		1998		40
920 Harvest Drive	Blue Bell	PA		—		1,209		6,595		(127	)		1,208		6,470		7,677		2,733		1990		1998		40
426 Lancaster Avenue	Devon	PA		—		1,689		6,756		392			1,689		7,148		8,837		2,675		1990		1998		40
52 Swedesford Square	East Whiteland Twp.	PA		—		4,241		16,579		555			4,241		17,134		21,375		5,922		1988		1998		40
429 Creamery Way	Exton	PA		—		1,368		5,471		399			1,368		5,871		7,238		1,391		1996		2001		40
412 Creamery Way	Exton	PA		—		1,195		4,779		1,135			1,195		5,914		7,109		1,380		1999		2001		40
440 Creamery Way	Exton	PA		—		982		3,927		1,976			982		5,903		6,885		1,852		1991		2001		40
467 Creamery Way	Exton	PA		—		906		3,623		1,365			906		4,988		5,894		1,422		1988		2001		40
436 Creamery Way	Exton	PA		—		994		3,978		675			994		4,653		5,647		1,242		1991		2001		40
442 Creamery Way	Exton	PA		—		894		3,576		684			894		4,260		5,154		1,248		1991		2001		40
100 Arrandale Boulevard	Exton	PA		—		970		3,878		274			970		4,152		5,122		1,129		1997		2001		40
457 Creamery Way	Exton	PA		—		777		3,107		1,020			777		4,127		4,904		855		1990		2001		40
486 Thomas Jones Way	Exton	PA		—		806		3,256		436			806		3,692		4,498		1,511		1990		1996		40
456 Creamery Way	Exton	PA		—		635		2,548		(48	)		635		2,499		3,135		1,073		1987		1996		40
468 Thomas Jones Way	Exton	PA		—		526		2,112		99			527		2,211		2,737		1,015		1990		1996		40
481 John Young Way	Exton	PA		—		496		1,983		14			496		1,997		2,493		487		1997		2001		40
111 Arrandale Road	Exton	PA		—		262		1,048		125			262		1,173		1,435		331		1996		2001		40
500 Enterprise Drive	Horsham	PA		—		1,303		5,188		3,178			1,303		8,366		9,669		2,064		1990		1996		40
One Progress Drive	Horsham	PA		—		1,399		5,629		225			1,399		5,855		7,253		2,498		1986		1996		40
640 Freedom Business Center	King of Prussia	PA		—		4,222		16,891		2,726			4,222		19,617		23,839		7,283		1991		1998		40
555 Croton Road	King of Prussia	PA		—		4,486		17,943		1,124			4,486		19,068		23,553		4,865		1999		2001		40
630 Allendale Road	King of Prussia	PA		—		2,836		4,028		11,784			2,636		16,012		18,648		3,867		2000		2000		40
620 Freedom Business Center	King of Prussia	PA		—		2,770		11,014		3,306			2,770		14,320		17,090		5,701		1986		1998		40
1000 First Avenue	King of Prussia	PA		—		2,772		10,936		3,206			2,772		14,142		16,914		5,157		1980		1998		40
1060 First Avenue	King of Prussia	PA		—		2,712		10,953		2,437			2,712		13,390		16,102		4,592		1987		1998		40
630 Freedom Business Center	King of Prussia	PA		—		2,773		11,144		1,096			2,773		12,240		15,013		4,580		1989		1998		40
1020 First Avenue	King of Prussia	PA		—		2,168		8,576		4,117			2,168		12,693		14,861		4,487		1984		1998		40
1040 First Avenue	King of Prussia	PA		—		2,860		11,282		697			2,860		11,978		14,839		4,224		1985		1998		40
610 Freedom Business Center	King of Prussia	PA		—		2,017		8,070		1,139			2,017		9,210		11,226		3,201		1985		1998		40
650 Park Avenue	King of Prussia	PA		—		1,916		4,378		2,048			1,916		6,425		8,342		2,731		1968		1998		40
500 North Gulph Road	King of Prussia	PA		—		1,303		5,201		1,667			1,303		6,868		8,171		2,705		1979		1996		40
741 First Avenue	King of Prussia	PA		—		1,287		5,151		12			1,287		5,162		6,450		1,875		1966		1998		40
875 First Avenue	King of Prussia	PA		—		618		2,473		3,241			618		5,714		6,332		2,243		1966		1998		40
751-761 Fifth Avenue	King of Prussia	PA		—		1,097		4,391		31			1,097		4,422		5,519		1,599		1967		1998		40
600 Park Avenue	King of Prussia	PA		—		1,012		4,048		385			1,012		4,433		5,445		1,563		1964		1998		40
620 Allendale Road	King of Prussia	PA		—		1,020		3,839		503			1,020		4,342		5,362		1,513		1961		1998		40
640 Allendale Road	King of Prussia	PA		—		439		432		1,480			439		1,912		2,351		504		2000		2000		40
101 Lindenwood Drive	Malvern	PA		—		4,152		16,606		1,644			4,152		18,250		22,402		4,900		1988		2001		40
301 Lindenwood Drive	Malvern	PA		—		2,729		10,915		1,878			2,729		12,793		15,522		3,721		1984		2001		40
300 Lindenwood Drive	Malvern	PA		—		848		3,394		1,334			849		4,727		5,576		1,308		1991		2001		40
1700 Paoli Pike	Malvern	PA		—		458		559		3,344			488		3,873		4,361		1,162		2000		2000		40
100 Lindenwood Drive	Malvern	PA		—		473		1,892		179			473		2,071		2,544		520		1985		2001		40
200 Lindenwood Drive	Malvern	PA		—		324		1,295		110			324		1,405		1,729		322		1984		2001		40
14 Campus Boulevard	Newtown Square	PA		6,588		2,244		4,217		1,514			2,244		5,731		7,975		1,969		1998		1998		40
11 Campus Boulevard	Newtown Square	PA		4,519		1,112		4,067		1,053			1,112		5,119		6,232		1,633		1998		1999		40
17 Campus Boulevard	Newtown Square	PA		4,601		1,108		5,155		(940	)		1,108		4,216		5,323		895		2001		1997		40
15 Campus Boulevard	Newtown Square	PA		4,701		1,164		3,896		229			1,164		4,125		5,289		891		2002		2000		40
18 Campus Boulevard	Newtown Square	PA		3,541		787		3,312		392			787		3,704		4,491		1,657		1990		1996		40
401 Plymouth Road	Plymouth Meeting	PA		—		6,198		16,131		14,225			6,199		30,356		36,554		7,886		2001		2000		40
4000 Chemical Road	Plymouth Meeting	PA		—		4,373		24,546		3,701			4,373		28,247		32,620		2,478		2007		N/A		40
600 West Germantown Pike	Plymouth Meeting	PA		—		3,652		15,288		1,638			3,652		16,926		20,578		3,772		1986		2002		40
630 West Germantown Pike	Plymouth Meeting	PA		—		3,558		14,743		2,123			3,558		16,866		20,424		3,976		1988		2002		40
610 West Germantown Pike	Plymouth Meeting	PA		—		3,651		14,514		2,120			3,651		16,633		20,285		4,341		1987		2002		40
620 West Germantown Pike	Plymouth Meeting	PA		—		3,572		14,435		1,099			3,572		15,534		19,106		3,745		1990		2002		40
2240/2250 Butler Pike	Plymouth Meeting	PA		—		1,104		4,627		1,254			1,104		5,881		6,985		2,668		1984		1996		40
2260 Butler Pike	Plymouth Meeting	PA		—		661		2,727		1,422			662		4,149		4,810		1,868		1984		1996		40
120 West Germantown Pike	Plymouth Meeting	PA		—		685		2,773		410			685		3,183		3,868		1,335		1984		1996		40
140 West Germantown Pike	Plymouth Meeting	PA		—		481		1,976		307			482		2,282		2,764		997		1984		1996		40
351 Plymouth Road	Plymouth Meeting	PA		—		1,043		555		—			1,043		555		1,598		80		N/A		2000		40
150 Radnor Chester Road	Radnor	PA		—		11,925		36,986		11,720			11,897		48,734		60,631		11,913		1983		2004		29
One Radnor Corporate Center	Radnor	PA		—		7,323		28,613		18,499			7,323		47,112		54,435		7,757		1998		2004		29
555 Lancaster Avenue	Radnor	PA		—		8,014		16,508		24,505			8,609		40,417		49,027		12,851		1973		2004		24


												Gross Amount at Which Carried
					Initial Cost							December 31, 2010
									Net
									Improvements									Accumulated
									(Retirements)									Depreciation at
			Encumberances at				Building and		Since					Building and				December 31,		Year of		Year		Depreciable
Property Name	City	State	December 31, 2010		Land		Improvements		Acquisition			Land		Improvements		Total (a)		2010 (b)		Construction		Acquired		Life
201 King of Prussia Road	Radnor	PA		—		8,956		29,811		5,738			8,949		35,556		44,505		10,167		2001		2004		25
Four Radnor Corporate Center	Radnor	PA		—		5,406		21,390		10,095			5,705		31,186		36,891		7,740		1995		2004		30
Five Radnor Corporate Center	Radnor	PA		—		6,506		25,525		2,228			6,578		27,680		34,259		5,640		1998		2004		38
Three Radnor Corporate Center	Radnor	PA		—		4,773		17,961		1,601			4,791		19,544		24,335		4,672		1998		2004		29
Two Radnor Corporate Center	Radnor	PA		—		3,937		15,484		1,143			3,942		16,622		20,564		3,806		1998		2004		29
130 Radnor Chester Road	Radnor	PA		—		2,573		8,338		3,541			2,567		11,885		14,452		2,243		1983		2004		25
170 Radnor Chester Road	Radnor	PA		—		2,514		8,147		3,221			2,509		11,374		13,882		2,666		1983		2004		25
101 West Elm Street	W. Conshohocken	PA		—		6,251		25,209		2,218			6,251		27,426		33,678		4,127		1999		2005		40
1 West Elm Street	W. Conshohocken	PA		—		3,557		14,249		—			3,557		14,866		18,423		1,939		1999		2005		40
595 East Swedesford Road	Wayne	PA		—		2,729		10,917		1,482			2,729		12,398		15,128		2,517		1998		2003		40
575 East Swedesford Road	Wayne	PA		—		2,178		8,712		1,630			2,178		10,342		12,520		2,089		1985		2003		40
565 East Swedesford Road	Wayne	PA		—		1,872		7,489		1,196			1,872		8,685		10,557		1,824		1984		2003		40
585 East Swedesford Road	Wayne	PA		—		1,350		5,401		358			1,350		5,758		7,109		1,113		1998		2003		40
1336 Enterprise Drive	West Goshen	PA		—		731		2,946		47			731		2,993		3,724		1,204		1989		1997		40

PHILADELPHIA CBD

2970 Market Street	Philadelphia	PA		208,366		22,430		226,078		—			22,430		226,078		248,508		2,039		2010		2007		40
2929 Arch Street	Philadelphia	PA		—		—		208,570		18,289			—		226,859		226,859		46,937		2005		N/A		40
130 North 18th Street	Philadelphia	PA		60,000		14,496		107,736		10,115			14,473		117,874		132,347		24,106		1998		2004		23
100 North 18th Street	Philadelphia	PA		89,800		16,066		100,255		5,161			16,066		105,416		121,482		21,743		1988		2004		33
1717 Arch Street	Philadelphia	PA		—		—		98,188		(1	)		—		98,187		98,187		2,056		1990		2010		40
2930 Chestnut Street	Philadelphia	PA		46,335		—		77,968		2			—		77,970		77,970		629		2010		N/A		40
Philadelphia Marine Center	Philadelphia	PA		—		532		2,196		3,249			628		5,349		5,977		1,503	Various			1998		40

METROPOLITAN WASHINGTON, D.C.

11720 Beltsville Drive	Beltsville	MD		—		3,831		16,661		3,873			3,904		20,462		24,365		3,585		1987		2006		46
11700 Beltsville Drive	Beltsville	MD		—		2,808		12,081		349			2,863		12,375		15,239		1,695		1981		2006		46
11710 Beltsville Drive	Beltsville	MD		—		2,278		11,100		(1,127	)		2,321		9,930		12,251		1,290		1987		2006		46
7101 Wisconsin Avenue	Bethesda	MD		—		9,634		48,402		4,639			9,816		52,859		62,675		7,833		1975		2006		45
6600 Rockledge Drive	Bethesda	MD		—		—		37,421		8,736			—		46,157		46,157		6,499		1981		2006		50
11740 Beltsville Drive	Bethesda	MD		—		198		870		42			202		908		1,110		125		1987		2006		46
12015 Lee Jackson Memorial Highway	Fairfax	VA		—		3,770		22,895		1,872			3,842		24,696		28,538		3,179		1985		2006		42
11781 Lee Jackson Memorial Highway	Fairfax	VA		—		3,246		19,836		(494	)		3,307		19,281		22,588		2,894		1982		2006		40
4401 Fair Lakes Court	Fairfax	VA		—		1,569		11,982		305			1,599		12,257		13,856		1,508		1988		2006		52
3130 Fairview Park Drive	Falls Church	VA		—		6,576		51,605		4,317			6,700		55,798		62,498		6,542		1999		2006		53
3141 Fairview Park Drive	Falls Church	VA		—		5,918		40,981		7,931			7,081		47,750		54,830		5,239		1988		2006		51
2340 Dulles Corner Boulevard	Herndon	VA		—		16,345		65,379		18,370			16,129		83,965		100,094		14,093		1987		2006		40
13820 Sunrise Valley Drive	Herndon	VA		—		11,082		47,290		19,687			11,082		66,977		78,059		5,133		2007		N/A		40
2291 Wood Oak Drive	Herndon	VA		—		8,243		52,413		(742	)		8,782		51,133		59,914		5,562		1999		2006		55
2355 Dulles Corner Boulevard	Herndon	VA		—		10,365		43,876		5,232			10,365		49,109		59,473		7,504		1988		2006		40
196/198 Van Buren Street	Herndon	VA		—		7,931		43,812		6,484			8,348		49,878		58,227		7,398		1991		2006		53
2251 Corporate Park Drive	Herndon	VA		—		11,472		45,893		42			11,472		45,935		57,407		4,788		2000		2006		40
2411 Dulles Corner Park	Herndon	VA		—		7,279		46,340		3,713			7,417		49,916		57,333		6,240		1990		2006		50
13880 Dulles Corner Lane	Herndon	VA		—		7,236		39,213		640			7,373		39,716		47,089		5,938		1997		2006		55
2121 Cooperative Way	Herndon	VA		—		5,598		38,639		87			5,795		38,529		44,324		4,310		2000		2006		54
2201 Cooperative Way	Herndon	VA		—		4,809		34,093		(1,766	)		4,809		32,328		37,137		3,333		1990		2006		54
13825 Sunrise Valley Drive	Herndon	VA		—		3,794		19,365		(1,369	)		3,866		17,924		21,790		2,054		1989		2006		46
1676 International Drive	Mclean	VA		63,037		18,437		97,538		1,369			18,785		98,559		117,344		10,860		1999		2006		55
8260 Greensboro Drive	Mclean	VA		33,470		7,952		33,964		(41	)		8,102		33,773		41,875		3,690		1980		2006		52
1880 Campus Commons Drive	Reston	VA		—		6,164		28,114		155			6,281		28,152		34,433		3,072		1985		2006		52
2273 Research Boulevard	Rockville	MD		13,371		5,167		31,110		2,405			5,237		33,445		38,682		5,054		1999		2006		45
2275 Research Boulevard	Rockville	MD		13,367		5,059		29,668		2,390			5,154		31,963		37,117		4,426		1990		2006		45
2277 Research Boulevard	Rockville	MD		12,407		4,649		26,952		634			4,733		27,502		32,235		3,405		1986		2006		45
1900 Gallows Road	Vienna	VA		—		7,797		47,817		2,784			7,944		50,454		58,398		5,020		1989		2006		52
8521 Leesburg Pike	Vienna	VA		—		4,316		30,885		(357	)		4,397		30,446		34,844		3,891		1984		2006		51

NEW JERSEY/DELAWARE

220 Lake Drive East	Cherry Hill	NJ		—		2,144		8,798		1,073			2,144		9,871		12,015		2,831		1988		2001		40
457 Haddonfield Road	Cherry Hill	NJ		11,532		2,142		9,120		190			2,142		9,310		11,452		3,949		1990		1996		40
200 Lake Drive East	Cherry Hill	NJ		—		2,069		8,275		1,018			2,069		9,293		11,362		2,205		1989		2001		40
210 Lake Drive East	Cherry Hill	NJ		—		1,645		6,579		1,338			1,645		7,918		9,562		1,930		1986		2001		40
6 East Clementon Road	Gibbsboro	NJ		—		1,345		5,366		538			1,345		5,904		7,249		2,131		1980		1997		40
20 East Clementon Road	Gibbsboro	NJ		—		769		3,055		453			769		3,508		4,277		1,285		1986		1997		40
10 Foster Avenue	Gibbsboro	NJ		—		244		971		118			244		1,089		1,333		418		1983		1997		40
7 Foster Avenue	Gibbsboro	NJ		—		231		921		68			231		988		1,220		401		1983		1997		40
50 East Clementon Road	Gibbsboro	NJ		—		114		964		3			114		967		1,081		361		1986		1997		40
4 Foster Avenue	Gibbsboro	NJ		—		183		726		37			183		763		946		302		1974		1997		40
2 Foster Avenue	Gibbsboro	NJ		—		185		730		24			185		754		939		287		1974		1997		40
1 Foster Avenue	Gibbsboro	NJ		—		93		364		76			93		440		533		168		1972		1997		40
5 U.S. Avenue	Gibbsboro	NJ		—		21		81		3			21		84		105		31		1987		1997		40
5 Foster Avenue	Gibbsboro	NJ		—		9		32		26			9		58		67		21		1968		1997		40


												Gross Amount at Which Carried
					Initial Cost							December 31, 2010
									Net
									Improvements									Accumulated
									(Retirements)									Depreciation at
			Encumberances at				Building and		Since					Building and				December 31,		Year of		Year		Depreciable
Property Name	City	State	December 31, 2010		Land		Improvements		Acquisition			Land		Improvements		Total (a)		2010 (b)		Construction		Acquired		Life
1009 Lenox Drive	Lawrenceville	NJ		—		4,876		19,284		4,597			5,118		23,640		28,757		8,322		1989		1998		40
989 Lenox Drive	Lawrenceville	NJ		—		3,701		14,802		1,457			3,850		16,110		19,960		3,146		1984		2003		40
997 Lenox Drive	Lawrenceville	NJ		8,190		2,410		9,700		4,729			2,540		14,299		16,839		4,672		1987		1998		40
993 Lenox Drive	Lawrenceville	NJ		9,356		2,811		17,996		(5,366	)		2,960		12,481		15,441		4,752		1985		1998		40
1200 Lenox Drive	Lawrenceville	NJ		—		1,071		12,967		1,060			1,071		14,027		15,098		1,177		2007		N/A		40
2000 Lenox Drive	Lawrenceville	NJ		10,286		2,291		12,221		(532	)		2,684		11,296		13,980		3,019		2000		2000		40
100 Lenox Drive	Lawrenceville	NJ		—		—		—		12,081			1,134		10,947		12,081		1,213		1977		1999		40
1000 Lenox Drive	Lawrenceville	NJ		—		1,174		4,696		2,180			1,244		6,806		8,050		2,355		1982		2002		40
525 Lincoln Drive West	Marlton	NJ		—		3,727		17,620		801			3,727		18,422		22,148		4,385		1986		2004		40
1120 Executive Boulevard	Marlton	NJ		—		2,074		8,415		1,171			2,074		9,586		11,660		3,887		1987		1997		40
Three Greentree Centre	Marlton	NJ		—		323		6,024		225			324		6,249		6,572		4,773		1984		1986		40
30 Lake Center Drive	Marlton	NJ		—		1,043		4,171		530			1,043		4,702		5,744		1,346		1986		2001		40
Two Eves Drive	Marlton	NJ		—		818		3,461		157			818		3,618		4,436		1,450		1987		1997		40
Five Eves Drive	Marlton	NJ		—		703		2,819		489			703		3,308		4,011		1,280		1986		1997		40
Four B Eves Drive	Marlton	NJ		—		588		2,369		422			588		2,790		3,379		1,128		1987		1997		40
Four A Eves Drive	Marlton	NJ		—		539		2,168		142			539		2,310		2,849		947		1987		1997		40
308 Harper Drive	Moorestown	NJ		—		1,643		6,663		567			1,644		7,230		8,873		2,415		1976		1998		40
304 Harper Drive	Moorestown	NJ		—		657		2,674		369			657		3,042		3,700		1,059		1975		1998		40
700 East Gate Drive	Mt. Laurel	NJ		—		3,569		14,436		2,361			3,569		16,797		20,366		5,908		1984		1998		40
10000 Midlantic Drive	Mt. Laurel	NJ		—		3,206		12,857		1,494			3,206		14,351		17,557		5,786		1990		1997		40
15000 Midlantic Drive	Mt. Laurel	NJ		—		3,061		12,254		1,819			3,061		14,073		17,134		5,609		1991		1997		40
1000 Atrium Way	Mt. Laurel	NJ		—		2,061		8,180		3,766			2,061		11,945		14,007		4,431		1989		1997		40
1000 Howard Boulevard	Mt. Laurel	NJ		—		2,297		9,288		873			2,297		10,161		12,458		3,954		1988		1997		40
2000 Midlantic Drive	Mt. Laurel	NJ		10,243		2,202		8,823		239			2,203		9,062		11,264		3,508		1989		1997		40
701 East Gate Drive	Mt. Laurel	NJ		—		1,736		6,877		628			1,736		7,505		9,241		2,552		1986		1998		40
307 Fellowship Drive	Mt. Laurel	NJ		—		1,565		6,342		933			1,565		7,276		8,840		2,384		1981		1998		40
305 Fellowship Drive	Mt. Laurel	NJ		—		1,421		5,768		1,431			1,421		7,198		8,620		2,731		1980		1998		40
303 Fellowship Drive	Mt. Laurel	NJ		—		1,493		6,055		717			1,494		6,771		8,265		2,384		1979		1998		40
309 Fellowship Drive	Mt. Laurel	NJ		—		1,518		6,154		408			1,518		6,562		8,080		2,279		1982		1998		40
1000 Bishops Gate	Mt. Laurel	NJ		—		934		6,287		—			934		6,650		7,583		1,439		2005		2000		40
9000 Midlantic Drive	Mt. Laurel	NJ		5,666		1,472		5,895		95			1,472		5,990		7,462		2,375		1989		1997		40
161 Gaither Drive	Mt Laurel	NJ		—		1,016		4,064		813			1,016		4,877		5,893		1,399		1987		2001		40
4000 Midlantic Drive	Mt. Laurel	NJ		3,953		714		5,085		(1,408	)		714		3,677		4,391		1,604		1998		1997		40
815 East Gate Drive	Mt. Laurel	NJ		—		636		2,584		253			636		2,837		3,473		1,003		1986		1998		40
817 East Gate Drive	Mt. Laurel	NJ		—		611		2,426		360			611		2,785		3,397		991		1986		1998		40
400 Commerce Drive	Newark	DE		—		2,528		9,220		1,167			2,528		10,387		12,915		2,615		1997		2002		40
200 Commerce Drive	Newark	DE		—		911		4,414		1,018			911		5,432		6,343		1,508		1998		2002		40
100 Commerce Drive	Newark	DE		—		1,160		4,633		468			1,160		5,101		6,261		1,988		1989		1997		40
Main Street — Plaza 1000	Voorhees	NJ		—		2,732		10,942		3,051			2,732		13,992		16,725		5,582		1988		1997		40
Main Street — Piazza	Voorhees	NJ		—		696		2,802		16			696		2,818		3,514		1,184		1990		1997		40
Main Street — Promenade	Voorhees	NJ		—		531		2,052		100			532		2,151		2,683		860		1988		1997		40
920 North King Street	Wilmington	DE		—		6,141		21,140		1,192			6,141		22,332		28,473		5,472		1989		2004		30
300 Delaware Avenue	Wilmington	DE		—		6,368		13,739		2,408			6,369		16,147		22,515		4,759		1989		2004		23
Two Righter Parkway	Wilmington	DE		—		2,802		11,217		3,711			2,802		14,928		17,730		1,634		1987		2001		40
One Righter Parkway	Wilmington	DE		8,820		2,545		10,195		4,764			2,545		14,959		17,504		6,324		1989		1996		40

RICHMOND

4364 South Alston Avenue	Durham	NC		—		1,622		6,419		910			1,581		7,370		8,951		2,947		1985		1998		40
4805 Lake Brooke Drive	Glen Allen	VA		—		1,640		6,567		1,373			1,640		7,940		9,580		2,860		1996		1998		40
2812 Emerywood Parkway	Henrico	VA		—		1,069		4,281		1,024			1,069		5,305		6,374		2,010		1980		1998		40
300 Arboretum Place	Richmond	VA		11,749		5,450		21,892		3,518			5,450		25,411		30,860		8,644		1988		1998		40
7501 Boulders View Drive	Richmond	VA		—		4,669		19,699		985			4,925		20,428		25,353		1,757		1990		2007		40
7300 Beaufont Springs Drive	Richmond	VA		—		4,672		19,689		350			4,922		19,789		24,711		1,709		2000		2007		40
6800 Paragon Place	Richmond	VA		—		4,552		18,414		1,528			4,552		19,942		24,494		2,491		1986		2006		40
6802 Paragon Place	Richmond	VA		—		2,917		11,454		1,754			2,917		13,209		16,125		3,153		1989		2002		40
1025 Boulders Parkway	Richmond	VA		—		2,574		11,297		792			2,824		11,838		14,663		1,227		1994		2007		40
2100-2116 West Laburnam Avenue	Richmond	VA		—		2,482		8,846		2,854			2,482		11,700		14,182		4,058		1976		1998		40
7325 Beaufont Springs Drive	Richmond	VA		—		2,344		10,377		502			2,594		10,629		13,223		955		1999		2007		40
7401 Beaufont Springs Drive	Richmond	VA		—		2,349		10,396		315			2,599		10,461		13,060		899		1998		2007		40
6806 Paragon Place	Richmond	VA		—		—		10,288		827			403		10,712		11,115		2,033		2007		2005		40
9011 Arboretum Parkway	Richmond	VA		—		1,857		7,702		828			1,857		8,530		10,387		3,077		1991		1998		40
2511 Brittons Hill Road	Richmond	VA		—		1,202		4,820		1,815			1,202		6,636		7,837		2,557		1987		1998		40
9100 Arboretum Parkway	Richmond	VA		3,236		1,362		5,489		552			1,362		6,041		7,403		2,097		1988		1998		40
100 Gateway Centre Parkway	Richmond	VA		—		391		5,410		885			391		6,295		6,686		1,551		2001		1998		40
9200 Arboretum Parkway	Richmond	VA		2,743		985		3,973		1,332			985		5,305		6,290		1,594		1988		1998		40
9210 Arboretum Parkway	Richmond	VA		2,658		1,110		4,474		544			1,110		5,018		6,128		1,726		1988		1998		40
2201-2245 Tomlynn Street	Richmond	VA		—		1,020		4,067		430			1,020		4,498		5,517		1,574		1989		1998		40
9211 Arboretum Parkway	Richmond	VA		—		582		2,433		224			582		2,658		3,239		964		1991		1998		40
2244 Dabney Road	Richmond	VA		—		550		2,203		37			550		2,240		2,790		782		1993		1998		40
2221-2245 Dabney Road	Richmond	VA		—		530		2,123		80			530		2,204		2,733		735		1994		1998		40
2248 Dabney Road	Richmond	VA		—		512		2,049		144			512		2,193		2,705		781		1989		1998		40
2212-2224 Tomlynn Street	Richmond	VA		—		502		2,014		157			502		2,170		2,673		774		1985		1998		40
2277 Dabney Road	Richmond	VA		—		507		2,034		15			507		2,049		2,556		711		1986		1998		40


												Gross Amount at Which Carried
					Initial Cost							December 31, 2010
									Net
									Improvements									Accumulated
									(Retirements)									Depreciation at
			Encumberances at				Building and		Since					Building and				December 31,		Year of		Year		Depreciable
Property Name	City	State	December 31, 2010		Land		Improvements		Acquisition			Land		Improvements		Total (a)		2010 (b)		Construction		Acquired		Life
2246 Dabney Road	Richmond	VA		—		455		1,822		18			455		1,840		2,295		637		1987		1998		40
2161-2179 Tomlynn Street	Richmond	VA		—		423		1,695		173			423		1,868		2,291		687		1985		1998		40
2256 Dabney Road	Richmond	VA		—		356		1,427		273			356		1,700		2,056		602		1982		1998		40
2251 Dabney Road	Richmond	VA		—		387		1,552		98			387		1,650		2,037		579		1983		1998		40
2130-2146 Tomlynn Street	Richmond	VA		—		353		1,416		185			353		1,601		1,954		629		1988		1998		40
2120 Tomlynn Street	Richmond	VA		—		281		1,125		106			281		1,231		1,512		424		1986		1998		40
2240 Dabney Road	Richmond	VA		—		264		1,059		11			264		1,069		1,333		370		1984		1998		40
Boulders Land	Richmond	VA		—		1,256		—		0			1,256		—		1,256		—	NA			2007		N/A

CALIFORNIA

5780 & 5790 Fleet Street	Carlsbad	CA		—		7,073		22,907		3,297			7,516		25,761		33,277		2,973		1999		2006		55
5900 & 5950 La Place Court	Carlsbad	CA		—		3,706		11,185		1,761			3,955		12,697		16,652		1,725		1988		2006		48
5963 La Place Court	Carlsbad	CA		—		2,824		9,413		1,654			2,999		10,892		13,891		1,436		1987		2006		55
5973 Avenida Encinas	Carlsbad	CA		—		2,121		8,361		1,374			2,256		9,600		11,856		1,502		1986		2006		45
2035 Corte Del Nogal	Carlsbad	CA		—		3,261		6,077		1,038			3,499		6,878		10,376		1,199		1991		2006		39
1200 Concord Avenue	Concord	CA		17,245		6,395		24,664		(2,737	)		6,515		21,806		28,322		3,459		1984		2006		34
1220 Concord Avenue	Concord	CA		17,249		6,476		24,966		(4,211	)		6,476		20,755		27,230		3,106		1984		2006		34
155 Grand Avenue	Oakland	CA		—		13,556		54,266		4,053			13,556		58,319		71,875		5,646		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		—		(0	)		4,342		—		4,342		—		N/A		2006		N/A
16870 W Bernardo Drive	San Diego	CA		—		2,979		15,896		1,643			3,154		17,364		20,518		2,163		2002		2006		56

AUSTIN

1250 Capital of Texas Hwy South	Austin	TX		—		5,152		37,928		4,042			5,250		41,872		47,122		5,599		1984		2006		52
1301 Mopac Expressway	Austin	TX		—		4,188		41,229		309			4,250		41,476		45,727		5,533		2001		2006		55
1601 Mopac Expressway	Austin	TX		—		3,538		34,346		1,384			3,605		35,664		39,269		5,872		2000		2006		54
1501 South Mopac Expressway	Austin	TX		—		3,698		34,912		(2,195	)		3,768		32,647		36,414		3,207		1999		2006		53
1221 Mopac Expressway	Austin	TX		—		3,290		31,548		862			3,366		32,331		35,697		3,838		2001		2006		55
3711 South Mopac Expressway - II	Austin	TX		—		1,688		19,229		4,287			1,688		23,516		25,204		2,512		2007		2006		40
3711 South Mopac Expressway - I	Austin	TX		—		1,688		21,011		1,878			1,688		22,893		24,581		1,154		2007		2006		40


	Total:		$	712,246	$	686,908	$	3,700,183	$	447,020		$	697,724	$	4,136,387	$	4,834,111	$	776,078

(a)		Reconciliation of Real Estate:

		The following table reconciles the real estate investments from January 1, 2008 to December 31, 2010 (in thousands):


	2010			2009			2008
Balance at beginning of year	$	4,512,618		$	4,608,320		$	4,825,747

Additions:
Acquisitions		102,475			—			122
Capital expenditures		336,281			80,506			247,345

Less:
Dispositions		(117,263	)		(176,208	)		(464,894	)


Balance at end of year	$	4,834,111		$	4,512,618		$	4,608,320

The aggregate cost for federal income tax purposes is $4.5 billion as of December 31, 2010

(b)		Reconciliation of Accumulated Depreciation:

		The following table reconciles the accumulated depreciation on real estate investments from January 1, 2008 to December 31, 2010 (in thousands):


	2010			2009			2008
Balance at beginning of year	$	716,957		$	639,688		$	558,908

Additions:
Depreciation expense — continuing operations		133,740			141,309			144,631
Depreciation expense — discontinued operations		1,554			6,494			6,494

Less:
Dispositions		(76,173	)		(70,534	)		(70,345	)


Balance at end of year	$	776,078		$	716,957		$	639,688