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Document and Entity Information - USD ($)	6 Months Ended
Document and Entity Information - USD ($)	Jun. 30, 2011	Aug. 01, 2011	Jun. 30, 2010
Statement [Line Items]
Entity Registrant Name	BRANDYWINE REALTY TRUST
Entity Central Index Key	0000790816
Document Type	10-Q
Document Period End Date	Jun. 30, 2011
Amendment Flag	false
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q2
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		0
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Statement [Line Items]
Entity Registrant Name	BRANDYWINE OPERATING PARTNERSHIP, L.P.
Entity Central Index Key	0001060386
Document Type	10-Q
Document Period End Date	Jun. 30, 2011
Amendment Flag	false
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q2
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	Non-accelerated Filer

Consolidated Balance Sheets - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2011	Dec. 31, 2010
Real estate investments:
Rental properties	$ 4,885,041	$ 4,834,111
Accumulated depreciation	(835,713)	(776,078)
Operating real estate investments, net	4,049,328	4,058,033
Construction-in-progress	33,314	33,322
Land inventory	120,245	110,055
Total real estate investments, net	4,202,887	4,201,410
Cash and cash equivalents	733	16,565
Accounts receivable, net	14,129	16,009
Accrued rent receivable, net	103,221	95,541
Investment in real estate ventures, at equity	82,927	84,372
Deferred costs, net	113,498	106,117
Intangible assets, net	78,401	97,462
Notes receivable	19,285	18,205
Other assets	53,414	54,697
Total assets	4,668,495	4,690,378
LIABILITIES AND BENEFICIARIES' EQUITY
Mortgage notes payable	588,823	711,789
Unsecured credit facility	42,000	183,000
Unsecured term loan	183,000	183,000
Unsecured senior notes, net of discounts	1,652,198	1,352,657
Accounts payable and accrued expenses	63,263	72,235
Distributions payable	22,854	22,623
Deferred income, gains and rent	112,814	121,552
Acquired below market leases, net	25,556	29,233
Other liabilities	41,943	36,515
Total liabilities	$ 2,732,451	$ 2,712,604
Commitments and contingencies (Note 17)
Brandywine Realty Trust's equity:
Common Shares of Brandywine Realty Trust's beneficial interest, $0.01 par value; shares authorized 200,000,000; 135,536,709 and 134,601,796 issued in 2011 and 2010, respectively and 135,536,709 and 134,485,117 outstanding in 2011 and 2010, respectively	$ 1,353	$ 1,343
Additional paid-in capital	2,684,730	2,671,217
Deferred compensation payable in common stock	5,737	5,774
Common shares in treasury, at cost, 116,679 in 2010	0	(3,074)
Common shares in grantor trust, 295,852 in 2011 and 291,281 in 2010	(5,737)	(5,774)
Cumulative earnings	475,327	483,439
Accumulated other comprehensive loss	(2,474)	(1,945)
Cumulative distributions	(1,346,353)	(1,301,521)
Total Brandywine Realty Trust's equity	1,812,626	1,849,502
Non-controlling interests	123,418	128,272
Total equity	1,936,044	1,977,774
Total liabilities and equity	4,668,495	4,690,378
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Real estate investments:
Rental properties	4,885,041	4,834,111
Accumulated depreciation	(835,713)	(776,078)
Operating real estate investments, net	4,049,328	4,058,033
Construction-in-progress	33,314	33,322
Land inventory	120,245	110,055
Total real estate investments, net	4,202,887	4,201,410
Cash and cash equivalents	733	16,565
Accounts receivable, net	14,129	16,009
Accrued rent receivable, net	103,221	95,541
Investment in real estate ventures, at equity	82,927	84,372
Deferred costs, net	113,498	106,117
Intangible assets, net	78,401	97,462
Notes receivable	19,285	18,205
Other assets	53,414	54,697
Total assets	4,668,495	4,690,378
LIABILITIES AND BENEFICIARIES' EQUITY
Mortgage notes payable	588,823	711,789
Unsecured credit facility	42,000	183,000
Unsecured term loan	183,000	183,000
Unsecured senior notes, net of discounts	1,652,198	1,352,657
Accounts payable and accrued expenses	63,263	72,235
Distributions payable	22,854	22,623
Deferred income, gains and rent	112,814	121,552
Acquired below market leases, net	25,556	29,233
Other liabilities	41,943	36,515
Total liabilities	$ 2,732,451	$ 2,712,604
Commitments and contingencies (Note 17)
Redeemable limited partnership units
Redeemable limited partnership units at redemption value; 9,809,759 and 9,902,752 issued and outstanding in 2011 and 2010, respectively	$ 128,616	$ 132,855
Brandywine Realty Trust's equity:
General Partnership Capital, 135,536,709 and 134,601,796 units issued in 2011 and 2010, respectively and 135,536,709 and 134,485,117 units outstanding in 2011 and 2010, respectively	1,706,599	1,743,549
Accumulated other comprehensive loss	(2,621)	(2,080)
Total Brandywine Realty Trust's equity	1,807,428	1,844,919
Total liabilities and equity	4,668,495	4,690,378
7.50% Series D Preferred Shares \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Brandywine Realty Trust's equity:
Preferred Shares	47,912	47,912
7.50% Series C Preferred Shares
Brandywine Realty Trust's equity:
Preferred Shares	20	20
7.375% Series D Preferred Shares
Brandywine Realty Trust's equity:
Preferred Shares	23	23
7.375% Series E Preferred Shares \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Brandywine Realty Trust's equity:
Preferred Shares	$ 55,538	$ 55,538

Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2011	Dec. 31, 2010
Brandywine Realty Trust's equity:
Preferred Shares, shares authorized	20,000,000	20,000,000
Common Shares of Brandywine Realty Trust's beneficial interest, par value	$ 0.01	$ 0.01
Common Shares of Brandywine Realty Trust's beneficial interest, shares authorized	200,000,000	200,000,000
Common Shares of Brandywine Realty Trust's beneficial interest, shares issued	135,536,709	134,601,796
Common Shares of Brandywine Realty Trust's beneficial interest, shares outstanding	135,536,709	134,485,117
Common shares in treasury, at cost, shares	0	116,679
Common shares in grantor trust, shares	295,852	291,281
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Brandywine Realty Trust's equity:
General Partners' Capital account, units issued	135,536,709	134,601,796
General Partners' Capital account, units outstanding	135,536,709	134,485,117
Redeemable limited partnership, units issued	9,809,759	9,902,752
Redeemable limited partnership, units outstanding	9,809,759	9,902,752
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 (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Revenue:
Rents	$ 120,416	$ 113,006	$ 241,145	$ 227,048
Tenant reimbursements	18,969	17,234	42,025	38,050
Termination fees	1,948	1,331	2,516	3,085
Third party management fees, labor reimbursement and leasing	2,733	2,904	5,486	6,371
Other	1,341	1,022	2,439	1,943
Total revenue	145,407	135,497	293,611	276,497
Operating Expenses:
Property operating expenses	40,595	38,018	86,614	82,336
Real estate taxes	14,474	13,383	28,871	26,121
Third party management expenses	1,506	1,493	3,016	2,905
Depreciation and amortization	58,014	51,289	109,688	103,318
General and administrative expenses	5,890	6,653	12,134	12,745
Total operating expenses	120,479	110,836	240,323	227,425
Operating income	24,928	24,661	53,288	49,072
Other Income (Expense):
Interest income	421	963	862	1,828
Interest expense	(34,738)	(31,210)	(67,131)	(62,734)
Interest expense - amortization of deferred financing costs	(1,070)	(862)	(1,998)	(1,873)
Equity in income of real estate ventures	1,088	1,025	2,321	2,321
Net gain on sale of interests in real estate			2,791
Loss on early extinguishment of debt	(756)	(445)	(756)	(1,637)
Loss from continuing operations	(10,127)	(5,868)	(10,623)	(13,023)
Discontinued operations:
Income from discontinued operations	57	268	63	675
Net gain on disposition of discontinued operations	3,836		3,836	6,349
Total discontinued operations	3,893	268	3,899	7,024
Net loss	(6,234)	(5,600)	(6,724)	(5,999)
Net income from discontinued operations attributable to non-controlling interests - LP units	(78)	(6)	(78)	(150)
Net loss attributable to non-controlling interests - LP units	243	165	294	360
Net loss attributable to non-controlling interests	165	159	216	210
Net loss attributable to Brandywine Realty Trust	(6,069)	(5,441)	(6,508)	(5,789)
Distribution to Preferred Shares	(1,998)	(1,998)	(3,996)	(3,996)
Amount allocable to unvested restricted shareholders, Basic	(121)	(128)	(263)	(256)
Net loss attributable to Common Shareholders of Brandywine Realty Trust	$ (8,188)	$ (7,567)	$ (10,767)	$ (10,041)
Basic loss per Common Share:
Continuing operations	$ (0.09)	$ (0.06)	$ (0.11)	$ (0.13)
Discontinued operations	0.03	0.00	0.03	0.05
Basic loss per Common Share	(0.06)	(0.06)	(0.08)	(0.08)
Diluted loss per Common Share:
Continuing operations	(0.09)	(0.06)	(0.11)	(0.13)
Discontinued operations	0.03	0.00	0.03	0.05
Diluted loss per Common Share	$ (0.06)	$ (0.06)	$ (0.08)	$ (0.08)
Basic weighted average shares outstanding	135,342,538	131,510,924	134,962,093	130,146,853
Diluted weighted average shares outstanding	135,342,538	131,510,924	134,962,093	130,146,853
Net loss attributable to Brandywine Realty Trust
Loss from continuing operations	$ (9,884)	$ (5,703)	$ (10,329)	$ (12,663)
Income from discontinued operations	3,815	262	3,821	6,874
Net loss	(6,069)	(5,441)	(6,508)	(5,789)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue:
Rents	120,416	113,006	241,145	227,048
Tenant reimbursements	18,969	17,234	42,025	38,050
Termination fees	1,948	1,331	2,516	3,085
Third party management fees, labor reimbursement and leasing	2,733	2,904	5,486	6,371
Other	1,341	1,022	2,439	1,943
Total revenue	145,407	135,497	293,611	276,497
Operating Expenses:
Property operating expenses	40,595	38,018	86,614	82,336
Real estate taxes	14,474	13,383	28,871	26,121
Third party management expenses	1,506	1,493	3,016	2,905
Depreciation and amortization	58,014	51,289	109,688	103,318
General and administrative expenses	5,890	6,653	12,134	12,745
Total operating expenses	120,479	110,836	240,323	227,425
Operating income	24,928	24,661	53,288	49,072
Other Income (Expense):
Interest income	421	963	862	1,828
Interest expense	(34,738)	(31,210)	(67,131)	(62,734)
Interest expense - amortization of deferred financing costs	(1,070)	(862)	(1,998)	(1,873)
Equity in income of real estate ventures	1,088	1,025	2,321	2,321
Net gain on sale of interests in real estate			2,791
Loss on early extinguishment of debt	(756)	(445)	(756)	(1,637)
Loss from continuing operations	(10,127)	(5,868)	(10,623)	(13,023)
Discontinued operations:
Income from discontinued operations	57	268	63	675
Net gain on disposition of discontinued operations	3,836		3,836	6,349
Total discontinued operations	3,893	268	3,899	7,024
Net loss	(6,234)	(5,600)	(6,724)	(5,999)
Net loss attributable to Brandywine Realty Trust	(6,234)	(5,600)	(6,724)	(5,999)
Distribution to Preferred Shares	(1,998)	(1,998)	(3,996)	(3,996)
Amount allocable to unvested restricted shareholders, Basic	(121)	(128)	(263)	(256)
Net loss attributable to Common Shareholders of Brandywine Realty Trust	$ (8,353)	$ (7,726)	$ (10,983)	$ (10,251)
Basic loss per Common Share:
Continuing operations	$ (0.09)	$ (0.06)	$ (0.11)	$ (0.13)
Discontinued operations	0.03	0.00	0.03	0.05
Basic loss per Common Share	(0.06)	(0.06)	(0.08)	(0.08)
Diluted loss per Common Share:
Continuing operations	(0.09)	(0.06)	(0.11)	(0.13)
Discontinued operations	0.03	0.00	0.03	0.05
Diluted loss per Common Share	$ (0.06)	$ (0.06)	$ (0.08)	$ (0.08)
Basic weighted average shares outstanding	145,220,764	134,320,032	144,852,515	132,955,961
Diluted weighted average shares outstanding	145,220,764	134,320,032	144,852,515	132,955,961
Net loss attributable to Brandywine Realty Trust
Loss from continuing operations	$ (10,127)	$ (5,868)	$ (10,623)	$ (13,023)
Income from discontinued operations	3,893	268	3,899	7,024
Net loss	$ (6,234)	$ (5,600)	$ (6,724)	$ (5,999)

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Statement [Line Items]
Net loss	$ (6,234)	$ (5,600)	$ (6,724)	$ (5,999)
Comprehensive income (loss):
Unrealized gain (loss) on derivative financial instruments		2,355	(613)	4,171
Reclassification of realized (gains)/losses on derivative financial instruments to operations, net	51	14	74	(1)
Total comprehensive income (loss)	51	2,369	(539)	4,170
Comprehensive income (loss)	(6,183)	(3,231)	(7,263)	(1,829)
Comprehensive loss attributable to non-controlling interest	164	159	226	210
Comprehensive income (loss) attributable to Brandywine Realty Trust	(6,019)	(3,072)	(7,037)	(1,619)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Statement [Line Items]
Net loss	(6,234)	(5,600)	(6,724)	(5,999)
Comprehensive income (loss):
Unrealized gain (loss) on derivative financial instruments		2,355	(613)	4,171
Reclassification of realized (gains)/losses on derivative financial instruments to operations, net	51	14	74	(1)
Total comprehensive income (loss)	51	2,369	(539)	4,170
Comprehensive income (loss) attributable to Brandywine Realty Trust	$ (6,183)	$ (3,231)	$ (7,263)	$ (1,829)

Consolidated Statements of Beneficiaries' Equity (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Statement [Line Items]
Beginning Balance			$ 1,977,774	$ 1,921,740
Net loss	$ (6,234)	$ (5,600)	(6,724)	(5,999)
Comprehensive income	51	2,369	(539)	4,170
Issuance of Common Shares of Beneficial Interest			$ 8,272	41,692
Issuance of Common Shares of Beneficial Interest, shares			679,285
Equity issuance costs			$ (260)	(770)
Bonus Share Issuance			6	369
Vesting of Restricted Stock			(355)	(227)
Restricted Stock Amortization			1,519	1,806
Restricted Performance Units Amortization			780	424
Exercise of Stock Options			429
Stock Option Amortization			728	503
Outperformance Plan Amortization			109	246
Share Issuance from/to Deferred Compensation Plan			(16)
Share Choice Plan Issuance			(55)
Trustee Fees Paid in Shares			32	98
Cumulative Effect of Accounting Change for Variable Interest Entities				1,401
Preferred Share distributions			(3,996)	(3,996)
Distributions declared $0.30 per share in 2011 and 2010, respectively)			(41,660)	(40,450)
Ending Balance	1,936,044	1,921,007	1,936,044	1,921,007
Common Stock
Statement [Line Items]
Beginning Balance			$ 1,343	$ 1,286
Beginning Balance, shares			134,601,796	128,849,176
Issuance of Common Shares of Beneficial Interest			$ 7	$ 33
Issuance of Common Shares of Beneficial Interest, shares			679,285	3,285,345
Conversion of LP Units to Common Shares			$ 1
Conversion of LP Units to Common Shares, shares			92,992
Vesting of Restricted Stock			$ 1
Vesting of Restricted Stock, shares			85,248
Exercise of Stock Options			$ 1
Exercise of Stock Options, shares			76,887
Share Issuance from/to Deferred Compensation Plan, shares			(487)	(73)
Share Choice Plan Issuance, shares			(1,684)
Trustee Fees Paid in Shares, shares			2,672
Ending Balance	$ 1,353	$ 1,319	$ 1,353	$ 1,319
Ending Balance, shares	135,536,709	132,134,448	135,536,709	132,134,448
Preferred Stock
Statement [Line Items]
Beginning Balance			$ 43	$ 43
Beginning Balance, shares			4,300,000	4,300,000
Ending Balance	$ 43	$ 43	$ 43	$ 43
Ending Balance, shares	4,300,000	4,300,000	4,300,000	4,300,000
Additional Paid-in Capital
Statement [Line Items]
Beginning Balance			$ 2,671,217	$ 2,610,421
Issuance of Common Shares of Beneficial Interest			8,265	41,659
Equity issuance costs			(234)	(770)
Conversion of LP Units to Common Shares			1,098
Vesting of Restricted Stock			(1,820)	(1,114)
Restricted Stock Amortization			1,519	1,806
Restricted Performance Units Amortization			780	424
Exercise of Stock Options			428
Stock Option Amortization			728	503
Outperformance Plan Amortization			109	246
Share Issuance from/to Deferred Compensation Plan			(16)
Share Choice Plan Issuance			(55)
Trustee Fees Paid in Shares			32
Adjustment to Non-controlling Interest			2,679	(480)
Ending Balance	$ 2,684,730	$ 2,652,695	2,684,730	2,652,695
Deferred Compensation Payable in Common Stock
Statement [Line Items]
Beginning Balance			$ 5,774	$ 5,549
Beginning Balance, shares			291,281	255,700
Bonus Share Issuance			$ 5	$ 369
Bonus Share Issuance, shares			463	32,607
Vesting of Restricted Stock				$ 103
Vesting of Restricted Stock, shares			9,043	8,989
Share Issuance from/to Deferred Compensation Plan			$ (42)	$ (33)
Share Issuance from/to Deferred Compensation Plan, shares			(4,935)	(1,002)
Trustee Fees Paid in Shares				$ 35
Trustee Fees Paid in Shares, shares				3,020
Ending Balance	$ 5,737	$ 6,023	$ 5,737	$ 6,023
Ending Balance, shares	295,852	299,314	295,852	299,314
Common Shares in Grantor Trust
Statement [Line Items]
Beginning Balance			$ (5,774)	$ (5,549)
Bonus Share Issuance			(5)	(369)
Vesting of Restricted Stock				(103)
Share Issuance from/to Deferred Compensation Plan			42	33
Trustee Fees Paid in Shares				(35)
Ending Balance	$ (5,737)	$ (6,023)	(5,737)	(6,023)
Treasury Stock
Statement [Line Items]
Beginning Balance			$ (3,074)	$ (7,205)
Beginning Balance, shares			116,679	251,764
Bonus Share Issuance			$ 12	$ 871
Bonus Share Issuance, shares			(463)	(32,607)
Vesting of Restricted Stock			$ 3,062	$ 2,304
Vesting of Restricted Stock, shares			(116,216)	(76,598)
Trustee Fees Paid in Shares				$ 224
Trustee Fees Paid in Shares, shares				(8,412)
Ending Balance	$ 0	$ (3,806)	$ 0	$ (3,806)
Ending Balance, shares	0	134,147	0	134,147
Cumulative Earnings
Statement [Line Items]
Beginning Balance			$ 483,439	$ 501,384
Net loss			(6,508)	(5,789)
Bonus Share Issuance			(6)	(502)
Vesting of Restricted Stock			(1,598)	(1,417)
Trustee Fees Paid in Shares				(126)
Cumulative Effect of Accounting Change for Variable Interest Entities				1,439
Ending Balance	$ 475,327	$ 494,989	475,327	494,989
Cumulative Distributions
Statement [Line Items]
Beginning Balance			(1,301,521)	(1,213,359)
Preferred Share distributions			(3,996)	(3,996)
Distributions declared $0.30 per share in 2011 and 2010, respectively)			(40,836)	(39,607)
Ending Balance	(1,346,353)	(1,256,962)	(1,346,353)	(1,256,962)
Accumulated Other Comprehensive Income (Loss)
Statement [Line Items]
Beginning Balance			(1,945)	(9,138)
Comprehensive income			(529)	4,082
Ending Balance	(2,474)	(5,056)	(2,474)	(5,056)
Non-Controlling Interests
Statement [Line Items]
Beginning Balance			128,272	38,308
Net loss			(216)	(210)
Comprehensive income			(10)	88
Equity issuance costs			(26)
Conversion of LP Units to Common Shares			(1,099)
Adjustment to Non-controlling Interest			(2,679)	480
Cumulative Effect of Accounting Change for Variable Interest Entities				(38)
Distributions declared $0.30 per share in 2011 and 2010, respectively)			(824)	(843)
Ending Balance	$ 123,418	$ 37,785	$ 123,418	$ 37,785

Consolidated Statements of Beneficiaries' Equity (Unaudited) (Parenthetical) - $ / shares	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Statement [Line Items]
Distributions declared, per share	$ 0.30	$ 0.30
Cumulative Distributions
Statement [Line Items]
Distributions declared, per share	0.30	0.30
Non-Controlling Interests
Statement [Line Items]
Distributions declared, per share	$ 0.30	$ 0.30

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		9 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Sep. 30, 2009
Cash flows from operating activities:
Net loss	$ (6,234)	$ (5,600)	$ (6,724)	$ (5,999)
Adjustments to reconcile net loss to net cash from operating activities:
Depreciation and amortization			109,775	104,622
Amortization of deferred financing costs	1,070	862	1,998	1,873
Amortization of debt discount/(premium), net			529	490
Straight-line rent income			(9,447)	(5,408)
Amortization of acquired above (below) market leases to rental revenue, net			(2,636)	(3,181)
Straight-line ground rent expense			975	740
Provision for doubtful accounts			689	1,717
Non-cash compensation expense			2,051	2,492
Real estate venture income in excess of distributions			(1,618)	(1,958)
Net gain on sale of interests in real estate			(6,627)	(6,349)
Loss on early extinguishment of debt	756	445	756	1,637
Cumulative interest accretion of repayments of unsecured notes				(2,716)
Contributions from historic tax credit transaction, net of deferred costs				27,396
Changes in assets and liabilities:
Accounts receivable			2,063	161
Other assets			2,231	2,074
Accounts payable and accrued expenses			(4,500)	(7,089)
Deferred income, gains and rent			(5,048)	(5,594)
Other liabilities			3,875	(1,906)
Net cash from operating activities			88,342	103,002
Cash flows from investing activities:
Acquisition of properties			(22,032)
Sales of properties, net			5,639	10,445
Capital expenditures			(67,768)	(89,438)
Advances for purchase of tenant assets, net of repayments			(386)	(9,116)
Loan provided to an unconsolidated Real Estate Venture partner			(1,045)
Cash distributions from unconsolidated Real Estate Ventures in excess of cumulative equity income			3,063	801
Decrease in cash due to the deconsolidation of variable interest entities				(1,382)
Leasing costs			(14,724)	(11,594)
Net cash used in investing activities			(97,253)	(100,284)
Cash flows from financing activities:
Proceeds from Credit Facility borrowings			181,500	231,000
Repayments of Credit Facility borrowings			(322,500)	(163,000)
Repayments of mortgage notes payable			(122,204)	(4,467)
Proceeds from unsecured notes			321,498
Repayments of unsecured notes			(23,931)	(64,604)
Net settlement of hedge transactions			(613)
Debt financing costs			(3,662)	8
Net proceeds from issuance of shares			8,069	41,021
Exercise of stock options			429
Distributions paid to shareholders			(44,669)	(43,104)
Distributions to noncontrolling interest			(838)	(842)
Net cash from (used in) financing activities			(6,921)	(3,988)
Increase (decrease) in cash and cash equivalents			(15,832)	(1,270)
Cash and cash equivalents at beginning of period			16,565	1,567
Cash and cash equivalents at end of period	733	297	733	297
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the six months ended June 30, 2011 and 2010 of $ 859 and $6,791, respectively			67,098	80,150
Supplemental disclosure of non-cash activity:
Change in capital expenditures financed through accounts payable at period end			903	(2,739)
Change in capital expenditures financed through retention payable at period end			(5,500)	1,624
Change in unfunded tenant allowance			514	(2,418)
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)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Cash flows from operating activities:
Net loss	(6,234)	(5,600)	(6,724)	(5,999)	$ (5,999)
Adjustments to reconcile net loss to net cash from operating activities:
Depreciation and amortization			109,775	104,622
Amortization of deferred financing costs	1,070	862	1,998	1,873
Amortization of debt discount/(premium), net			529	490
Straight-line rent income			(9,447)	(5,408)
Amortization of acquired above (below) market leases to rental revenue, net			(2,636)	(3,181)
Straight-line ground rent expense			975	740
Provision for doubtful accounts			689	1,717
Non-cash compensation expense			2,051	2,492
Real estate venture income in excess of distributions			(1,618)	(1,958)
Net gain on sale of interests in real estate			(6,627)	(6,349)
Loss on early extinguishment of debt	756	445	756	1,637
Cumulative interest accretion of repayments of unsecured notes				(2,716)
Contributions from historic tax credit transaction, net of deferred costs				27,396
Changes in assets and liabilities:
Accounts receivable			2,063	161
Other assets			2,231	2,074
Accounts payable and accrued expenses			(4,500)	(7,089)
Deferred income, gains and rent			(5,048)	(5,594)
Other liabilities			3,875	(1,906)
Net cash from operating activities			88,342	103,002
Cash flows from investing activities:
Acquisition of properties			(22,032)
Sales of properties, net			5,639	10,445
Capital expenditures			(67,768)	(89,438)
Advances for purchase of tenant assets, net of repayments			(386)	(9,116)
Loan provided to an unconsolidated Real Estate Venture partner			(1,045)
Cash distributions from unconsolidated Real Estate Ventures in excess of cumulative equity income			3,063	801
Decrease in cash due to the deconsolidation of variable interest entities				(1,382)
Leasing costs			(14,724)	(11,594)
Net cash used in investing activities			(97,253)	(100,284)
Cash flows from financing activities:
Proceeds from Credit Facility borrowings			181,500	231,000
Repayments of Credit Facility borrowings			(322,500)	(163,000)
Repayments of mortgage notes payable			(122,204)	(4,467)
Proceeds from unsecured notes			321,498
Repayments of unsecured notes			(23,931)	(64,604)
Net settlement of hedge transactions			(613)
Debt financing costs			(3,662)	8
Net proceeds from issuance of shares			8,069	41,021
Exercise of stock options			429
Distributions paid to shareholders			(45,507)	(43,946)
Net cash from (used in) financing activities			(6,921)	(3,988)
Increase (decrease) in cash and cash equivalents			(15,832)	(1,270)
Cash and cash equivalents at beginning of period			16,565	1,567
Cash and cash equivalents at end of period	$ 733	$ 297	733	297
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the six months ended June 30, 2011 and 2010 of $ 859 and $6,791, respectively			67,098	80,150
Supplemental disclosure of non-cash activity:
Change in capital expenditures financed through accounts payable at period end			903	(2,739)
Change in capital expenditures financed through retention payable at period end			(5,500)	1,624
Change in unfunded tenant allowance			$ 514	(2,418)
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)

Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Supplemental disclosure:
Capitalized interest	$ 859	$ 6,791
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Supplemental disclosure:
Capitalized interest	$ 859	$ 6,791

Organization of The Parent Company and The Operating Partnership	6 Months Ended
	Jun. 30, 2011
Organization of The Parent Company and The Operating Partnership [Abstract]
ORGANIZATION OF THE PARENT COMPANY AND THE OPERATING PARTNERSHIP	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 June 30, 2011, owned a 93.2% 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 June 30, 2011, the Company owned 209 office properties, 20 industrial facilities and six mixed-use properties (collectively, the “Properties”) containing an aggregate of approximately 25.7 million net rentable square feet. In addition, as of June 30, 2011, the Company owned economic interests in 16 unconsolidated real estate ventures that contain approximately 6.1 million net rentable square feet (collectively, the “Real Estate Ventures”). 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. The Company conducts its third-party real estate management services business primarily through wholly-owned management company subsidiaries. As of June 30, 2011, the management company subsidiaries were managing properties containing an aggregate of approximately 33.7 million net rentable square feet, of which approximately 25.7 million net rentable square feet related to Properties owned by the Company and approximately 8.0 million net rentable square feet related to properties owned by third parties and Real Estate Ventures.

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2011

Summary of Significant Accounting Policies [Abstract]

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation

The consolidated financial statements have been prepared by the Company pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in the financial statements prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, all adjustments (consisting solely of normal recurring matters) for a fair statement of the financial position of the Company as of June 30, 2011, the results of its operations for the three- and six-month periods ended June 30, 2011 and 2010 and its cash flows for the six-month periods ended June 30, 2011 and 2010 have been included. The results of operations for such interim periods are not necessarily indicative of the results for a full year. These consolidated financial statements should be read in conjunction with the Parent Company’s and the Operating Partnership’s consolidated financial statements and footnotes included in their respective 2010 Annual Reports on Form 10-K filed with the SEC on February 25, 2011.

Reclassifications and Out of Period Adjustment

Certain amounts have been reclassified in prior years to conform to the current year presentation. The reclassifications are primarily due to the treatment of sold properties as discontinued operations on the statement of operations for all periods presented. In addition, the Company changed $14.0 million from leasing costs to capital expenditures in the investing section of the statements of cash flows for the six months ended June 30, 2010. This change had no effect on the subtotals within the consolidated statement of cash flows.

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

The consolidated statement of operations for the three months ended June 30, 2011 also contains an out of period depreciation and amortization expense adjustment of $4.7 million relating to intangible assets representing tenant relationships and in-place leases that should have been written off in prior periods. This resulted in the overstatement of depreciation and amortization expense of $4.7 million for both the three and six months ended June 30, 2011. During the year ended December 31, 2010, depreciation and amortization expense was overstated by $1.7 million and were understated by $1.4 million, $1.8 million, $1.7 million and $1.5 million during the years ended December 31, 2009, 2008, 2007, and 2006, respectively. As this error was not material to prior years’ consolidated financial statements and the impact of recording the error in the current period is not material to the Company’s consolidated financial statements, the Company recorded the related adjustment during the current quarter.

Principles of Consolidation

When the Company obtains an economic interest in an entity, the Company evaluates the entity to determine if the entity is deemed a variable interest entity (“VIE”), and if the Company is deemed to be the primary beneficiary, in accordance with the accounting standard for the consolidation of variable interest entities. The accounting standard for the consolidation of VIEs requires the Company to qualitatively assess if the Company was the primary beneficiary of the VIEs based on whether the Company had (i) the power to direct those matters that most significantly impacted the activities of the VIE and (ii) the obligation to absorb losses or the right to receive benefits of the VIE that could potentially be significant to the VIE. For entities that the Company has determined to be VIEs but for which it is not the primary beneficiary, its maximum exposure to loss is the carrying amount of its investments, as the Company has not provided any guarantees other than the guarantee described for PJP VII which was approximately $0.7 million at June 30, 2011 (see Note 4). Also, for all entities determined to be VIEs, the Company does not provide financial support to the real estate ventures through liquidity arrangements, guarantees or other similar commitments. When an entity is not deemed to be a VIE, the Company considers the provisions of the same accounting standard to determine whether a general partner, or the general partners as a group, controls a limited partnership or similar entity when the limited partners have certain rights. The Company consolidates (i) entities that are VIEs and of which the Company is deemed to be the primary beneficiary and (ii) entities that are non-VIEs and controlled by the Company and in which the limited partners neither have the ability to dissolve the entity or remove the Company without cause nor any substantive participating rights. Entities that the Company accounts for under the equity method (i.e., at cost, increased or decreased by the Company’s share of earnings or losses, plus contributions, less distributions) include (i) entities that are VIEs and of which the Company is not deemed to be the primary beneficiary (ii) entities that are non-VIEs which the Company does not control, but over which the Company has the ability to exercise significant influence and (iii) entities that are non-VIEs that the Company controls through its general partner status, but the limited partners in the entity have the substantive ability to dissolve the entity or remove the Company without cause or have substantive participating rights. The Company continuously assesses its determination of whether an entity is a VIE and who the primary beneficiary is, and whether or not the limited partners in an entity have substantive rights, more particularly if certain events occur that are likely to cause a change in the original determinations. The Company’s assessment includes a review of applicable documents such as, but not limited to applicable partnership agreements, real estate venture agreements, LLC agreements, management and leasing agreements to determine whether the Company has control to direct the business activities of the entities. The portion of the entities that are consolidated but not owned by the Company is presented as non-controlling interest as of and during the periods consolidated. All intercompany accounts and transactions have been eliminated in consolidation.

Use of Estimates

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

Operating Properties

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

Purchase Price Allocation

The Company allocates the purchase price of properties to net tangible and identified intangible assets acquired based on fair values. Above-market and below-market in-place lease values for acquired properties are recorded based on the present value (using an interest rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to the in-place leases and (ii) the Company’s estimate of the fair market lease rates for the corresponding in-place leases, measured over a period equal to the remaining non-cancelable term of the lease (includes the below market fixed renewal period, if applicable). 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 generally 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 generally 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 generally 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 generally 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, would be charged to expense and market rate adjustments (above or below) would be recorded to revenue.

Impairment or Disposal of Long-Lived Assets

The accounting standard for property, plant and equipment provides a single accounting model for long-lived assets classified as held-for-sale; defines the scope of businesses to be disposed of that qualify for reporting as discontinued operations; and affects 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 six month periods ended June 30, 2011 and 2010, the Company determined that no impairment charges were necessary.

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 June 30, 2011.

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 VIEs) and the Company exercises significant influence, but does not control these entities under the provisions of the entities’ governing agreements pursuant to the accounting standard for the consolidation of VIEs.

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

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 $4.1 million and $8.3 million for the three and six-month periods ended June 30, 2011 and approximately $1.8 million and $3.8 million for the three and six-month periods ended June 30, 2010, respectively. 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 $0.6 million and $1.2 million for the three and six-month periods ended June 30, 2011 and by $0.7 million and $1.6 million for the three and six-month periods ended June 30, 2010, respectively. 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 $0.4 million and $0.6 million for the three and six-month periods ended June 30, 2011 and by $0.3 million and $1.0 million for the three and six-month periods ended June 30, 2010, respectively.

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.

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 June 30, 2011, 5,787,730 common shares remained available for future awards under the 1997 Plan (including 4,550,724 shares available solely for options and share appreciation rights). Through June 30, 2011, all options awarded under the 1997 Plan had a one to ten-year term.

The Company incurred stock-based compensation expense of $1.6 million and $3.3 million during the three and six-month periods ended June 30, 2011, of which $0.4 million and $0.7 million, respectively, were capitalized as part of the Company’s review of employee salaries eligible for capitalization. The Company recognized stock-based compensation expense of $1.8 million and $3.1 million during the three and six-month periods ended June 30, 2010, of which $0.4 million and $0.6 million, respectively, were also capitalized. The expensed amounts are included in general and administrative expense on the Company’s consolidated income statement in the respective periods.

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 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.

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 June 30, 2011:

Fair Value Measurements at Reporting

Date Using:

Quoted Prices in

Active Markets for

Significant Other

Unobservable

June 30,

Identical Assets

Observable Inputs

Inputs

Description

2011

(Level 1)

(Level 2)

(Level 3)

Recurring

Assets:

Available-for-Sale Securities

284

—

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

—

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 quarterly 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 June 30, 2011.

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 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 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.

Recent Accounting Pronouncement

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

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

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

Real Estate Investments

6 Months Ended

Jun. 30, 2011

Real Estate Investments [Abstract]

REAL ESTATE INVESTMENTS

3. REAL ESTATE INVESTMENTS

As of June 30, 2011 and December 31, 2010 the gross carrying value of the Company’s rental properties was as follows (in thousands):


	June 30, 2011		December 31, 2010

Land	$	698,982	$	697,724
Building and improvements		3,722,243		3,693,579
Tenant improvements		463,816		442,808

	$	4,885,041	$	4,834,111

Acquisitions and Dispositions

On March 28, 2011, the Company acquired two office properties totaling 126,496 of net rentable square feet in Glen Allen, Virginia known as Overlook I and II for $12.6 million. The acquired properties are currently 100% leased. The Company funded the acquisition price through an advance under its $600.0 million Credit Facility (the “Credit Facility”) and with available corporate funds. The Company recognized a nominal amount of acquisition related costs which are included as part of general and administrative expenses in the Company’s consolidated statements of operations.

On January 20, 2011, the Company acquired a one acre parcel of land in Philadelphia, Pennsylvania for $9.3 million. The Company funded the cost of this acquisition with available corporate cash and a draw on its Credit Facility. The Company capitalized $0.5 million of acquisition related costs as part of land inventory in its consolidated balance sheet. The Company expects to contribute the acquired property into a real estate venture in return for a 50% limited interest in the partnership. The real estate venture is expected to be formed to construct a mixed-use development property in the city of Philadelphia. The Company received $4.9 million from the prospective partner in anticipation of the real estate venture formation. The amount received is included as part of other liabilities in the Company’s consolidated balance sheet as of June 30, 2011.

On August 5, 2010, the Company acquired a 53 story Class A office tower at 1717 Arch Street (“Three Logan Square”) in Philadelphia, Pennsylvania, together with related ground tenancy rights under a long-term ground lease, from BAT Partners, L.P. Three Logan Square contains approximately 1.0 million of net rentable square feet and is 67.2% leased as of June 30, 2011. The Company acquired Three Logan Square for approximately $129.0 million funded through a combination of $51.2 million in cash and the issuance of 7,111,112 units of a newly-established class of its limited partnership interest in the Operating Partnership designated as “Class F (2010) Units.” The Class F (2010) Units do not accrue a dividend and are not entitled to income or loss allocations prior to the first anniversary of the closing. Total cash paid after the assumption of security deposit obligations of existing tenants in the property of $0.9 million amounted to $50.3 million. The assumed security deposit obligation is included in the tenant security deposits and deferred rents in the Company’s consolidated balance sheets. The Company funded the cash portion of the acquisition price through an advance under its Credit Facility and with available corporate funds.

For purposes of computing the total purchase price, the Class F (2010) Units were valued based on the closing market price of the Parent Company’s common shares on the acquisition date of $11.54 less the annual dividend rate per share of $0.60 since these units do not accrue a dividend prior to the first anniversary. The Class F (2010) Units 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 (in thousands):


	August 5,
	2010

Building and tenant improvements	$	98,188
Intangible assets acquired		28,856
Below market lease liabilities assumed		(683	)

Total	$	126,361

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


			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 prior year consolidated statements of operations.

The unaudited pro forma information below summarizes the Company’s combined results of operations for the three and six-months ended June 30, 2010 as though the acquisition of Three Logan Square was completed on January 1, 2010. 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).


	Three-months			Six-months
	ended June 30, 2010			ended June 30, 2010

Pro forma revenues	$	142,426		$	290,467
Pro forma loss from continuing operations		(5,615	)		(12,429	)
Pro forma net loss attributable to common shareholders		(7,314	)		(9,448	)

Loss per common share from continuing operations:
Basic — as reported	$	(0.06	)	$	(0.13	)

Basic — as pro forma	$	(0.06	)	$	(0.13	)


Diulted — as reported	$	(0.06	)	$	(0.13	)

Diulted — as pro forma	$	(0.06	)	$	(0.13	)


Loss per common share:
Basic — as reported	$	(0.06	)	$	(0.08	)

Basic — as pro forma	$	(0.06	)	$	(0.08	)


Diulted — as reported	$	(0.06	)	$	(0.08	)

Diulted — as pro forma	$	(0.06	)	$	(0.08	)

On June 27, 2011, the Company sold Three Greentree Center, a 69,300 net rentable square feet office property located in Marlton, New Jersey, for a sales price of $5.9 million. The property was 13.9% occupied as of the date of sale. This sale is included in discontinued operations (see Note 10).

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

Investment in Unconsolidated Ventures

6 Months Ended

Jun. 30, 2011

Investment in Unconsolidated Ventures [Abstract]

INVESTMENT IN UNCONSOLIDATED VENTURES

4. INVESTMENT IN UNCONSOLIDATED VENTURES

As of June 30, 2011, the Company had an aggregate investment of approximately $82.9 million in 16 unconsolidated Real Estate Ventures. The Company formed these ventures with unaffiliated third parties, or acquired interests in them, to develop or manage office properties or to acquire land in anticipation of possible development of office properties. As of June 30, 2011, 14 of the Real Estate Ventures owned 49 office buildings that contain an aggregate of approximately 6.1 million net rentable square feet; one Real Estate Venture owned three acres of undeveloped parcel of 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 10% to 65%, subject to specified priority allocations of distributable cash 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 distributions of excess financing proceeds. The Company reflected its acquisition of this Real Estate Venture interest at its relative fair value as of the date of the merger. The difference between allocated cost and the underlying equity in the net assets of the investee is accounted for as if the entity were consolidated (i.e., allocated to the Company’s relative share of assets and liabilities with an adjustment to recognize equity in earnings for the appropriate additional 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 following is a summary of the financial position of the Real Estate Ventures as of June 30, 2011 and December 31, 2010 (in thousands):


	June 30,		December 31,
	2011		2010

Net property	$	726,254	$	804,705
Other assets		99,589		105,576
Other liabilities		39,583		44,509
Debt		683,679		748,387
Equity		102,581		117,385
Company’s share of equity (Company’s basis)		82,927		84,372

The following is a summary of results of operations of the Real Estate Ventures for the three and six-month periods ended June 30, 2011 and 2010 (in thousands):


	Three-month periods					Six-month periods
	ended June 30,					ended June 30,
	2011			2010		2011			2010

Revenue	$	32,722		$	30,528	$	72,398		$	54,598
Operating expenses		14,370			10,305		30,544			19,001
Interest expense, net		9,550			9,270		21,673			17,008
Depreciation and amortization		8,487			8,302		18,968			14,524
Net (loss) income		(315	)		2,651		(1,213	)		4,065
Company’s share of income (Company’s basis)		1,088			1,025		2,321			2,321

As of June 30, 2011, the Company had guaranteed repayment of approximately $0.7 million of loans on behalf of a 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.

On June 29, 2011, one of the unconsolidated Real Estate Ventures sold its only office building, a 347,620 net rentable square feet office property located in Conshohocken, Pennsylvania, for a sales price of $86.7 million. The property was 87.0% occupied as of the date of sale. The Company had a three percent ownership percentage in the Real Estate Venture and recognized $0.6 million of income from the sale as part of its equity in income from the Real Estate Venture.

In November 2010, the Company acquired a 25% interest in two partnerships which own two office buildings in Philadelphia, Pennsylvania. The other partner holds the remaining 75% interest in each of the two partnerships. In connection with the closing, the Company contributed an initial $5.0 million, out of a total of $25.0 million of committed preferred equity. The Company expects to contribute the remaining $20.0 million by December 2012. Failure to fund the remaining commitment will result in an adjustment to the Company’s 25% limited partnership ownership percentage.

Deferred Costs

6 Months Ended

Jun. 30, 2011

Deferred Costs [Abstract]

Deferred Costs

5. DEFERRED COSTS

As of June 30, 2011 and December 31, 2010, the Company’s deferred costs were comprised of the following (in thousands):


	June 30, 2011
			Accumulated			Deferred Costs,
	Total Cost		Amortization			net

Leasing Costs	$	133,734	$	(48,223	)	$	85,511
Financing Costs		39,605		(11,618	)		27,987

Total	$	173,339	$	(59,841	)	$	113,498


	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

During the three and six-month periods ended June 30, 2011, the Company capitalized internal direct leasing costs of $1.7 million and $3.2 million, and $1.3 million and $3.1 million during the three and six-months ended June 30, 2010, respectively, in accordance with the accounting standard for the capitalization of leasing costs.

Intangible Assets

6 Months Ended

Jun. 30, 2011

Intangible Assets and Liabilities [Abstract]

INTANGIBLE ASSETS

6. INTANGIBLE ASSETS

As of June 30, 2011 and December 31, 2010, the Company’s intangible assets were comprised of the following (in thousands):


	June 30, 2011
			Accumulated			Intangible Assets,
	Total Cost		Amortization			net

In-place lease value	$	97,523	$	(61,390	)	$	36,133
Tenant relationship value		80,242		(46,041	)		34,201
Above market leases acquired		16,718		(8,651	)		8,067

Total	$	194,483	$	(116,082	)	$	78,401


Below market leases acquired	$	66,402	$	(40,846	)	$	25,556


	December 31, 2010
			Accumulated			Intangible Assets,
	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

As of June 30, 2011, the Company’s annual amortization for its intangible assets/liabilities were as follows (in thousands, and assuming no early lease terminations):


	Assets		Liabilities
2011 (six months remaining)	$	14,510	$	3,581
2012		20,705		6,447
2013		12,452		5,902
2014		9,481		4,334
2015		6,717		2,158
Thereafter		14,536		3,134

Total	$	78,401	$	25,556

Debt Obligations

6 Months Ended

Jun. 30, 2011

Debt Obligations [Abstract]

DEBT OBLIGATIONS

7. DEBT OBLIGATIONS

The following table sets forth information regarding the Company’s consolidated debt obligations outstanding at June 30, 2011 and December 31, 2010 (in thousands):

MORTGAGE DEBT:


							Effective
	June 30,			December 31,			Interest			Maturity
Property / Location	2011			2010			Rate			Date

Arboretum I, II, III & V	$	—		$	20,386			7.59	% (a)	Jul-11
Midlantic Drive/Lenox Drive/DCC I		—			56,514			8.05	%(b)	Oct-11
Research Office Center		—			39,145			5.30	%(c), (d)	Oct-11
Concord Airport Plaza		33,914			34,494			5.55	%(d)	Jan-12
Newtown Square/Berwyn Park/Libertyview		57,334			58,102			7.25	%	May-13
Southpoint III		2,249			2,597			7.75	%	Apr-14
Tysons Corner		95,698			96,507			5.36	%(d)	Aug-15
Two Logan Square		89,800			89,800			7.57	%	Apr-16
One Logan Square		60,000			60,000			4.50	% (e)	Jul-16
IRS Philadelphia Campus		205,676			208,366			6.95	%	Sep-30
Cira South Garage		45,372			46,335			7.11	%	Sep-30

Principal balance outstanding		590,043			712,246
Plus: unamortized fixed-rate debt premiums (discounts), net		(1,220	)		(457	)

Total mortgage indebtedness	$	588,823		$	711,789


UNSECURED DEBT:
$345.0M 3.875% Guaranteed Exchangeable Notes due 2026		59,835			59,835			5.50	% (f)	Oct-11
Bank Term Loan		183,000			183,000			LIBOR + 0.800	% (g)	Jun-12
Credit Facility		42,000			183,000			LIBOR + 0.725	% (g)	Jun-12
$300.0M 5.750% Guaranteed Notes due 2012		153,694			175,200			5.73	%	Apr-12
$250.0M 5.400% Guaranteed Notes due 2014		242,681			242,681			5.53	%	Nov-14
$250.0M 7.500% Guaranteed Notes due 2015		248,585			250,000			7.77	%	May-15
$250.0M 6.000% Guaranteed Notes due 2016		250,000			250,000			5.95	%	Apr-16
$300.0M 5.700% Guaranteed Notes due 2017		300,000			300,000			5.68	%	May-17
$325.0M 4.950% Guaranteed Notes due 2018		325,000			—			5.14	%	Apr-18
Indenture IA (Preferred Trust I)		27,062			27,062			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		1,883,405			1,722,326
Less: unamortized exchangeable debt discount		(362	)		(906	)
unamortized fixed-rate debt discounts, net		(5,845	)		(2,763	)

Total unsecured indebtedness	$	1,877,198		$	1,718,657


Total Debt Obligations	$	2,466,021		$	2,430,446


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

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

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

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


(e)		This mortgage is subject to an interest rate floor of 4.50% on a monthly basis. On July 11, 2011, the Company prepaid the balance of the loan without penalty (see Note 18).

(f)		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.

(g)		On March 31, 2011, the maturity dates of the Bank Term Loan and the Credit Facility were extended to June 29, 2012 from June 29, 2011. On June 29, 2011, the Company paid a total extension fee amounting to $1.2 million which is equal to 15 basis points of the outstanding principal balance of the Bank Term Loan and of the committed amount under the Credit Facility. The extension of the maturity dates was at the Company’s option under the Bank Term Loan and the Credit Facility agreements. There were no changes in the terms and conditions of the loan agreements as a result of the maturity date extensions.

During the six-month periods ended June 30, 2011 and 2010, the Company’s weighted-average effective interest rate on its mortgage notes payable was 6.50% and 6.43%, respectively.

During the six-months ended June 30, 2011, the Company repurchased $22.9 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
2012 5.750% Notes	$	22,331	$	21,506	$	(821	)	$	82
2015 7.500% Notes		1,600		1,415		(211	)		8

	$	23,931	$	22,921	$	(1,032	)	$	90

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

The Company utilizes credit facility borrowings for general business purposes, including the acquisition, development and redevelopment of properties and the repayment of other debt. 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 June 30, 2011, the Company had $42.0 million of borrowings and $10.3 million in letters of credit outstanding, leaving $547.7 million of unused availability under the Credit Facility. During the six-month periods ended June 30, 2011 and 2010, the weighted-average interest rate on Credit Facility borrowings was 1.01%. As of June 30, 2011 and 2010, the weighted average interest rate on the Credit Facility was 0.99% and 1.07%, 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 June 30, 2011.

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 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 both at June 30, 2011 and December 31, 2010, 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 or a combination of both at the Company’s option. 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 $0.4 million at June 30, 2011 and $0.9 million at December 31, 2010, respectively, and will be amortized through October 15, 2011. The effective interest rate at June 30, 2011 and December 31, 2010 was 5.5%. The Company recognized contractual coupon interest of $0.6 million and $1.2 million for the three and six-month periods ended June 30, 2011 and $0.8 million and $1.9 million for the three and six-month periods ended June 30, 2010, respectively. In addition, the Company recognized interest expense on amortization of debt discount of $0.3 million and $0.6 million during the three and six-month periods ended June 30, 2011 and $0.4 million and $0.9 million during the three and six-month periods ended June 30, 2010, respectively. Debt discount write-offs resulting from debt repurchases amounted to $0.5 million and $1.6 million for the three and six-month periods ended June 30, 2010. There were no repurchases of the notes during the three and six-month periods ended June 30, 2011.

As of June 30, 2011, the Company’s aggregate scheduled principal payments of debt obligations, excluding amortization of discounts and premiums, were as follows (in thousands):


2011	$	6,339
2012		424,630
2013		67,037
2014		255,016
2015		348,742
Thereafter		1,371,684

Total principal payments		2,473,448
Net unamortized premiums/(discounts)		(7,427	)

Outstanding indebtedness	$	2,466,021

Fair Value of Financial Instruments

6 Months Ended

Jun. 30, 2011

Fair Value of Financial Instruments [Abstract]

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 June 30, 2011 and December 31, 2010, respectively. The discount rate used in calculating fair value is the sum of the current risk free rate and the risk premium on the date of measurement of the instruments or obligations. Considerable judgment is necessary to interpret market data and to develop the related estimates of fair value. Accordingly, the estimates presented are not necessarily indicative of the amounts that the Company could realize upon disposition. The use of different estimation methodologies may have a material effect on the estimated fair value amounts. The Company believes that the carrying amounts reflected in the consolidated balance sheets at June 30, 2011 and December 31, 2010 approximate the fair values for cash and cash equivalents, accounts receivable, other assets, accounts payable and accrued expenses.

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


	June 30, 2011					December 31, 2010
	Carrying			Fair		Carrying			Fair
	Amount			Value		Amount			Value

Mortgage payable, net of discounts	$	588,823		$	602,815	$	711,789		$	726,348
Unsecured notes payable, net of discounts	$	1,573,588		$	1,702,493	$	1,274,047		$	1,338,743
Variable rate debt instruments	$	303,610		$	295,131	$	444,610		$	432,556
Notes receivable	$	32,255	(a)	$	29,995	$	31,216	(a)	$	28,921


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

Risk Management and Use of Financial Instruments	6 Months Ended
Risk Management and Use of Financial Instruments	Jun. 30, 2011
Risk Management and Use of Financial Instruments [Abstract]
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. Vacancy rates may increase through 2011 and possibly beyond as the current economic climate negatively impacts tenants.. 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 including the potential impact of the government’s inability to resolve the debt limit issue, 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 affect 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 June 30, 2011. Management continuously monitors the Company’s compliance with and anticipated compliance with the covenants. Certain of the covenants restrict management’s ability to obtain alternative sources of capital. While the Company currently believes it will remain in compliance with its covenants, in the event of a continued slow-down and continued crisis in the credit markets, the Company may not be able to remain in compliance with such covenants and if the lender would not provide a waiver, it could result in an event of default. Use of Derivative Financial Instruments The Company’s use of derivative instruments is limited to the utilization of interest rate agreements or other instruments to manage interest rate risk exposures and not for speculative purposes. The principal objective of such arrangements is to minimize the risks and/or costs associated with the Company’s operating and financial structure, as well as to hedge specific transactions. The counterparties to these arrangements are major financial institutions with which the Company and its affiliates may also have other financial relationships. The Company is potentially exposed to credit loss in the event of non-performance by these counterparties. However, because of the high credit ratings of the counterparties, the Company does not anticipate that any of the counterparties will fail to meet these obligations as they come due. The Company does not hedge credit or property value market risks through derivative financial instruments. The Company formally assesses, both at inception of the hedge and on an on-going basis, whether each derivative is highly-effective in offsetting changes in cash flows of the hedged item. If management determines that a derivative is not highly-effective as a hedge or if a derivative ceases to be a highly-effective hedge, the Company will discontinue hedge accounting prospectively. The related ineffectiveness would be charged to the consolidated statement of operations. The valuation of these instruments is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. To comply with the provisions of the accounting standard for fair value measurements and disclosures, the Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. On March 31, 2011, in anticipation of the offering of $325.0 million of 4.95% unsecured guaranteed notes due April 15, 2018, the Company entered into seven intra-day treasury lock agreements. The treasury lock agreements were designated as cash flow hedges on interest rate risk and qualified for hedge accounting. The total notional amount of the treasury lock agreements were $230.0 million for an expiration of 7 years at treasury rates of 2.891%, 2.873%, and 2.858% and had a fair value of $0.6 million at March 31, 2011. The agreements were also settled in the same day upon completion of the debt offering at a total expense of $0.6 million. This expense was recorded as a component of accumulated other comprehensive income in the accompanying consolidated balance sheet and will be amortized over the term of the note. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, in connection with the intra-day treasury lock agreement that the Company entered into and the remaining interest swaps which matured in October 18, 2010, the Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. The changes in fair values of the hedges during the three and six months ended June 30, 2010 were included in other liabilities and accumulated other comprehensive income in the accompanying balance sheet. 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 the three and six-month periods ended June 30, 2011 and 2010. Conditions 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 under their leases.

Discontinued Operations

6 Months Ended

Jun. 30, 2011

Discontinued Operations [Abstract]

DISCONTINUED OPERATIONS

10. DISCONTINUED OPERATIONS

For the three and six-month periods ended June 30, 2011, income from discontinued operations relates to one property that the Company sold during 2011. The following table summarizes the revenue and expense information for the property classified as discontinued operations for the three and six-month periods ended June 30, 2011 (in thousands):


	Three-month period		Six-month period
	ended June 30, 2011		ended June 30, 2011
Revenue:
Rents	$	199	$	475
Tenant reimbursements		18		83
Other		—		(78	)

Total revenue		217		480

Expenses:
Property operating expenses		101		260
Real estate taxes		19		70
Depreciation and amortization		40		87

Total operating expenses		160		417

Income from discontinued operations before gain on sale of interests in real estate		57		63

Net gain on disposition of discontinued operations		3,836		3,836

Income from discontinued operations	$	3,893	$	3,899

For the three and six-month periods ended June 30, 2010, income from discontinued operations relates to nine properties that the Company sold since January 1, 2010 through June 30, 2011. The following table summarizes the revenue and expense information for properties classified as discontinued operations for the three and six-month periods ended June 30, 2010 (in thousands):


	Three-month period		Six-month period
	ended June 30, 2010		ended June 30, 2010
Revenue:
Rents	$	1,526	$	2,993
Tenant reimbursements		642		1,357
Other		2		2

Total revenue		2,170		4,352

Expenses:
Property operating expenses		751		1,606
Real estate taxes		315		631
Depreciation and amortization		836		1,440

Total operating expenses		1,902		3,677

Income from discontinued operations before gain on sale of interests in real estate		268		675

Net gain on disposition of discontinued operations		—		6,349

Income from discontinued operations	$	268	$	7,024

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	6 Months Ended
Non Controlling Interests in The Parent Company	Jun. 30, 2011
Non Controlling Interests in the Parent Company [Abstract]
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. As of June 30, 2011 and December 31, 2010, the aggregate book value of the non-controlling interests associated with the redeemable common limited partnership interests in the accompanying consolidated balance sheet of the Parent Company was $123.4 million and $128.3 million, respectively. The Parent Company believes that the aggregate settlement value of these interests (based on the number of units outstanding and the closing price of the common shares on the balance sheet date) was approximately $113.7 million and $115.4 million, respectively.

Beneficiaries Equity of the Parent Company

6 Months Ended

Jun. 30, 2011

Beneficiaries Equity of The Parent Company [Abstract]

BENEFICIARIES' EQUITY OF THE PARENT COMPANY

12. 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):


	Three-month periods ended June 30,
	2011						2010
	Basic			Diluted			Basic			Diluted

Numerator
Loss from continuing operations	$	(10,127	)	$	(10,127	)	$	(5,868	)	$	(5,868	)

Net loss from continuing operations attributable to non-controlling interests		243			243			165			165
Amount allocable to unvested restricted shareholders		(121	)		(121	)		(128	)		(128	)
Preferred share dividends		(1,998	)		(1,998	)		(1,998	)		(1,998	)

Loss from continuing operations available to common shareholders		(12,003	)		(12,003	)		(7,829	)		(7,829	)

Income (loss) from discontinued operations		3,893			3,893			268			268
Discontinued operations attributable to non-controlling interests		(78	)		(78	)		(6	)		(6	)

Discontinued operations attributable to common shareholders		3,815			3,815			262			262


Net loss attributable to common shareholders	$	(8,188	)	$	(8,188	)	$	(7,567	)	$	(7,567	)


Denominator
Weighted-average shares outstanding		135,342,538			135,342,538			131,510,924			131,510,924

Earnings per Common Share:
Loss from continuing operations attributable to common shareholders	$	(0.09	)	$	(0.09	)	$	(0.06	)	$	(0.06	)
Discontinued operations attributable to common shareholders		0.03			0.03			—			—

Net loss attributable to common shareholders	$	(0.06	)	$	(0.06	)	$	(0.06	)	$	(0.06	)


	Six-month periods ended June 30,
	2011						2010
	Basic			Diluted			Basic			Diluted

Numerator
Loss from continuing operations	$	(10,623	)	$	(10,623	)	$	(13,023	)	$	(13,023	)

Net loss from continuing operations attributable to non-controlling interests		294			294			360			360
Amount allocable to unvested restricted shareholders		(263	)		(263	)		(256	)		(256	)
Preferred share dividends		(3,996	)		(3,996	)		(3,996	)		(3,996	)

Loss from continuing operations available to common shareholders		(14,588	)		(14,588	)		(16,915	)		(16,915	)

Income (loss) from discontinued operations		3,899			3,899			7,024			7,024
Discontinued operations attributable to non-controlling interests		(78	)		(78	)		(150	)		(150	)

Discontinued operations attributable to common shareholders		3,821			3,821			6,874			6,874


Net loss attributable to common shareholders	$	(10,767	)	$	(10,767	)	$	(10,041	)	$	(10,041	)


Denominator
Weighted-average shares outstanding		134,962,093			134,962,093			130,146,853			130,146,853

Earnings per Common Share:
Loss from continuing operations attributable to common shareholders	$	(0.11	)	$	(0.11	)	$	(0.13	)	$	(0.13	)
Discontinued operations attributable to common shareholders		0.03			0.03			0.05			0.05

Net loss attributable to common shareholders	$	(0.08	)	$	(0.08	)	$	(0.08	)	$	(0.08	)

Redeemable limited partnership units totaling 9,809,759 and 2,809,108 as of June 30, 2011 and 2010, respectively, were excluded from the diluted earnings per share computations because their effect would have been anti-dilutive.

The contingent securities/share 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 six months ended June 30, 2011 and 2010, earnings representing nonforfeitable dividends as noted in the table above were allocated to the unvested restricted shares issued to the Company’s executives and other employees under the 1997 Plan.

Common and Preferred Shares

On June 1, 2011, the Parent Company declared a distribution of $0.15 per common share, totaling $20.5 million, which was paid on July 20, 2011 to shareholders of record as of July 6, 2011. On June 1, 2011, the Parent Company declared distributions on its Series C Preferred Shares and Series D Preferred Shares to holders of record as of June 30, 2011. These shares are entitled to a preferential return of 7.50% and 7.375%, respectively. Distributions paid on July 15, 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. The Company may sell common shares in amounts and at times to be determined by the Parent Company. Actual sales will depend on a variety of factors as determined by the Company, including market conditions, the trading price of its common shares and determinations by the Parent Company of the appropriate sources of funding. In conjunction with the Offering Program, the Parent Company engages sales agents who receive compensation, in aggregate, of up to 2% of the gross sales price per share sold. During the six months ended June 30, 2011, the Parent Company sold 679,285 shares under this program at an average sales price of $12.18 per share resulting in net proceeds of $8.0 million. The Parent Company contributed the net proceeds from the sale of its shares to the Operating Partnership in exchange for the issuance of 679,285 common partnership units to the Parent Company. The Operating Partnership used the net proceeds from the sales contributed by the Parent Company to repay balances on its Credit Facility and for general corporate purposes. From the inception of the Offering Program in March 2010 through June 30, 2011, the Parent Company had sold 6,421,553 shares under this program resulting in 8,578,447 remaining shares available for sale.

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 six-month period ended June 30, 2011. As of June 30, 2011, the Parent Company may purchase an additional 0.5 million shares under the program. 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

6 Months Ended

Jun. 30, 2011

Partners Equity of The Operating Partnership [Abstract]

PARTNERS' EQUITY OF THE OPERATING PARTNERSHIP

13. 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):


	Three-month periods ended June 30,
	2011						2010
	Basic			Diluted			Basic			Diluted

Numerator
Loss from continuing operations	$	(10,127	)	$	(10,127	)	$	(5,868	)	$	(5,868	)

Amount allocable to unvested restricted unitholders		(121	)		(121	)		(128	)		(128	)
Preferred unit dividends		(1,998	)		(1,998	)		(1,998	)		(1,998	)

Loss from continuing operations available to common unitholders		(12,246	)		(12,246	)		(7,994	)		(7,994	)

Discontinued operations attributable to common unitholders		3,893			3,893			268			268


Net loss attributable to common unitholders	$	(8,353	)	$	(8,353	)	$	(7,726	)	$	(7,726	)


Denominator
Weighted-average units outstanding		145,220,764			145,220,764			134,320,032			134,320,032

Earnings per Common Share:
Loss from continuing operations attributable to common unitholders	$	(0.09	)	$	(0.09	)	$	(0.06	)	$	(0.06	)
Discontinued operations attributable to common unitholders		0.03			0.03			—			—

Net loss attributable to common unitholders	$	(0.06	)	$	(0.06	)	$	(0.06	)	$	(0.06	)


	Six-month periods ended June 30,
	2011						2010
	Basic			Diluted			Basic			Diluted

Numerator
Loss from continuing operations	$	(10,623	)	$	(10,623	)	$	(13,023	)	$	(13,023	)

Amount allocable to unvested restricted unitholders		(263	)		(263	)		(256	)		(256	)
Preferred unit dividends		(3,996	)		(3,996	)		(3,996	)		(3,996	)

Loss from continuing operations available to common unitholders		(14,882	)		(14,882	)		(17,275	)		(17,275	)

Discontinued operations attributable to common unitholders		3,899			3,899			7,024			7,024


Net loss attributable to common unitholders	$	(10,983	)	$	(10,983	)	$	(10,251	)	$	(10,251	)


Denominator
Weighted-average units outstanding		144,852,515			144,852,515			132,955,961			132,955,961

Earnings per Common Share:
Loss from continuing operations attributable to common unitholders	$	(0.11	)	$	(0.11	)	$	(0.13	)	$	(0.13	)
Discontinued operations attributable to common unitholders		0.03			0.03			0.05			0.05

Net loss attributable to common unitholders	$	(0.08	)	$	(0.08	)	$	(0.08	)	$	(0.08	)

Unvested restricted units 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 six-months ended June 30, 2011 and 2010, earnings representing nonforfeitable dividends as noted in the table above were allocated to the unvested restricted units.

Common Partnership Unit and Preferred Mirror Units

On June 1, 2011, the Operating Partnership declared a distribution of $0.15 per common partnership unit, totaling $20.5 million, which was paid on July 20, 2011 to unitholders of record as of July 6, 2011.

On June 1, 2011, the Operating Partnership declared distributions on its Series D Preferred Mirror Units and Series E Preferred Mirror Units to holders of record as of June 30, 2011. These units are entitled to a preferential return of 7.50% and 7.375%, respectively. Distributions paid on July 15, 2011 to holders of Series D Preferred Mirror Units and Series E Preferred Mirror Units totaled $0.9 million and $1.1 million, respectively.

During the six-month period ended June 30, 2011, the Parent Company contributed net proceeds amounting to $8.0 million from the sale of 679,285 common shares under its Offering Program to the Operating Partnership in exchange for the issuance of 679,285 common partnership units to the Parent Company. The Operating Partnership used the net proceeds from the sales to repay balances on its unsecured revolving Credit Facility and for general corporate purposes.

The Operating Partnership issued 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 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 Parent Company common shares.

Common Unit Repurchases

The Parent Company did not purchase any shares during the six months ended June 30, 2011 and accordingly, during the six months ended June 30, 2011, the Operating Partnership did not repurchase any units in connection with the Parent Company’s share repurchase program.

Share Based and Deferred Compensation

6 Months Ended

Jun. 30, 2011

Share Based and Deferred Compensation [Abstract]

SHARE BASED AND DEFERRED COMPENSATION

14. SHARE BASED AND DEFERRED COMPENSATION

Stock Options

At June 30, 2011, the Parent Company had 3,642,965 options outstanding under its shareholder approved equity incentive plan. There were 1,311,943 options unvested as of June 30, 2011 and $3.1 million of unrecognized compensation expense associated with these options to be recognized over a weighted average of 2.0 years. During the three and six-months ended June 30, 2011, the Company recognized compensation expense related to unvested options of $0.4 million and $0.7 million, of which $0.1 million and $0.2 million, respectively, were capitalized as part of the Company’s review of employee salaries eligible for capitalization. During the three and six-months ended June 30, 2010, the Company recognized $0.3 million and $0.5 million of compensation expense, respectively, and of which nominal amounts of compensation expense were capitalized. The recognized compensation expenses are included as part of general and administrative expense in the Company’s consolidated statements of operations.

Option activity as of June 30, 2011 and changes during the six months ended June 30, 2011 were as follows:


				Weighted		Weighted Average
				Average		Remaining Contractual		Aggregate Intrinsic
	Shares			Exercise Price		Term (in years)		Value
Outstanding at January 1, 2011		3,116,611		$	14.56		7.81	$	(9,080,625	)
Granted		603,241			11.89		9.68		(180,972	)
Exercised		(76,887	)		2.91


Outstanding at June 30, 2011		3,642,965		$	14.37		7.70	$	(10,115,971	)


Vested/Exercisable at June 30, 2011		2,331,021		$	16.75		7.05	$	(11,802,863	)

On March 2, 2011, the Compensation Committee of the Company’s Board of Trustees awarded 603,241 options to the Company’s executives. The options vest ratably over three years and have a ten year term. The vesting of the options is also subject to acceleration upon a change in control or if the recipient of the award were to die, become disabled, be terminated without cause or retire in a qualifying retirement prior to the vesting date. Qualifying retirement for options granted on March 2, 2011 as provided under the 1997 Plan means the recipient’s voluntary termination of employment after reaching age 57 and accumulating at least 15 years of service with the Company. On May 24, 2011, the Compensation Committee modified these options in respect to 101,437 shares awarded to one of the Company’s executives. The modification, with the said executive’s approval, provided additional vesting conditions linked to the Company’s total shareholder return which the Company will determine every year during the vesting period. The implementation of these market conditions did not materially impact total compensation expense expected to be recognized. The modified portion of the options will vest in whole or in part only if the Company’s total shareholder return achieves specified targets, subject to vesting upon death, disability, qualifying retirement or a change of control. As of June 30, 2011, none of the Company’s executives had met conditions to elect a qualifying retirement.

Restricted Share Awards

As of June 30, 2011, 808,763 restricted shares were outstanding under the 1997 Plan and vest over three to seven years from the initial grant date. The remaining compensation expense to be recognized at June 30, 2011 was approximately $5.1 million. That expense is expected to be recognized over a weighted average remaining vesting period of 1.6 years. The Company recognized compensation expense related to outstanding restricted shares of $0.8 million and $1.6 million during the three and six-months ended June 30, 2011, of which $0.1 million and $0.3 million, respectively, were capitalized as part of the Company’s review of employee salaries eligible for capitalization. The Company recognized compensation expense related to outstanding restricted shares of $1.0 million and $1.8 million during the three and six-months ended June 30, 2010, of which $0.2 million and $0.4 million, respectively, were capitalized. The expensed amounts are included in general and administrative expense on the Company’s consolidated statement of operations in the respective periods.

The following table summarizes the Company’s restricted share activity for the six-months ended June 30, 2011:


				Weighted
				Average Grant
	Shares			Date Fair value
Non-vested at January 1, 2011		851,278		$	10.75
Granted		197,035			11.92
Vested		(237,541	)		19.76
Forfeited		(2,009	)		15.04

Non-vested at June 30, 2011		808,763		$	9.47

On March 2, 2011, the Compensation Committee of the Company’s Board of Trustees awarded 174,012 restricted shares to the Company’s executives. The restricted shares will cliff vest after three years from the grant date. The vesting of the restricted shares is also subject to acceleration upon a change in control or if the recipient of the award were to die, become disabled, be terminated without cause or retire in a qualifying retirement prior to the vesting date. Qualifying retirement for restricted shares granted on March 2, 2011 as provided in the award agreements Plan means the recipient’s voluntary termination of employment after reaching age 57 and accumulating at least 15 years of service with the Company. As of June 30, 2011, none of the Company’s executives had met conditions to elect a qualifying retirement.

Restricted Performance Share Units Plan

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

If the total shareholder return during the measurement period places the Company at or above a certain percentile as compared to its peers based on an industry-based index at the end of the measurement period then the number of shares that will be delivered shall equal a certain percentage (not to exceed 200%) of the participant’s base units.

On the date of each grant, the awards were valued using a Monte Carlo simulation. The fair values of the 2011 and 2010 awards on the grant dates were $2.0 million, respectively, while the 2009 award was $1.1 million. The fair values of each award are being amortized over the three year cliff vesting period. In the case of the 2011 award, the vesting of the RPSUs is also subject to acceleration upon a change in control or if the recipient of the award were to die, become disabled, terminated without cause or retire in a qualifying retirement prior to the vesting date. Qualifying retirement for restricted shares granted on March 2, 2011 as provided under the 1997 Plan means the recipient’s voluntary termination of employment after reaching age 57 and accumulating at least 15 years of service with the Company. As of June 30, 2011, none of the Company’s executives has met conditions to elect a qualifying retirement.

For the three and six-month periods ended June 30, 2011, the Company recognized total compensation expense for the 2011, 2010 and 2009 awards of $0.5 million and $0.8 million, of which $0.1 million and $0.2 million were capitalized as part of the Company’s review of employee salaries eligible for capitalization. For the three and six months ended June 30, 2010, the Company recognized total compensation expense for 2010 and 2009 awards of $0.3 million and $0.5 million, respectively, related to this plan of which nominal amounts were capitalized.

Outperformance Program

On August 28, 2006, the Compensation Committee of the Parent Company’s Board of Trustees adopted a long-term incentive compensation program (the “outperformance program”) under the 1997 Plan. The outperformance program provided for share-based awards, with share issuances (if any), to take the form of both vested and restricted common shares and with any share issuances contingent upon the Company’s total shareholder return during a three year measurement period exceeding specified performance hurdles. These hurdles were not met and, accordingly, no shares were delivered under the outperformance program and the outperformance program has terminated in accordance with its terms. The awards under the outperformance program were accounted for in accordance with the accounting standard for stock-based compensation. The aggregate grant date fair value of the awards under the outperformance program, as adjusted for estimated forfeitures, was 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 each of the three and six-month periods ended June 30, 2011, the Company recognized $0.1 million of compensation expenses related to the outperformance program. For the three and six-month periods ended June 30, 2010, the Company recognized $0.1 million and $0.2 million, respectively, of compensation expenses related to the outperformance program.

Employee Share Purchase Plan

On May 9, 2007, the Parent Company’s shareholders approved the 2007 Non-Qualified Employee Share Purchase Plan (the “ESPP”). The ESPP is intended to provide eligible employees with a convenient means to purchase common shares of the Parent Company through payroll deductions and voluntary cash purchases at an amount equal to 85% of the average closing price per share for a specified period. Under the plan document, the maximum participant contribution for the 2011 plan year is limited to the lesser of 20% of compensation or $50,000. The number of shares initially reserved for issuance under the ESPP is 1.25 million. During the three and six-month periods ended June 30, 2011, employees made purchases under the ESPP of $0.1 million and $0.2 million, respectively. The Company recognized a nominal amount and $0.1 million of compensation expense related to the ESPP during the three and six—month periods ended June 30, 2011, respectively. During the three and six-month periods ended June 30, 2010, employees made purchases under the ESPP of $0.2 million and $0.3 million, respectively. The Company recognized $0.1 million and $0.2 million of compensation expense related to the ESPP during the three and six-month periods ended June 30, 2010, respectively. The Board of Trustees of the Parent Company may terminate the ESPP at its sole discretion at any time.

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 participant-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 six-month periods ended June 30, 2011 and 2010, the Company recorded a net increase in compensation costs of $0.4 million and a net decrease in compensation costs of $0.2 million, respectively, in connection with the Plan due to the change in the market value of the participant investments in the Plan.

The deferred compensation obligations are unfunded, but the Company has purchased company-owned life insurance policies and mutual funds, which can be utilized as a 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 six-month periods ended June 30, 2011 and 2010, the Company recorded a net decrease in compensation costs of $0.4 million and a net increase in compensation costs of $0.2 million, respectively, in connection with the investments in the company-owned policies and mutual funds.

Participants in the Plan may elect to have all or a portion of their deferred compensation invested in the Company’s common shares. The Company holds these shares in a rabbi trust, which is subject to the claims of the Company’s creditors in the event of the Company’s bankruptcy or insolvency. The Plan does not permit diversification of a participant’s deferral allocated to the Company common share and deferrals allocated to Company common shares 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 the 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 June 30, 2011 and 2010, 0.3 million of such shares, respectively, were included in total shares outstanding. Subsequent changes in the fair value of the common shares are not reflected in operations or shareholders’ equity of the Company.

Tax Credit Transactions	6 Months Ended
Tax Credit Transactions	Jun. 30, 2011
Tax Credit Transactions [Abstract]
TAX CREDIT TRANSACTIONS	15. 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 amount of approximately $3.0 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 June 30, 2011 and December 31, 2010, respectively, 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 $2.2 million and $2.1 million at June 30, 2011 and December 31, 2010, respectively. The Company anticipates that once a year beginning in September 2011 through September 2015 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 within 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 cost at June 30, 2011 and December 31, 2010 is $4.3 million, and is included in other assets in 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 $0.3 million and $0.7 million for the three- and six-months ended June 30, 2011, respectively, and $0.3 million and $0.4 million for the three- and six-months ended June 30, 2010, respectively. New Markets Tax Credit Transaction On December 30, 2008, the Company entered into a transaction with USB related to the Cira South Garage in Philadelphia, Pennsylvania and expects to receive a net benefit of $7.8 million under a qualified New Markets Tax Credit Program (“NMTC”). The NMTC was provided for in the Community Renewal Tax Relief Act of 2000 (the “Act”) and is intended to induce investment capital in underserved and impoverished areas of the United States. The Act permits taxpayers (whether companies or individuals) to claim credits against their Federal income taxes for up to 39% of qualified investments in qualified, active low-income businesses or ventures. USB contributed $13.3 million into the development of the Cira South Garage and as such it is entitled to substantially all of the benefits derived from the tax credit, but it does not have a material interest in the underlying economics of the Cira South Garage. This transaction also includes a put/call provision whereby the Company may be obligated or entitled to repurchase USB’s interest. The Company believes the put will be exercised and an amount attributed to that obligation is included in other liabilities and is being accreted to the expected fixed put price. The said put price is insignificant. Based on the contractual arrangements that obligate the Company to deliver tax benefits and provide various other guarantees to USB, the Company concluded that the investment entities established to facilitate the NMTC transaction should be consolidated. The USB contribution of $13.3 million is included in deferred income on the Company’s consolidated balance sheets at June 30, 2011 and December 31, 2010. The USB contribution other than the amount allocated to the put obligation will be recognized as income in the consolidated financial statements when the tax benefits are delivered without risk of recapture to the tax credit investors and the Company’s obligation is relieved. The Company anticipates that it will recognize the net cash received as revenue within other income/expense in the year ended December 31, 2015. The NMTC is subject to 100% recapture for a period of seven years as provided in the Internal Revenue Code. The Company expects that the put/call provision will be exercised in December 2015 when the recapture period ends. Direct and incremental costs incurred in structuring the transaction are deferred and will be recognized as expense in the consolidated financial statements upon the recognition of the related revenue as discussed above. The deferred cost at June 30, 2011 and December 31, 2010 is $5.3 million and is included in other assets in the Company’s consolidated balance sheet.

Segment Information

6 Months Ended

Jun. 30, 2011

Segment Information [Abstract]

SEGMENT INFORMATION

16. SEGMENT INFORMATION

As of June 30, 2011, the Company was managing its portfolio within seven segments: (1) Pennsylvania, (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 segment includes properties in Chester, Delaware, and Montgomery counties in the Philadelphia suburbs. The Philadelphia CBD segment includes properties located in the City of Philadelphia in 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 in the third quarter of 2010. 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 prior period results have been restated to conform to the current period presentation.

Segment information is as follows (in thousands):


	Pennsylvania		Philadelphia				New Jersey		Richmond,
	Suburbs		CBD		Metropolitan, D.C.		/Delaware		Virginia		Austin, Texas		California		Corporate			Total
As of June 30, 2011:
Real estate investments, at cost:
Operating properties	$	1,210,274	$	928,880	$	1,366,282	$	568,992	$	306,243	$	254,920	$	249,450	$	—		$	4,885,041
Construction-in-progress		—		—		—		—		—		—		—		33,314			33,314
Land inventory		—		—		—		—		—		—		—		120,245			120,245

As of December 31, 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

For the three-months ended June 30, 2011:
Total revenue	$	39,137	$	30,573	$	32,616	$	21,098	$	9,277	$	7,637	$	5,382	$	(313	)	$	145,407
Property operating expenses, real estate taxes and third party management expenses		13,572		11,220		12,190		10,004		3,623		3,420		2,821		(275	)		56,575

Net operating income	$	25,565	$	19,353	$	20,426	$	11,094	$	5,654	$	4,217	$	2,561	$	(38	)	$	88,832


For the three-months ended June 30, 2010:
Total revenue	$	37,332	$	18,412	$	34,661	$	22,647	$	8,769	$	7,966	$	5,967	$	(257	)	$	135,497
Property operating expenses, real estate taxes and third party management expenses		12,866		7,956		11,996		10,543		3,165		3,441		2,956		(29	)		52,894

Net operating income	$	24,466	$	10,456	$	22,665	$	12,104	$	5,604	$	4,525	$	3,011	$	(228	)	$	82,603


For the six-months ended June 30, 2011:
Total revenue	$	79,431	$	62,423	$	65,258	$	42,429	$	18,076	$	15,750	$	10,791	$	(547	)	$	293,611
Property operating expenses, real estate taxes and third party management expenses		30,366		23,439		24,514		21,751		7,011		6,514		5,515		(609	)		118,501

Net operating income	$	49,065	$	38,984	$	40,744	$	20,678	$	11,065	$	9,236	$	5,276	$	62		$	175,110


For the six-months ended June 30, 2010:
Total revenue	$	76,814	$	36,962	$	69,403	$	47,940	$	18,168	$	15,965	$	11,871	$	(626	)	$	276,497
Property operating expenses, real estate taxes and third party management expenses		29,622		15,793		24,370		22,787		6,824		6,762		5,684		(480	)		111,362

Net operating income	$	47,192	$	21,169	$	45,033	$	25,153	$	11,344	$	9,203	$	6,187	$	(146	)	$	165,135

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


	Three-month periods						Six-month periods
	ended June 30,						ended June 30,
	2011			2010			2011			2010
	(amounts in thousands)						(amounts in thousands)
Consolidated net operating income	$	88,832		$	82,603		$	175,110		$	165,135
Less:
Interest expense		(34,738	)		(31,210	)		(67,131	)		(62,734	)
Deferred financing costs		(1,070	)		(862	)		(1,998	)		(1,873	)
Depreciation and amortization		(58,014	)		(51,289	)		(109,688	)		(103,318	)
Administrative expenses		(5,890	)		(6,653	)		(12,134	)		(12,745	)
Plus:
Interest income		421			963			862			1,828
Equity in income of real estate ventures		1,088			1,025			2,321			2,321
Net gain on sales of interests in real estate		—			—			2,791			—
Loss on early extinguishment of debt		(756	)		(445	)		(756	)		(1,637	)

Loss from continuing operations		(10,127	)		(5,868	)		(10,623	)		(13,023	)
Income from discontinued operations		3,893			268			3,899			7,024

Net loss	$	(6,234	)	$	(5,600	)	$	(6,724	)	$	(5,999	)

Commitments and Contingencies

6 Months Ended

Jun. 30, 2011

Commitments and Contingencies [Abstract]

COMMITMENTS AND CONTINGENCIES

17. 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.

Environmental

As an owner of real estate, the Company is subject to various environmental laws of federal, state, and local governments. The Company’s compliance with existing laws has not had a material adverse effect on its financial condition and results of operations, and the Company does not believe it will have a material adverse effect in the future. However, the Company cannot predict the impact of unforeseen environmental contingencies or new or changed laws or regulations on its current Properties or on properties that the Company may acquire.

Ground Rent

Future minimum rental payments under the terms of all non-cancellable ground leases under which the Company is the lessee are expensed on a straight-line basis regardless of when payments are due. The Company’s ground leases have remaining lease terms ranging from 18 to 92 years. Minimum future rental payments on non-cancelable leases at June 30, 2011 are as follows (in thousands):


2011 (six months remaining)	$	909
2012		1,818
2013		1,818
2014		1,909
2015		1,909
Thereafter		289,897

One of the land leases for a property 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 is scheduled to 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 Company acquired its rights under the lease (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 or determinable.

Other Commitments or Contingencies

As part of the Company’s September 2004 acquisition of a portfolio of properties from The Rubenstein Company (which the Company refers to as the TRC acquisition), the Company acquired its interest in Two Logan Square, a 708,844 square foot office building in Philadelphia, primarily through its ownership of a second and third mortgage secured by this property. This property is consolidated as the borrower is a variable interest entity and the Company, through its ownership of the second and third mortgages, is the primary beneficiary. The Company currently does not expect to take title to Two Logan Square until, at the earliest, September 2019. If the Company takes fee title to Two Logan Square upon a foreclosure of its mortgage, the Company has agreed to pay an unaffiliated third party that holds a residual interest in the fee owner of this property an amount equal to $2.9 million. On the TRC acquisition date, the Company recorded a liability of $0.7 million and this amount will accrete up to $2.9 million through September 2019. As of June 30, 2011, the Company had a balance of $1.3 million for this liability in its consolidated balance sheet.

The Company is currently being 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 has appealed the proposed adjustment. The proposed adjustment, if upheld, would not result in a material tax liability for the Company. However, an adjustment could raise a question as to whether a contributor of partnership interests in the 2004 transaction could assert a claim against the Company under the tax protection agreement entered into as part of the transaction.

As part of the Company’s 2006 merger with Prentiss Properties Trust, the 2004 TRC acquisition and several of our other transactions, the Company agreed not to sell certain of the properties it acquired in transactions that would trigger taxable income to the former owners. In the case of the TRC acquisition, the Company agreed not to sell acquired properties for periods up to 15 years from the date of the TRC acquisition as follows at June 30, 2011: One Rodney Square and 130/150/170 Radnor Financial Center (January 2015); and One Logan Square, Two Logan Square and Radnor Corporate Center (January 2020). In the Prentiss acquisition, the Company assumed the obligation of Prentiss not to sell Concord Airport Plaza before March 2018. The Company’s agreements generally provide that it may dispose of the subject properties only in transactions that qualify as tax-free exchanges under Section 1031 of the Internal Revenue Code or in other tax deferred transactions. If the Company were to sell a restricted property before expiration of the restricted period in a non-exempt transaction, the Company may be required to make significant payments to the parties who sold the applicable property on account of tax liabilities attributed to them.

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

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

During 2008, in connection with the development of the IRS Philadelphia Campus and the Cira South Garage, the Company entered into a historic tax credit and a new market tax credit arrangement, 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 Events	6 Months Ended
Subsequent Events	Jun. 30, 2011
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	18. SUBSEQUENT EVENTS On July 11, 2011, the Company used available corporate funds and a draw on its Credit Facility to prepay its One Logan Square mortgage debt amounting to $60.0 million without penalty. The Company will also write off $0.8 million of deferred financing costs in the next quarter as a result of this prepayment. The Company has evaluated subsequent events through the date the financial statements were issued.

Summary of Significant Policies (Policies)

6 Months Ended

Jun. 30, 2011

Summary of Significant Policies (Policies) [Abstract]

Basis of Presentation

Reclassifications and Out of Period Adjustment

Principles of Consolidation

Use of Estimates

Operating Properties

Purchase Price Allocation

Impairment or Disposal of Long-Lived Assets

During the Company’s impairment review for the six month periods ended June 30, 2011 and 2010, the Company determined that no impairment charges were necessary.

Investments in Unconsolidated Real Estate Ventures

Revenue Recognition

Stock-Based Compensation Plans

Accounting for Derivative Instruments and Hedging Activities

Fair Value Measurements

•

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

•

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

•

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

Income Taxes

Parent Company

Operating Partnership

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

Recent Accounting Pronouncement

Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2011

Summary of Significant Accounting Policies (Tables) [Abstract]

Fair value of assets and liabilities on recurring basis

Fair Value Measurements at Reporting

Date Using:

Quoted Prices in

Active Markets for

Significant Other

Unobservable

June 30,

Identical Assets

Observable Inputs

Inputs

Description

2011

(Level 1)

(Level 2)

(Level 3)

Recurring

Assets:

Available-for-Sale Securities

284

—

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

—

Real Estate Investments (Tables)

6 Months Ended

Jun. 30, 2011

Real Estate Investments (Tables) [Abstract]

Gross carrying value of rental properties


	June 30, 2011		December 31, 2010

Land	$	698,982	$	697,724
Building and improvements		3,722,243		3,693,579
Tenant improvements		463,816		442,808

	$	4,885,041	$	4,834,111

Business Acquisition, Purchase Price Allocation


	August 5,
	2010

Building and tenant improvements	$	98,188
Intangible assets acquired		28,856
Below market lease liabilities assumed		(683	)

Total	$	126,361

Schedule of Intangibles assets and liabilities acquired


			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

Supplemental pro forma operating data


	Three-months			Six-months
	ended June 30, 2010			ended June 30, 2010

Pro forma revenues	$	142,426		$	290,467
Pro forma loss from continuing operations		(5,615	)		(12,429	)
Pro forma net loss attributable to common shareholders		(7,314	)		(9,448	)

Loss per common share from continuing operations:
Basic — as reported	$	(0.06	)	$	(0.13	)

Basic — as pro forma	$	(0.06	)	$	(0.13	)


Diulted — as reported	$	(0.06	)	$	(0.13	)

Diulted — as pro forma	$	(0.06	)	$	(0.13	)


Loss per common share:
Basic — as reported	$	(0.06	)	$	(0.08	)

Basic — as pro forma	$	(0.06	)	$	(0.08	)


Diulted — as reported	$	(0.06	)	$	(0.08	)

Diulted — as pro forma	$	(0.06	)	$	(0.08	)

Investment in Unconsolidated Ventures (Tables)

6 Months Ended

Jun. 30, 2011

Investment in Unconsolidated Ventures (Tables) [Abstract]

Financial position of unconsolidated Real Estate Ventures


	June 30,		December 31,
	2011		2010

Net property	$	726,254	$	804,705
Other assets		99,589		105,576
Other liabilities		39,583		44,509
Debt		683,679		748,387
Equity		102,581		117,385
Company’s share of equity (Company’s basis)		82,927		84,372

Summary of results of operations of unconsolidated Real Estate Ventures


	Three-month periods					Six-month periods
	ended June 30,					ended June 30,
	2011			2010		2011			2010

Revenue	$	32,722		$	30,528	$	72,398		$	54,598
Operating expenses		14,370			10,305		30,544			19,001
Interest expense, net		9,550			9,270		21,673			17,008
Depreciation and amortization		8,487			8,302		18,968			14,524
Net (loss) income		(315	)		2,651		(1,213	)		4,065
Company’s share of income (Company’s basis)		1,088			1,025		2,321			2,321

Deferred Costs (Tables)	6 Months Ended
Deferred Costs (Tables)	Jun. 30, 2011
Deferred Costs (Tables) [Abstract]
Deferred Costs	<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" --> <!-- Begin Block Tagged Note Table: bdn-20110630_note5_table1 - bdn:ComponentsOfDeferredCostsNetTextBlock--> <div align="justify" style="font-size: 10pt; font-family: 'Times New Roman',Times,serif"> <div style="font-family: 'Times New Roman',Times,serif; margin-left: 0in; "> <div align="center"> <table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%"> <!-- Begin Table Head --> <tr valign="bottom"> <td width="58%"> </td> <td width="3%"> </td> <td width="1%"> </td> <td width="9%"> </td> <td width="1%"> </td> <td width="3%"> </td> <td width="1%"> </td> <td width="9%"> </td> <td width="1%"> </td> <td width="3%"> </td> <td width="1%"> </td> <td width="9%"> </td> <td width="1%"> </td> </tr> <tr style="font-size: 10pt" valign="bottom"> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="10" style="border-bottom: 1px solid #000000">June 30, 2011</td> <td> </td> </tr> <tr style="font-size: 10pt" valign="bottom"> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="2">Accumulated</td> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="2">Deferred Costs,</td> <td> </td> </tr> <tr style="font-size: 10pt" valign="bottom"> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000">Total Cost</td> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000">Amortization</td> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000">net</td> <td> </td> </tr> <!-- End Table Head --> <!-- Begin Table Body --> <tr valign="bottom"><!-- Blank Space --> <td> <div style="margin-left:15px; text-indent:-15px"> </div></td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> </tr> <tr valign="bottom" style="background: #cceeff"> <td> <div style="margin-left:15px; text-indent:-15px">Leasing Costs </div></td> <td> </td> <td align="left">$</td> <td align="right">133,734</td> <td> </td> <td> </td> <td nowrap="nowrap" align="left">$</td> <td align="right">(48,223</td> <td nowrap="nowrap">)</td> <td> </td> <td align="left">$</td> <td align="right">85,511</td> <td> </td> </tr> <tr valign="bottom"> <td> <div style="margin-left:15px; text-indent:-15px">Financing Costs </div></td> <td> </td> <td> </td> <td align="right">39,605</td> <td> </td> <td> </td> <td nowrap="nowrap" align="left"> </td> <td align="right">(11,618</td> <td nowrap="nowrap">)</td> <td> </td> <td> </td> <td align="right">27,987</td> <td> </td> </tr> <tr style="font-size: 1px"> <td> <div style="margin-left:15px; text-indent:-15px"> </div></td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td> <td> </td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td> <td> </td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td> <td> </td> </tr> <tr valign="bottom" style="background: #cceeff"> <td> <div style="margin-left:30px; text-indent:-15px">Total </div></td> <td> </td> <td align="left">$</td> <td align="right">173,339</td> <td> </td> <td> </td> <td nowrap="nowrap" align="left">$</td> <td align="right">(59,841</td> <td nowrap="nowrap">)</td> <td> </td> <td align="left">$</td> <td align="right">113,498</td> <td> </td> </tr> <tr style="font-size: 1px"> <td> <div style="margin-left:15px; text-indent:-15px"> </div></td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td> <td> </td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td> <td> </td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td> <td> </td> </tr> <!-- End Table Body --> </table> </div> <div align="center"> <table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%"> <!-- Begin Table Head --> <tr valign="bottom"> <td width="58%"> </td> <td width="3%"> </td> <td width="1%"> </td> <td width="9%"> </td> <td width="1%"> </td> <td width="3%"> </td> <td width="1%"> </td> <td width="9%"> </td> <td width="1%"> </td> <td width="3%"> </td> <td width="1%"> </td> <td width="9%"> </td> <td width="1%"> </td> </tr> <tr style="font-size: 10pt" valign="bottom"> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="10" style="border-bottom: 1px solid #000000">December 31, 2010</td> <td> </td> </tr> <tr style="font-size: 10pt" valign="bottom"> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="2">Accumulated</td> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="2">Deferred Costs,</td> <td> </td> </tr> <tr style="font-size: 10pt" valign="bottom"> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000">Total Cost</td> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000">Amortization</td> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000">net</td> <td> </td> </tr> <!-- End Table Head --> <!-- Begin Table Body --> <tr valign="bottom"><!-- Blank Space --> <td> <div style="margin-left:15px; text-indent:-15px"> </div></td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> </tr> <tr valign="bottom" style="background: #cceeff"> <td> <div style="margin-left:15px; text-indent:-15px">Leasing Costs </div></td> <td> </td> <td align="left">$</td> <td align="right">123,724</td> <td> </td> <td> </td> <td nowrap="nowrap" align="left">$</td> <td align="right">(43,930</td> <td nowrap="nowrap">)</td> <td> </td> <td align="left">$</td> <td align="right">79,794</td> <td> </td> </tr> <tr valign="bottom"> <td> <div style="margin-left:15px; text-indent:-15px">Financing Costs </div></td> <td> </td> <td> </td> <td align="right">37,257</td> <td> </td> <td> </td> <td nowrap="nowrap" align="left"> </td> <td align="right">(10,934</td> <td nowrap="nowrap">)</td> <td> </td> <td> </td> <td align="right">26,323</td> <td> </td> </tr> <tr style="font-size: 1px"> <td> <div style="margin-left:15px; text-indent:-15px"> </div></td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td> <td> </td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td> <td> </td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td> <td> </td> </tr> <tr valign="bottom" style="background: #cceeff"> <td> <div style="margin-left:30px; text-indent:-15px">Total </div></td> <td> </td> <td align="left">$</td> <td align="right">160,981</td> <td> </td> <td> </td> <td nowrap="nowrap" align="left">$</td> <td align="right">(54,864</td> <td nowrap="nowrap">)</td> <td> </td> <td align="left">$</td> <td align="right">106,117</td> <td> </td> </tr> <tr style="font-size: 1px"> <td> <div style="margin-left:15px; text-indent:-15px"> </div></td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td> <td> </td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td> <td> </td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td> <td> </td> </tr> <!-- End Table Body --> </table> </div> </div> </div>

Intangible Assets (Tables)

6 Months Ended

Jun. 30, 2011

Intangible Assets (Tables) [Abstract]

Intangible assets


	June 30, 2011
			Accumulated			Intangible Assets,
	Total Cost		Amortization			net

In-place lease value	$	97,523	$	(61,390	)	$	36,133
Tenant relationship value		80,242		(46,041	)		34,201
Above market leases acquired		16,718		(8,651	)		8,067

Total	$	194,483	$	(116,082	)	$	78,401


Below market leases acquired	$	66,402	$	(40,846	)	$	25,556


	December 31, 2010
			Accumulated			Intangible Assets,
	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

Annual amortization of intangible assets and liabilities


	Assets		Liabilities
2011 (six months remaining)	$	14,510	$	3,581
2012		20,705		6,447
2013		12,452		5,902
2014		9,481		4,334
2015		6,717		2,158
Thereafter		14,536		3,134

Total	$	78,401	$	25,556

Debt Obligations (Tables)

6 Months Ended

Jun. 30, 2011

Debt Obligations (Tables) [Abstract]

Consolidated debt obligations

MORTGAGE DEBT:


							Effective
	June 30,			December 31,			Interest			Maturity
Property / Location	2011			2010			Rate			Date

Arboretum I, II, III & V	$	—		$	20,386			7.59	% (a)	Jul-11
Midlantic Drive/Lenox Drive/DCC I		—			56,514			8.05	%(b)	Oct-11
Research Office Center		—			39,145			5.30	%(c), (d)	Oct-11
Concord Airport Plaza		33,914			34,494			5.55	%(d)	Jan-12
Newtown Square/Berwyn Park/Libertyview		57,334			58,102			7.25	%	May-13
Southpoint III		2,249			2,597			7.75	%	Apr-14
Tysons Corner		95,698			96,507			5.36	%(d)	Aug-15
Two Logan Square		89,800			89,800			7.57	%	Apr-16
One Logan Square		60,000			60,000			4.50	% (e)	Jul-16
IRS Philadelphia Campus		205,676			208,366			6.95	%	Sep-30
Cira South Garage		45,372			46,335			7.11	%	Sep-30

Principal balance outstanding		590,043			712,246
Plus: unamortized fixed-rate debt premiums (discounts), net		(1,220	)		(457	)

Total mortgage indebtedness	$	588,823		$	711,789


UNSECURED DEBT:
$345.0M 3.875% Guaranteed Exchangeable Notes due 2026		59,835			59,835			5.50	% (f)	Oct-11
Bank Term Loan		183,000			183,000			LIBOR + 0.800	% (g)	Jun-12
Credit Facility		42,000			183,000			LIBOR + 0.725	% (g)	Jun-12
$300.0M 5.750% Guaranteed Notes due 2012		153,694			175,200			5.73	%	Apr-12
$250.0M 5.400% Guaranteed Notes due 2014		242,681			242,681			5.53	%	Nov-14
$250.0M 7.500% Guaranteed Notes due 2015		248,585			250,000			7.77	%	May-15
$250.0M 6.000% Guaranteed Notes due 2016		250,000			250,000			5.95	%	Apr-16
$300.0M 5.700% Guaranteed Notes due 2017		300,000			300,000			5.68	%	May-17
$325.0M 4.950% Guaranteed Notes due 2018		325,000			—			5.14	%	Apr-18
Indenture IA (Preferred Trust I)		27,062			27,062			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		1,883,405			1,722,326
Less: unamortized exchangeable debt discount		(362	)		(906	)
unamortized fixed-rate debt discounts, net		(5,845	)		(2,763	)

Total unsecured indebtedness	$	1,877,198		$	1,718,657


Total Debt Obligations	$	2,466,021		$	2,430,446


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

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

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

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


(e)		This mortgage is subject to an interest rate floor of 4.50% on a monthly basis. On July 11, 2011, the Company prepaid the balance of the loan without penalty (see Note 18).

(f)		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.

(g)		On March 31, 2011, the maturity dates of the Bank Term Loan and the Credit Facility were extended to June 29, 2012 from June 29, 2011. On June 29, 2011, the Company paid a total extension fee amounting to $1.2 million which is equal to 15 basis points of the outstanding principal balance of the Bank Term Loan and of the committed amount under the Credit Facility. The extension of the maturity dates was at the Company’s option under the Bank Term Loan and the Credit Facility agreements. There were no changes in the terms and conditions of the loan agreements as a result of the maturity date extensions.

Summary of debt repurchases


	Repurchase							Deferred Financing
Notes	Amount		Principal		Loss			Amortization
2012 5.750% Notes	$	22,331	$	21,506	$	(821	)	$	82
2015 7.500% Notes		1,600		1,415		(211	)		8

	$	23,931	$	22,921	$	(1,032	)	$	90

Schedule of principal payments of debt obligations


2011	$	6,339
2012		424,630
2013		67,037
2014		255,016
2015		348,742
Thereafter		1,371,684

Total principal payments		2,473,448
Net unamortized premiums/(discounts)		(7,427	)

Outstanding indebtedness	$	2,466,021

Fair Value of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2011

Fair Value of Financial Instruments (Tables) [Abstract]

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


	June 30, 2011					December 31, 2010
	Carrying			Fair		Carrying			Fair
	Amount			Value		Amount			Value

Mortgage payable, net of discounts	$	588,823		$	602,815	$	711,789		$	726,348
Unsecured notes payable, net of discounts	$	1,573,588		$	1,702,493	$	1,274,047		$	1,338,743
Variable rate debt instruments	$	303,610		$	295,131	$	444,610		$	432,556
Notes receivable	$	32,255	(a)	$	29,995	$	31,216	(a)	$	28,921


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

Discontinued Operations (Tables)

6 Months Ended

Jun. 30, 2011

Discontinued Operations (Tables) [Abstract]

Revenue and expense information for the property classified as discontinued operations


	Three-month period		Six-month period
	ended June 30, 2011		ended June 30, 2011
Revenue:
Rents	$	199	$	475
Tenant reimbursements		18		83
Other		—		(78	)

Total revenue		217		480

Expenses:
Property operating expenses		101		260
Real estate taxes		19		70
Depreciation and amortization		40		87

Total operating expenses		160		417

Income from discontinued operations before gain on sale of interests in real estate		57		63

Net gain on disposition of discontinued operations		3,836		3,836

Income from discontinued operations	$	3,893	$	3,899


	Three-month period		Six-month period
	ended June 30, 2010		ended June 30, 2010
Revenue:
Rents	$	1,526	$	2,993
Tenant reimbursements		642		1,357
Other		2		2

Total revenue		2,170		4,352

Expenses:
Property operating expenses		751		1,606
Real estate taxes		315		631
Depreciation and amortization		836		1,440

Total operating expenses		1,902		3,677

Income from discontinued operations before gain on sale of interests in real estate		268		675

Net gain on disposition of discontinued operations		—		6,349

Income from discontinued operations	$	268	$	7,024

Beneficiaries Equity of The Parent Company (Tables)

6 Months Ended

Jun. 30, 2011

Beneficiaries' Equity of The Parent Company (Tables) [Abstract]

Earnings per Share (EPS)


	Three-month periods ended June 30,
	2011						2010
	Basic			Diluted			Basic			Diluted

Numerator
Loss from continuing operations	$	(10,127	)	$	(10,127	)	$	(5,868	)	$	(5,868	)

Net loss from continuing operations attributable to non-controlling interests		243			243			165			165
Amount allocable to unvested restricted shareholders		(121	)		(121	)		(128	)		(128	)
Preferred share dividends		(1,998	)		(1,998	)		(1,998	)		(1,998	)

Loss from continuing operations available to common shareholders		(12,003	)		(12,003	)		(7,829	)		(7,829	)

Income (loss) from discontinued operations		3,893			3,893			268			268
Discontinued operations attributable to non-controlling interests		(78	)		(78	)		(6	)		(6	)

Discontinued operations attributable to common shareholders		3,815			3,815			262			262


Net loss attributable to common shareholders	$	(8,188	)	$	(8,188	)	$	(7,567	)	$	(7,567	)


Denominator
Weighted-average shares outstanding		135,342,538			135,342,538			131,510,924			131,510,924

Earnings per Common Share:
Loss from continuing operations attributable to common shareholders	$	(0.09	)	$	(0.09	)	$	(0.06	)	$	(0.06	)
Discontinued operations attributable to common shareholders		0.03			0.03			—			—

Net loss attributable to common shareholders	$	(0.06	)	$	(0.06	)	$	(0.06	)	$	(0.06	)


	Six-month periods ended June 30,
	2011						2010
	Basic			Diluted			Basic			Diluted

Numerator
Loss from continuing operations	$	(10,623	)	$	(10,623	)	$	(13,023	)	$	(13,023	)

Net loss from continuing operations attributable to non-controlling interests		294			294			360			360
Amount allocable to unvested restricted shareholders		(263	)		(263	)		(256	)		(256	)
Preferred share dividends		(3,996	)		(3,996	)		(3,996	)		(3,996	)

Loss from continuing operations available to common shareholders		(14,588	)		(14,588	)		(16,915	)		(16,915	)

Income (loss) from discontinued operations		3,899			3,899			7,024			7,024
Discontinued operations attributable to non-controlling interests		(78	)		(78	)		(150	)		(150	)

Discontinued operations attributable to common shareholders		3,821			3,821			6,874			6,874


Net loss attributable to common shareholders	$	(10,767	)	$	(10,767	)	$	(10,041	)	$	(10,041	)


Denominator
Weighted-average shares outstanding		134,962,093			134,962,093			130,146,853			130,146,853

Earnings per Common Share:
Loss from continuing operations attributable to common shareholders	$	(0.11	)	$	(0.11	)	$	(0.13	)	$	(0.13	)
Discontinued operations attributable to common shareholders		0.03			0.03			0.05			0.05

Net loss attributable to common shareholders	$	(0.08	)	$	(0.08	)	$	(0.08	)	$	(0.08	)

Partners Equity of The Operating Partnership (Tables)

6 Months Ended

Jun. 30, 2011

Partners Equity of The Operating Partnership (Tables) [Abstract]

Earnings per Common Partnership Unit


	Three-month periods ended June 30,
	2011						2010
	Basic			Diluted			Basic			Diluted

Numerator
Loss from continuing operations	$	(10,127	)	$	(10,127	)	$	(5,868	)	$	(5,868	)

Amount allocable to unvested restricted unitholders		(121	)		(121	)		(128	)		(128	)
Preferred unit dividends		(1,998	)		(1,998	)		(1,998	)		(1,998	)

Loss from continuing operations available to common unitholders		(12,246	)		(12,246	)		(7,994	)		(7,994	)

Discontinued operations attributable to common unitholders		3,893			3,893			268			268


Net loss attributable to common unitholders	$	(8,353	)	$	(8,353	)	$	(7,726	)	$	(7,726	)


Denominator
Weighted-average units outstanding		145,220,764			145,220,764			134,320,032			134,320,032

Earnings per Common Share:
Loss from continuing operations attributable to common unitholders	$	(0.09	)	$	(0.09	)	$	(0.06	)	$	(0.06	)
Discontinued operations attributable to common unitholders		0.03			0.03			—			—

Net loss attributable to common unitholders	$	(0.06	)	$	(0.06	)	$	(0.06	)	$	(0.06	)


	Six-month periods ended June 30,
	2011						2010
	Basic			Diluted			Basic			Diluted

Numerator
Loss from continuing operations	$	(10,623	)	$	(10,623	)	$	(13,023	)	$	(13,023	)

Amount allocable to unvested restricted unitholders		(263	)		(263	)		(256	)		(256	)
Preferred unit dividends		(3,996	)		(3,996	)		(3,996	)		(3,996	)

Loss from continuing operations available to common unitholders		(14,882	)		(14,882	)		(17,275	)		(17,275	)

Discontinued operations attributable to common unitholders		3,899			3,899			7,024			7,024


Net loss attributable to common unitholders	$	(10,983	)	$	(10,983	)	$	(10,251	)	$	(10,251	)


Denominator
Weighted-average units outstanding		144,852,515			144,852,515			132,955,961			132,955,961

Earnings per Common Share:
Loss from continuing operations attributable to common unitholders	$	(0.11	)	$	(0.11	)	$	(0.13	)	$	(0.13	)
Discontinued operations attributable to common unitholders		0.03			0.03			0.05			0.05

Net loss attributable to common unitholders	$	(0.08	)	$	(0.08	)	$	(0.08	)	$	(0.08	)

Share Based and Deferred Compensation (Tables)

6 Months Ended

Jun. 30, 2011

Share Based and Deferred Compensation (Tables) [Abstract]

Option activity


				Weighted		Weighted Average
				Average		Remaining Contractual		Aggregate Intrinsic
	Shares			Exercise Price		Term (in years)		Value
Outstanding at January 1, 2011		3,116,611		$	14.56		7.81	$	(9,080,625	)
Granted		603,241			11.89		9.68		(180,972	)
Exercised		(76,887	)		2.91


Outstanding at June 30, 2011		3,642,965		$	14.37		7.70	$	(10,115,971	)


Vested/Exercisable at June 30, 2011		2,331,021		$	16.75		7.05	$	(11,802,863	)

Company's restricted share activity


				Weighted
				Average Grant
	Shares			Date Fair value
Non-vested at January 1, 2011		851,278		$	10.75
Granted		197,035			11.92
Vested		(237,541	)		19.76
Forfeited		(2,009	)		15.04

Non-vested at June 30, 2011		808,763		$	9.47

Segment Information (Tables)

6 Months Ended

Jun. 30, 2011

Segment Information (Tables) [Abstract]

Segment information


	Pennsylvania		Philadelphia				New Jersey		Richmond,
	Suburbs		CBD		Metropolitan, D.C.		/Delaware		Virginia		Austin, Texas		California		Corporate			Total
As of June 30, 2011:
Real estate investments, at cost:
Operating properties	$	1,210,274	$	928,880	$	1,366,282	$	568,992	$	306,243	$	254,920	$	249,450	$	—		$	4,885,041
Construction-in-progress		—		—		—		—		—		—		—		33,314			33,314
Land inventory		—		—		—		—		—		—		—		120,245			120,245

As of December 31, 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

For the three-months ended June 30, 2011:
Total revenue	$	39,137	$	30,573	$	32,616	$	21,098	$	9,277	$	7,637	$	5,382	$	(313	)	$	145,407
Property operating expenses, real estate taxes and third party management expenses		13,572		11,220		12,190		10,004		3,623		3,420		2,821		(275	)		56,575

Net operating income	$	25,565	$	19,353	$	20,426	$	11,094	$	5,654	$	4,217	$	2,561	$	(38	)	$	88,832


For the three-months ended June 30, 2010:
Total revenue	$	37,332	$	18,412	$	34,661	$	22,647	$	8,769	$	7,966	$	5,967	$	(257	)	$	135,497
Property operating expenses, real estate taxes and third party management expenses		12,866		7,956		11,996		10,543		3,165		3,441		2,956		(29	)		52,894

Net operating income	$	24,466	$	10,456	$	22,665	$	12,104	$	5,604	$	4,525	$	3,011	$	(228	)	$	82,603


For the six-months ended June 30, 2011:
Total revenue	$	79,431	$	62,423	$	65,258	$	42,429	$	18,076	$	15,750	$	10,791	$	(547	)	$	293,611
Property operating expenses, real estate taxes and third party management expenses		30,366		23,439		24,514		21,751		7,011		6,514		5,515		(609	)		118,501

Net operating income	$	49,065	$	38,984	$	40,744	$	20,678	$	11,065	$	9,236	$	5,276	$	62		$	175,110


For the six-months ended June 30, 2010:
Total revenue	$	76,814	$	36,962	$	69,403	$	47,940	$	18,168	$	15,965	$	11,871	$	(626	)	$	276,497
Property operating expenses, real estate taxes and third party management expenses		29,622		15,793		24,370		22,787		6,824		6,762		5,684		(480	)		111,362

Net operating income	$	47,192	$	21,169	$	45,033	$	25,153	$	11,344	$	9,203	$	6,187	$	(146	)	$	165,135

Reconciliation of consolidated net operating income


	Three-month periods						Six-month periods
	ended June 30,						ended June 30,
	2011			2010			2011			2010
	(amounts in thousands)						(amounts in thousands)
Consolidated net operating income	$	88,832		$	82,603		$	175,110		$	165,135
Less:
Interest expense		(34,738	)		(31,210	)		(67,131	)		(62,734	)
Deferred financing costs		(1,070	)		(862	)		(1,998	)		(1,873	)
Depreciation and amortization		(58,014	)		(51,289	)		(109,688	)		(103,318	)
Administrative expenses		(5,890	)		(6,653	)		(12,134	)		(12,745	)
Plus:
Interest income		421			963			862			1,828
Equity in income of real estate ventures		1,088			1,025			2,321			2,321
Net gain on sales of interests in real estate		—			—			2,791			—
Loss on early extinguishment of debt		(756	)		(445	)		(756	)		(1,637	)

Loss from continuing operations		(10,127	)		(5,868	)		(10,623	)		(13,023	)
Income from discontinued operations		3,893			268			3,899			7,024

Net loss	$	(6,234	)	$	(5,600	)	$	(6,724	)	$	(5,999	)

Commitments and Contingencies (Tables)

6 Months Ended

Jun. 30, 2011

Commitments and Contingencies (Tables) [Abstract]

Operating Leases Future Minimum Payments Due


2011 (six months remaining)	$	909
2012		1,818
2013		1,818
2014		1,909
2015		1,909
Thereafter		289,897

Organization of The Parent Company and The Operating Partnership (Details) sqft in Millions	Jun. 30, 2011 sqft
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Ownership in the Operating Partnership	93.20%
Parent Company [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Net rentable square feet	25.7
Unconsolidated real estate ventures [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Number of unconsolidated real estate ventures	16
Net rentable square feet	6,100,000
Wholly-owned management company subsidiaries [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Net rentable square feet	33.7
Third Parties and Unconsolidated Real Estate Ventures [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Net rentable square feet	8.0
Office Properties [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Total number of properties owned	209
Industrial facilities [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Total number of properties owned	20
Mixed-use properties [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Total number of properties owned	6
Mixed-use properties [Member] \| Unconsolidated real estate ventures [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Net rentable square feet	25,700,000

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Jun. 30, 2011	Dec. 31, 2010
Assets:
Available-for-Sale Securities	$ 284	$ 248
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets:
Available-for-Sale Securities	284	248
Significant Other Observable Inputs (Level 2) [Member]
Assets:
Available-for-Sale Securities	0	0
Unobservable Inputs (Level 3)[Member]
Assets:
Available-for-Sale Securities	$ 0	$ 0

Summary of Significant Accounting Policies (Details Textuals) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Dec. 31, 2006
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Depreciation and amortization expense relating to intangibles	$ 4.7
PJP VII [Member]
Organization of The Parent Company and The Operating Partnership (Textuals) [Abstract]
Payment guarantees other than the guarantee	0.7	$ 0.7
Restatement Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Depreciation and amortization expense relating to intangibles	$ 4.7	$ 4.7	$ 1.7	$ 1.4	$ 1.8	$ 1.7	$ 1.5

Summary of Significant Accounting Policies (Details Textuals 1) - USD ($) $ in Millions	1 Months Ended	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2009	Dec. 31, 2008	Jun. 02, 2010
Summary of Significant Accounting Policies (Textuals) [Abstract]
Leasing cost reclassified to capital expenditure						$ 14.0
Prior period depreciation and Amortization adjustment		$ 4.7
Development expense for land	$ 7.7	7.7			$ 7.7
Revenue increased by straight-line rent adjustment		4.1		$ 1.8	8.3	3.8
Increased revenue due to amortization of deferred rent		0.6		0.7	1.2	1.6
Decrease in revenue due to amortization of lease incentives		$ 0.4		0.3	$ 0.6	1.0
Increase in Common shares available for future awards									6,000,000
Increase in shares due to amendments in plan, shares solely available for options and share appreciation rights									3,600,000
Common shares available for future awards	5,787,730	5,787,730			5,787,730
Common shares available for options and stock appreciation rights	4,550,724	4,550,724			4,550,724
Options awarded, term	one to ten-year
Stock-based compensation expense		$ 1.6		1.8	$ 3.3	3.1
Stock-based compensation expense, capitalized		$ 0.4		$ 0.4	$ 0.7	$ 0.6
Additional income related to electricity charges			$ 0.5
Overstatement of revenue due to under billing			$ 0.5
Understatement of Revenue							$ 0.3	$ 0.2

Real Estate Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2011	Dec. 31, 2010
Gross carrying value of rental properties
Land	$ 698,982	$ 697,724
Building and improvements	3,722,243	3,693,579
Tenant improvements	463,816	442,808
Rental properties	$ 4,885,041	$ 4,834,111

Real Estate Investments (Details 1) - Three Logan Square [Member] $ in Thousands	Aug. 05, 2010 USD ($)
Purchase price of allocation
Building and tenant improvements	$ 98,188
Intangible assets acquired	28,856
Below market lease liabilities assumed	(683)
Total	$ 126,361

Real Estate Investments (Details 2) - Three Logan Square [Member] $ in Thousands	6 Months Ended
	Jun. 30, 2011	Aug. 05, 2010 USD ($)
Intangible assets
Intangible assets acquired		$ 28,856
Weighted Average Amortization Period (in years)	23
Intangible liabilities:
Below market leases assumed		683
Weighted Average Amortization Period (in years)	1
Leases, Acquired-in-Place [Member]
Intangible assets
Intangible assets acquired		13,584
Weighted Average Amortization Period (in years)	3
Customer Relationships [Member]
Intangible assets
Intangible assets acquired		8,870
Weighted Average Amortization Period (in years)	5
Above market tenant leases acquired [Member]
Intangible assets
Intangible assets acquired		895
Weighted Average Amortization Period (in years)	1
Below market ground lease acquired [Member]
Intangible assets
Intangible assets acquired		5,507
Weighted Average Amortization Period (in years)	82
Intangible liabilities:
Below market leases assumed		$ 683

Real Estate Investments (Details 3) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Supplemental pro forma operating data
Pro forma revenues		$ 142,426		$ 290,467
Pro forma loss from continuing operations		(5,615)		(12,429)
Pro forma net loss available to common shareholders		$ (7,314)		$ (9,448)
Loss per common share from continuing operations :
Loss from continuing operations attributable to common shareholders, Basic	$ (0.09)	$ (0.06)	$ (0.11)	$ (0.13)
Basic -- as pro forma		(0.06)		(0.13)
Loss from continuing operations attributable to common shareholders, Diluted	(0.09)	(0.06)	(0.11)	(0.13)
Diluted - as pro forma		0.06		(0.13)
Loss per common share:
Basic -- as reported	(0.06)	(0.06)	(0.08)	(0.08)
Basic -- as pro forma		(0.06)		(0.08)
Diluted - as reported	$ (0.06)	(0.06)	$ (0.08)	(0.08)
Diluted - as pro forma		$ (0.06)		$ (0.08)

Real Estate Investments (Details Textuals)	Jun. 30, 2011 USD ($)	Mar. 28, 2011 USD ($) sqft	Jan. 20, 2011 USD ($)	Aug. 05, 2010 USD ($) sqft
Real Estate Investments (Textuals)
Assumed security deposits obligations	$ 700,000
Overlook I And II [Member]
Real Estate Investments (Textuals)
Net rentable space of property acquired \| sqft		126,496
Advance under credit facility		$ 600,000,000
Lease percentage of acquired property		100.00%
Acquired real estate, cost of property		$ 12,600,000
Parcel of land in PA [Member]
Real Estate Investments (Textuals)
Acquisition related costs			$ 500,000
Business Acquisition, consideration received			4,900,000
Acquired real estate, cost of property			$ 9,300,000
Parcel of land in PA [Member] \| Partnership Interest [Member]
Real Estate Investments (Textuals)
Business Acquisition, Equity Interest Issued or Issuable, Description			50% limited interest in the partnership
Three Logan Square [Member]
Real Estate Investments (Textuals)
Net rentable space of property acquired \| sqft				1,000,000
Recognized tenant and other receivables from acquisition				$ 1,100,000
Prepaid real estate taxes from acquisition				1,500,000
Acquisition related costs				$ 400,000
Number of storey of office tower acquired				53
Lease percentage of acquired property				67.20%
Acquisitions through cash				$ 51,200,000
Assumed security deposits obligations				900,000
Closing market price of Parent Company's common shares on acquisition date				11.54
Annual dividend rate per share				0.60
Net amount of cash paid after assumed liabilities				50,300,000
Acquired real estate, cost of property				$ 129,000,000
Three Logan Square [Member] \| Partnership Interest [Member]
Real Estate Investments (Textuals)
Business Acquisition, Equity Interest Issued or Issuable, Number of Units				7,111,112

Real Estate Investments (Details Textuals 1) $ in Millions	6 Months Ended
Real Estate Investments (Details Textuals 1) $ in Millions	Jun. 30, 2011 USD ($)	Jul. 29, 2011 USD ($) sqft	Jun. 27, 2011 USD ($) sqft
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net rentable square feet of properties sold \| sqft		347,620
Sales price of properties sold		$ 86.7
Gain on sale of ownership interest	$ 2.8
Remaining Ownership Interest in Real Estate Properties	11.00%
Number of properties with ownership interest	3
Three Greentree Center [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net rentable square feet of properties sold \| sqft			69,300
Sales price of properties sold			$ 5.9
Lease percentage of sold property			13.90%

Investment in Unconsolidated Ventures (Details) - USD ($) $ in Thousands	Jun. 30, 2011	Dec. 31, 2010
Financial position of the Real Estate Ventures
Company's share of equity (Company's basis)	$ 82,927	$ 84,372
Unconsolidated real estate ventures [Member]
Financial position of the Real Estate Ventures
Net property	726,254	804,705
Other Assets	99,589	105,576
Other Liabilities	39,583	44,509
Debt	683,679	748,387
Equity	102,581	117,385
Company's share of equity (Company's basis)	$ 82,927	$ 84,372

Investment in Unconsolidated Ventures (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Summary of results of operations of Real Estate Ventures
Company's share of income (Company's basis)	$ 1,088	$ 1,025	$ 2,321	$ 2,321
Unconsolidated real estate ventures [Member]
Summary of results of operations of Real Estate Ventures
Revenue	32,722	30,528	72,398	54,598
Operating expenses	14,370	10,305	30,544	19,001
Interest expense, net	9,550	9,270	21,673	17,008
Depreciation and amortization	8,487	8,302	18,968	14,524
Net (loss) income	(315)	2,651	(1,213)	4,065
Company's share of income (Company's basis)	$ 1,088	$ 1,025	$ 2,321	$ 2,321

Investment in Unconsolidated Ventures (Details Textuals)	6 Months Ended
	Jun. 30, 2011 USD ($) sqft	Dec. 31, 2010 USD ($)
Additional Investment In Unconsolidated Ventures (Textuals) [Abstract]
Investment in real estate ventures, at equity	$ 82,927,000	$ 84,372,000
Area of undeveloped parcel of land (in acres) owned by a Real Estate Venture \| sqft	3
Unconsolidated real estate ventures [Member]
Additional Investment In Unconsolidated Ventures (Textuals) [Abstract]
Investment in real estate ventures, at equity	$ 82,927,000	$ 84,372,000
Guaranteed repayment of loans on behalf of a certain Real Estate Venture	700,000
Income from Real estate venture	$ 600

Investment in Unconsolidated Ventures (Details Textuals 1) $ in Millions	6 Months Ended
	Jun. 30, 2011 USD ($) sqft	Dec. 31, 2012 USD ($)	Jul. 29, 2011 USD ($) sqft	Nov. 30, 2010 USD ($)
Investment in Unconsolidated Ventures (Textuals) [Abstract]
Number of unconsolidated Real Estate Ventures	16
Number of office buildings owned by 14 Real Estate Ventures	49
Number of real estate ventures that owns 49 office buildings	14
Net rentable square feet of 49 office buildings owned the 14 Real Estate Ventures \| sqft	6,100,000
Number of rooms in a hotel property developed by one Real Estate Venture	137
Minimum ownership interest in unconsolidated Real Estate Ventures	10.00%
Maximum ownership interest in unconsolidated Real Estate Ventures	65.00%
Percentage of interest acquired in partnerships				25.00%
Interest acquired in partnerships, Number				2
Number of office buildings owned				2
Percentage of interest acquired in partnerships by other partner				75.00%
Initial contribution for acquisition of partnerships				$ 5.0
Contribution for acquisition of partnerships				$ 25.0
Remaining portion of contribution		$ 20.0
Company's ownership percentage in the Real Estate Venture			3.00%
Net rentable square feet of properties sold \| sqft			347,620
Sales price of properties sold			$ 86.7
Gain on sale of ownership interest	$ 2.8
Property occupied as of date of sale	87.00%

Deferred Costs (Details) - USD ($) $ in Thousands	Jun. 30, 2011	Dec. 31, 2010
Deferred Costs
Leasing Costs, Total Cost	$ 133,734	$ 123,724
Financing Costs, Total Cost	39,605	37,257
Total Cost	173,339	160,981
Leasing Costs, Accumulated Amortization	(48,223)	(43,930)
Financing Costs, Accumulated Amortization	(11,618)	(10,934)
Total, Accumulated Amortization	(59,841)	(54,864)
Leasing Costs, Deferred Costs, net	85,511	79,794
Financing Costs, Deferred Costs, net	27,987	26,323
Deferred Costs	$ 113,498	$ 106,117

Deferred Costs (Details Textuals) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
Deferred Costs (Details Textuals) - USD ($) $ in Millions	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Deferred Costs (Textuals) [Abstract]
Capitalized internal direct leasing costs	$ 1.7	$ 1.3	$ 3.2	$ 3.1

Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2011	Dec. 31, 2010
Intangible assets
Total Cost	$ 194,483	$ 222,160
Accumulated Amortization	(116,082)	(124,698)
Intangible assets, net	78,401	97,462
Below market leases acquired	25,556	29,233
Customer Relationships [Member]
Intangible assets
Total Cost	80,242	95,385
Accumulated Amortization	(46,041)	(52,113)
Intangible assets, net	34,201	43,272
Leases, Acquired-in-Place [Member]
Intangible assets
Total Cost	97,523	108,456
Accumulated Amortization	(61,390)	(63,010)
Intangible assets, net	36,133	45,446
Above market tenant leases acquired [Member]
Intangible assets
Total Cost	16,718	18,319
Accumulated Amortization	(8,651)	(9,575)
Intangible assets, net	8,067	8,744
Below market ground lease acquired [Member]
Intangible assets
Total Cost	66,402	67,198
Accumulated Amortization	$ (40,846)	$ (37,965)

Intangible Assets (Details 1) $ in Thousands	6 Months Ended
Intangible Assets (Details 1) $ in Thousands	Jun. 30, 2011 USD ($)
Assets, Total [Member]
Annual amortization of intangible assets and liabilities
2011 (six months remaining)	$ 14,510
2012	20,705
2013	12,452
2014	9,481
2015	6,717
Thereafter	14,536
Total	78,401
Liabilities, Total [Member]
Annual amortization of intangible assets and liabilities
2011 (six months remaining)	3,581
2012	6,447
2013	5,902
2014	4,334
2015	2,158
Thereafter	3,134
Total	$ 25,556

Debt Obligations (Details) - USD ($) $ in Thousands	Jun. 30, 2011	Dec. 31, 2010
Consolidated debt obligations
Long-term Debt, Gross		$ 59,800
Plus: unamortized fixed-rate debt premiums (discounts), net	$ 7,427
Less: unamortized exchangeable debt discount	400	900
Total mortgage indebtedness	588,823	711,789
Total unsecured indebtedness	2,466,021
Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	590,043	712,246
Plus: unamortized fixed-rate debt premiums (discounts), net	(1,220)	(457)
Total mortgage indebtedness	588,823	711,789
Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	1,883,405	1,722,326
Less: unamortized exchangeable debt discount	(362)	(906)
Less: unamortized fixed-rate debt discounts, net	(5,845)	(2,763)
Total unsecured indebtedness	1,877,198	1,718,657
Total unsecured indebtedness	2,466,021	2,430,446
$345.0M 3.875% Guaranteed Exchangeable Notes due 2026 [Member] \| Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 59,835	59,835
Effective interest rate	5.50%
Debt Instrument, Maturity Date	Oct-11
Bank Term Loan [Member] \| Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 183,000	183,000
Effective interest rate	LIBOR + 0.800%
Debt Instrument, Maturity Date	Jun-12
Credit Facility [Member] \| Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 42,000	183,000
Effective interest rate	LIBOR + 0.725%
Debt Instrument, Maturity Date	Jun-12
$300.0M 5.750% Guaranteed Notes due 2012 [Member] \| Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 153,694	175,200
Effective interest rate	5.73%
Debt Instrument, Maturity Date	Apr-12
$250.0M 5.400% Guaranteed Notes due 2014 [Member] \| Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 242,681	242,681
Effective interest rate	5.53%
Debt Instrument, Maturity Date	Nov-14
$250.0M 7.500% Guaranteed Notes due 2015 [Member] \| Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 248,585	250,000
Effective interest rate	7.77%
Debt Instrument, Maturity Date	May-15
$250.0M 6.000% Guaranteed Notes due 2016 [Member] \| Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 250,000	250,000
Effective interest rate	5.95%
Debt Instrument, Maturity Date	Apr-16
$300.0M 5.700% Guaranteed Notes due 2017 [Member] \| Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 300,000	300,000
Effective interest rate	5.68%
Debt Instrument, Maturity Date	May-17
$325.0M 4.950% Guaranteed Notes due 2018 [Member] \| Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 325,000	0
Effective interest rate	5.14%
Debt Instrument, Maturity Date	Apr-18
Indenture IA (Preferred Trust I) [Member] \| Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 27,062	27,062
Effective interest rate	LIBOR + 1.25%
Debt Instrument, Maturity Date	Mar-35
Indenture IB (Preferred Trust I) [Member] \| Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 25,774	25,774
Effective interest rate	LIBOR + 1.25%
Debt Instrument, Maturity Date	Apr-35
Indenture II (Preferred Trust II) [Member] \| Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 25,774	25,774
Effective interest rate	LIBOR + 1.25%
Debt Instrument, Maturity Date	Jul-35
Arboretum I, II, III & V [Member] \| Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 0	20,386
Effective interest rate	7.59%
Debt Instrument, Maturity Date	Jul-11
Midlantic Drive/Lenox Drive/DCC I [Member] \| Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 0	56,514
Effective interest rate	8.05%
Debt Instrument, Maturity Date	Oct-11
Research Office Center [Member] \| Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 0	39,145
Effective interest rate	5.30%
Debt Instrument, Maturity Date	Oct-11
Concord Airport Plaza [Member] \| Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 33,914	34,494
Effective interest rate	5.55%
Debt Instrument, Maturity Date	Jan-12
Newtown Square/Berwyn Park/Libertyview [Member] \| Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 57,334	58,102
Effective interest rate	7.25%
Debt Instrument, Maturity Date	May-13
Southpoint III [Member] \| Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 2,249	2,597
Effective interest rate	7.75%
Debt Instrument, Maturity Date	Apr-14
Tysons Corner [Member] \| Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 95,698	96,507
Effective interest rate	5.36%
Debt Instrument, Maturity Date	Aug-15
Two Logan Square [Member] \| Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 89,800	89,800
Effective interest rate	7.57%
Debt Instrument, Maturity Date	Apr-16
One Logan Square [Member] \| Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 60,000	60,000
Effective interest rate	4.50%
Debt Instrument, Maturity Date	Jul-16
IRS Philadelphia Campus [Member] \| Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 205,676	208,366
Effective interest rate	6.95%
Debt Instrument, Maturity Date	Sep-30
Cira South Garage [Member] \| Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 45,372	$ 46,335
Effective interest rate	7.11%
Debt Instrument, Maturity Date	Sep-30

Debt Obligations (Details 1) $ in Thousands	Jun. 30, 2011 USD ($)
Summary of debt repurchases
2011	$ 6,339
2012	424,630
2013	67,037
2014	255,016
2015	348,742
Thereafter	1,371,684
Total principal payments	2,473,448
Net unamortized premiums/(discounts)	(7,427)
Total Debt Obligations	$ 2,466,021

Debt Obligations (Details 2) $ in Thousands	6 Months Ended
Debt Obligations (Details 2) $ in Thousands	Jun. 30, 2011 USD ($)
Schedule of principal payments of debt obligations
Repurchase Amount	$ 23,931
Principal	22,921
Loss	(1,032)
Deferred Financing Amortization	90
2012 5.750% Notes [Member]
Schedule of principal payments of debt obligations
Repurchase Amount	22,331
Principal	21,506
Loss	(821)
Deferred Financing Amortization	82
2015 7.500% Notes [Member]
Schedule of principal payments of debt obligations
Repurchase Amount	1,600
Principal	1,415
Loss	(211)
Deferred Financing Amortization	$ 8

Debt Obligations (Details Textuals)	6 Months Ended		12 Months Ended
Debt Obligations (Details Textuals)	Jun. 30, 2011 USD ($)	Jun. 30, 2010	Dec. 31, 2010	Jul. 29, 2011 USD ($)	Mar. 31, 2011
Debt obligations (Textuals)
Interest rate floor on a monthly basis	0.055		0.055
Interest rate on Loans					4.95%
Secured Debt [Member]
Debt obligations (Textuals)
Weighted average effective interest rate on mortgage notes payable	6.50%	6.43%
Unsecured Debt [Member]
Debt obligations (Textuals)
Maximum amount by which the Company may increase its credit facility	$ 800,000,000
Borrowings under the credit facility	42,000,000
Unused availability under the Credit Facility	$ 547,700,000
Weighted-average interest rate on Credit Facility borrowings	1.01%	1.01%
Weighted average interest rate on the Credit Facility	0.99%	1.07%
Letter of Credit [Member] \| Unsecured Debt [Member]
Debt obligations (Textuals)
Borrowings under the credit facility	$ 10,300,000
Bank Term Loan [Member] \| Credit Facility [Member]
Debt obligations (Textuals)
Maturity Date	Jun. 29, 2011
Extended Maturity date	Jun. 29, 2012
Extension fee				$ 1,200,000
Payment of extension fee under the Credit Facility	15 basis points of the committed amount under the Credit Facility
$345.0M 3.875% Guaranteed Exchangeable Notes due 2026 [Member]
Debt obligations (Textuals)
Debt instrument, face amount	$ 345,000,000
Interest rate on Loans	3.875%
Carrying amount of the equity component	$ 24,400,000
$345.0M 3.875% Guaranteed Exchangeable Notes due 2026 [Member] \| Unsecured Debt [Member]
Debt obligations (Textuals)
Maturity Date	Oct. 20, 2011
Redemption price under right to redeem guaranteed exchangeable notes	100% of the principal amount plus accrued and unpaid interest
Initial exchange rate for Guaranteed Exchangeable Notes	25.4065 shares per $1,000 principal amount of notes
Initial exchange price per share	$ 39.36
$300.0M 5.750% Guaranteed Notes due 2012 [Member]
Debt obligations (Textuals)
Debt instrument, face amount	$ 300,000,000
Interest rate on Loans	5.75%
$250.0M 5.400% Guaranteed Notes due 2014 [Member]
Debt obligations (Textuals)
Debt instrument, face amount	$ 250,000,000
Interest rate on Loans	5.40%
$250.0M 7.500% Guaranteed Notes due 2015 [Member]
Debt obligations (Textuals)
Debt instrument, face amount	$ 250,000,000
Interest rate on Loans	7.50%
$250.0M 6.000% Guaranteed Notes due 2016 [Member]
Debt obligations (Textuals)
Debt instrument, face amount	$ 250,000,000
Interest rate on Loans	6.00%
$300.0M 5.700% Guaranteed Notes due 2017 [Member]
Debt obligations (Textuals)
Debt instrument, face amount	$ 300,000,000
Interest rate on Loans	5.70%
$325.0M 4.950% Guaranteed Notes due 2018 [Member]
Debt obligations (Textuals)
Debt instrument, face amount	$ 325,000,000
Interest rate on Loans	4.95%
One Logan Square [Member] \| Secured Debt [Member]
Debt obligations (Textuals)
Interest rate floor on a monthly basis	0.0450

Debt Obligations (Details Textuals 1) - USD ($)	3 Months Ended		6 Months Ended
Debt Obligations (Details Textuals 1) - USD ($)	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Debt obligations (Additional) (Textuals)
Unamortized fixed-rate debt premium	$ 300,000		$ 300,000
Repurchased outstanding unsecured notes			22,921,000
Principal amount outstanding on Guaranteed Exchangeable Notes	59,800,000		59,800,000
Long-term Debt, Gross					$ 59,800,000
Less: unamortized exchangeable debt discount	400,000		400,000		$ 900,000
Contractual coupon interest recognized on exchangeable debt	600,000	$ 800,000	1,200,000	$ 1,900,000
Interest on amortization of debt discount	300,000	400,000	600,000	900,000
Debt discount write-offs resulting from debt repurchases	$ 0	$ 500,000	$ 0	$ 1,600,000

Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2011	Dec. 31, 2010
Company's estimates of fair value differ from the carrying amounts
Mortgage payable, net of discounts, Carrying Amount	$ 588,823	$ 711,789
Mortgage payable, net of discounts, Fair Value	602,815	726,348
Unsecured notes payable, net of discounts, Carrying Amount	1,573,588	1,274,047
Unsecured notes payable, net of discounts, Fair Value	1,726,338	1,338,743
Variable Rate Debt Instruments, Carrying Amount	303,610	444,610
Variable Rate Debt Instruments, Fair Value	295,131	432,556
Notes Receivable, Carrying Amount	32,255	31,216
Notes Receivable, Fair Value	$ 29,995	$ 28,921

Fair Value of Financial Instruments (Details Textuals) $ in Millions	Jun. 30, 2011 USD ($)
Fair Value of Financial Instruments (Textuals) [Abstract]
Gross deferred gain on sale of properties	$ 12.9

Risk Management and Use of Financial Instruments (Details) $ in Millions	1 Months Ended	3 Months Ended			6 Months Ended
	Mar. 31, 2011 USD ($)	Jun. 30, 2011 USD ($)	Mar. 31, 2011 USD ($)	Jun. 30, 2010	Jun. 30, 2011 USD ($)	Jun. 30, 2010
Risk Management and use of Financial Instruments (Textuals) [Abstract]
Anticipation of the offering of unsecured guaranteed notes due	$ 325.0		$ 325.0
Interest rates of unsecured guaranteed notes due	4.95%		4.95%
Treasury lock agreements					seven intra-day treasury lock agreements
Total notional amount of the treasury lock agreements		$ 230.0			$ 230.0
Expiration period of treasury lock agreements					7 years
Treasury rates, Minimum			2.858%
Treasury rates, Average			2.873%
Treasury rates, Maximum			2.891%
Fair Value Treasury Lock Agreements	$ 0.6
Total expense of debt offering		$ 0.6			$ 0.6
No. of tenants accounted for 10% or more of the Company's rents		0		0	0	0

Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Discontinued Operations (Details) - USD ($) $ in Thousands	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Revenue:
Rents	$ 120,416	$ 113,006	$ 241,145	$ 227,048
Tenant reimbursements	18,969	17,234	42,025	38,050
Other	1,341	1,022	2,439	1,943
Total revenue	145,407	135,497	293,611	276,497
Expenses:
Property operating expenses	40,595	38,018	86,614	82,336
Real estate taxes	14,474	13,383	28,871	26,121
Depreciation and amortization	58,014	51,289	109,688	103,318
Total operating expenses	120,479	110,836	240,323	227,425
Income from discontinued operations before gain on sale of interests in real estate	57	268	63	675
Net gain on disposition of discontinued operations	3,836		3,836	6,349
Income from discontinued operations	3,893	268	3,899	7,024
Discontinued Operations [Member]
Revenue:
Rents	199	1,526	475	2,993
Tenant reimbursements	18	642	83	1,357
Other		2	(78)	2
Total revenue	217	2,170	480	4,352
Expenses:
Property operating expenses	101	751	260	1,606
Real estate taxes	19	315	70	631
Depreciation and amortization	40	836	87	1,440
Total operating expenses	$ 160	$ 1,902	$ 417	$ 3,677

Discontinued Operations (Details Textuals)	3 Months Ended	6 Months Ended
Discontinued Operations (Details Textuals)	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Discontinued Operations (Textuals) [Abstract]
Number of properties sold	9	1	9

Non-Controlling Interests in The Parent Company (Details) - USD ($) $ in Millions	Jun. 30, 2011	Dec. 31, 2010
Non-Controlling Interests in the Parent Company (Textuals) [Abstract]
Aggregate amount related to non-controlling interests classified within equity	$ 123.4	$ 128.3
Settlement value of non controlling interest in operating partnership	$ 113.7	$ 115.4

Beneficiaries Equity of The Parent Company (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Numerator
Loss from continuing operations, Basic	$ (10,127)	$ (5,868)	$ (10,623)	$ (13,023)
Loss from continuing operations, Diluted	(10,127)	(5,868)	(10,623)	(13,023)
Net loss from continuing operations attributable to non-controlling interests, Basic	243	165	294	360
Net loss from continuing operations attributable to non-controlling interests, Diluted	243	165	294	360
Amount allocable to unvested restricted shareholders, Basic	(121)	(128)	(263)	(256)
Amount allocable to unvested restricted shareholders, Diluted	(121)	(128)	(263)	(256)
Distribution to Preferred Shares	(1,998)	(1,998)	(3,996)	(3,996)
Preferred share dividends, Diluted	(1,998)	(1,998)	(3,996)	(3,996)
Loss from continuing operations available to common shareholders, Basic	(12,003)	(7,829)	(14,588)	(16,915)
Loss from continuing operations available to common shareholders, Diluted	(12,003)	(7,829)	(14,588)	(16,915)
Income from discontinued operations	3,893	268	3,899	7,024
Income (loss) from discontinued operations, Diluted	3,893	268	3,899	7,024
Net income from discontinued operations attributable to non-controlling interests - LP units	(78)	(6)	(78)	(150)
Discontinued operations attributable to non-controlling interests, diluted	(78)	(6)	(78)	(150)
Discontinued operations attributable to common shareholders, Basic	3,815	262	3,821	6,874
Discontinued operations attributable to common shareholders, Diluted	3,815	262	3,821	6,874
Net loss attributable to common shareholders, Basic	(8,188)	(7,567)	(10,767)	(10,041)
Net loss attributable to common shareholders, Diluted	$ (8,188)	$ (7,567)	$ (10,767)	$ (10,041)
Denominator
Weighted-average shares outstanding, Basic	135,342,538	131,510,924	134,962,093	130,146,853
Weighted-average shares outstanding, Diluted	135,342,538	131,510,924	134,962,093	130,146,853
Earnings per Common Share:
Loss from continuing operations attributable to common shareholders, Basic	$ (0.09)	$ (0.06)	$ (0.11)	$ (0.13)
Loss from continuing operations attributable to common shareholders, Diluted	(0.09)	(0.06)	(0.11)	(0.13)
Discontinued operations attributable to common shareholders, Basic	0.03	0.00	0.03	0.05
Discontinued operations attributable to common shareholders, Diluted	0.03	0.00	0.03	0.05
Net loss attributable to common shareholders, Basic	(0.06)	(0.06)	(0.08)	(0.08)
Net loss attributable to common shareholders, Diluted	$ (0.06)	$ (0.06)	$ (0.08)	$ (0.08)

Beneficiaries Equity of The Parent Company (DetailsTextuals) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	Jun. 30, 2010	Jul. 06, 2011	May 31, 2011	May 02, 2006
Beneficiaries Equity of The Parent Company (Textuals) [Abstract]
Redeemable limited partnership units excluded from the diluted earnings per share computations		9,809,759	2,809,108
Dividend declared per common share					$ 0.15
Amount of dividend declared				$ 20,500
Preferential return for series C		7.50%
Preferential return for series D		7.375%
Dividend paid for series C preferred shares	$ 900	$ 900
Dividend paid for series D preferred shares	$ 1,100	$ 1,100
Shares authorized for Equity Offering Program		15,000,000
Maximum percentage of Gross sale price per share, compensation to sales agents		2.00%
Issuance of Common Shares of Beneficial Interest, shares		679,285
Average sales price per share		$ 12.18
Issuance of Common Shares of Beneficial Interest		$ 8,272	$ 41,692
No of shares sold by the company	6,421,553
Remaining shares available for sales	8,578,447
Common partnership units issued to the parent company		679,285
Common shares capacity restored						3,500,000
Additional shares Expected to be purchased under program	500,000	500,000

Partners Equity of The Operating Partnership (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Numerator
Loss from continuing operations, Basic	$ (10,127)	$ (5,868)	$ (10,623)	$ (13,023)
Loss from continuing operations, Diluted	(10,127)	(5,868)	(10,623)	(13,023)
Amount allocable to unvested restricted shareholders, Basic	(121)	(128)	(263)	(256)
Amount allocable to unvested restricted unitholders, Diluted	(121)	(128)	(263)	(256)
Distribution to Preferred Shares	(1,998)	(1,998)	(3,996)	(3,996)
Preferred share dividends, Diluted	(1,998)	(1,998)	(3,996)	(3,996)
Discontinued operations attributable to common unitholders	3,893	268	3,899	7,024
Net loss attributable to common unitholders, Basic	(8,188)	(7,567)	(10,767)	(10,041)
Net income available to common unitholders, Diluted	$ (8,188)	$ (7,567)	$ (10,767)	$ (10,041)
Denominator
Weighted-average units outstanding, Basic	135,342,538	131,510,924	134,962,093	130,146,853
Weighted-average units outstanding, Diluted	135,342,538	131,510,924	134,962,093	130,146,853
Loss per common share:
Loss from continuing operations attributable to common shareholders, Basic	$ (0.09)	$ (0.06)	$ (0.11)	$ (0.13)
Loss from continuing operations attributable to common shareholders, Diluted	(0.09)	(0.06)	(0.11)	(0.13)
Discontinued operations attributable to common shareholders, Basic	0.03	0.00	0.03	0.05
Discontinued operations attributable to common shareholders, Diluted	0.03	0.00	0.03	0.05
Net loss attributable to common shareholders, Basic	(0.06)	(0.06)	(0.08)	(0.08)
Net loss attributable to common shareholders, Diluted	$ (0.06)	$ (0.06)	$ (0.08)	$ (0.08)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Loss from continuing operations, Basic	$ (10,127)	$ (5,868)	$ (10,623)	$ (13,023)
Loss from continuing operations, Diluted	(10,127)	(5,868)	(10,623)	(13,023)
Amount allocable to unvested restricted shareholders, Basic	(121)	(128)	(263)	(256)
Amount allocable to unvested restricted unitholders, Diluted	(121)	(128)	(263)	(256)
Distribution to Preferred Shares	(1,998)	(1,998)	(3,996)	(3,996)
Preferred share dividends, Diluted	(1,998)	(1,998)	(3,996)	(3,996)
Loss from continuing operations available to common unitholders	(12,246)	(7,994)	(14,882)	(17,275)
Loss from continuing operations available to common unitholders, Diluted	(12,246)	(7,994)	(14,882)	(17,275)
Discontinued operations attributable to common unitholders	3,893	268	3,899	7,024
Discontinued operations attributable to common unitholders, Diluted	3,893	268	3,899	7,024
Net loss attributable to common unitholders, Basic	(8,353)	(7,726)	(10,983)	(10,251)
Net income available to common unitholders, Diluted	$ (8,353)	$ (7,726)	$ (10,983)	$ (10,251)
Denominator
Weighted-average units outstanding, Basic	145,220,764	134,320,032	144,852,515	132,955,961
Weighted-average units outstanding, Diluted	145,220,764	134,320,032	144,852,515	132,955,961
Loss per common share:
Loss from continuing operations attributable to common shareholders, Basic	$ (0.09)	$ (0.06)	$ (0.11)	$ (0.13)
Loss from continuing operations attributable to common shareholders, Diluted	(0.09)	(0.06)	(0.11)	(0.13)
Discontinued operations attributable to common shareholders, Basic	0.03	0.00	0.03	0.05
Discontinued operations attributable to common shareholders, Diluted	0.03	0.00	0.03	0.05
Net loss attributable to common shareholders, Basic	(0.06)	(0.06)	(0.08)	(0.08)
Net loss attributable to common shareholders, Diluted	$ (0.06)	$ (0.06)	$ (0.08)	$ (0.08)

Partners Equity of The Operating Partnership (DetailsTextuals) - USD ($)	1 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	May 31, 2011	Aug. 05, 2010
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Preferential return for series C		7.50%
Preferential return for series D		7.375%
Net proceeds contributed by Parent Company		$ 8,000,000
Issue of shares under Offering Program		679,285
Market price of shares on acquisition date				$ 11.54
Dividend rate				$ 0.60
Redemption price of partnership unit				Either for an amount, per unit, of cash equal to the market price of one of the Parent Company’s common share (based on the five-day trading average ending on the date of the exchange) or for one of the Parent Company’s common share
7.50% Series D Preferred Shares
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Distributions paid Preferred unitholders	$ 900,000
7.375% Series E Preferred Shares
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Distributions paid Preferred unitholders	$ 1,100,000
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Distribution Declared per common partnership unit			$ 0.15
Distribution Declared for common partnership unitholders			$ 20,500,000
Common partnership units issued to the parent company		679,285
Class F (2010) Units [Member] \| BRANDYWINE OPERATING PARTNERSHIP, L.P.
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Partnership units issued for acquisition				7,111,112

Share Based and Deferred Compensation (Details)	6 Months Ended
Share Based and Deferred Compensation (Details)	Jun. 30, 2011 USD ($) $ / shares shares
Option activity
Outstanding at January 1, 2011, shares \| shares	3,116,611
Granted, shares \| shares	603,241
Exercised, shares \| shares	(76,887)
Outstanding at June 30, 2011, shares \| shares	3,642,965
Vested/Exercisable at June 30, 2011, shares \| shares	2,331,021
Outstanding at January 1, 2011, Weighted Average Exercise Price \| $ / shares	$ 14.56
Granted, Weighted Average Exercise Price \| $ / shares	11.89
Exercised, Weighted Average Exercise Price \| $ / shares	2.91
Outstanding at June30, 2011, Weighted Average Exercise Price \| $ / shares	14.37
Vested/Exercisable at June 30, 2011, Weighted Average Exercise Price \| $ / shares	$ 16.75
Outstanding at January 1, 2011, Weighted Average Remaining Contractual Term	7.81
Granted, Weighted Average Remaining Contractual Term (in years)	9.68
Outstanding at June 30, 2011, Weighted Average Remaining Contractual Term	7.70
Vested/Exercisable at June 30, 2011, Weighted Average Remaining Contractual Term	7.05
Outstanding at January 1, 2011, Aggregate Intrinsic Value \| $	$ (9,080,625)
Granted, Aggregate Intrinsic Value \| $	(180,972)
Outstanding at June 30, 2011, Aggregate Intrinsic Value \| $	(10,115,971)
Vested/Exercisable at June 30, 2011, Aggregate Intrinsic Value \| $	$ (11,802,863)

Share Based and Deferred Compensation (Details 1) - Restricted Share Awards [Member]	6 Months Ended
	Jun. 30, 2011 $ / shares shares
Company's restricted share activity
Non-vested at January 1, 2011, shares \| shares	851,278
Non-vested at January 1, 2011, Weighted Average Grant Date Fair value \| $ / shares	$ 10.75
Granted, shares \| shares	197,035
Granted, Weighted Average Grant Date Fair value \| $ / shares	$ 11.92
Vested, shares \| shares	(237,541)
Vested, Weighted Average Grant Date Fair value \| $ / shares	$ 19.76
Forfeited, shares \| shares	(2,009)
Forfeited, Weighted Average Grant Date Fair Value \| $ / shares	$ 15.04
Non-vested at June 30, 2011, shares \| shares	808,763
Non-vested at June 30, 2011, Weighted Average Grant Date Fair value \| $ / shares	$ 9.47

Share Based and Deferred Compensation (Details Textuals) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Mar. 31, 2011	Jun. 30, 2011 USD ($) shares	Jun. 30, 2010 USD ($) shares	Jun. 30, 2011 USD ($) shares	Jun. 30, 2010 USD ($) shares	Jun. 30, 2009 USD ($)	May 24, 2011 shares	Mar. 02, 2011 shares	Dec. 31, 2010 shares	Mar. 04, 2010 shares	Apr. 01, 2009 shares
Share Based and Deferred Compensation (Textuals) [Abstract]
Options outstanding under equity incentive plan \| shares		3,642,965		3,642,965					3,116,611
Compensation expense recognized		$ 1.6	$ 1.8	$ 3.3	$ 3.1
Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Dating				10 Years
Employee Service Share-based Compensation, Capitalized Amount		$ 0.4	0.4	$ 0.7	0.6
Stock Option [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Options outstanding under equity incentive plan \| shares		3,642,965		3,642,965
Unvested options \| shares		1,311,943		1,311,943
Unrecognized compensation expenses		$ 3.1		$ 3.1
Weighted average period over which options will be recognized				2.0
Compensation expense recognized		0.4	0.3	$ 0.7	0.5
Vesting Period				over three years
Employee Service Share-based Compensation, Capitalized Amount		0.1		$ 0.2
Voluntary termination of employment Terms	after reaching age 57 and accumulating at least 15 years of service with the Company
Restricted Share Awards [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Unrecognized compensation expenses		5.1		$ 5.1
Weighted average period over which options will be recognized				1.6
Compensation expense recognized		$ 0.8	1.0	$ 1.6	1.8
Restricted shares outstanding \| shares		808,763		808,763					851,278
Vesting Period	after three years from the grant date			three to seven years from initial grant date
Employee Service Share-based Compensation, Capitalized Amount		$ 0.1	0.2	$ 0.3	0.4
Voluntary termination of employment Terms	after reaching age 57 and accumulating at least 15 years of service with the Company
Restricted Performance Share Units Plan [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Compensation expense recognized		0.5	0.3	$ 0.8	0.5
Vesting Period				3
Employee Service Share-based Compensation, Capitalized Amount		0.1		$ 0.2
Voluntary termination of employment Terms	after reaching age 57 and accumulating at least 15 years of service with the Company
Maximum number of shares to be delivered at the end of the measurement period relative to the total shareholder return				equal a certain percentage (not to exceed 200%) of the participant’s base units
Fair value of awards on the grant date				$ 2.0	2.0	$ 1.1
Outperformance Program [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Compensation expense recognized		0.1	0.1	0.1	0.2
Fair value of awards on the grant date				5.9
Employee Share Purchase Plan [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Compensation expense recognized		$ 0.1	0.2	$ 0.1	0.2
Aggregate share-based awards awarded to executives \| shares		1,250,000		1,250,000
Share purchases made by employees under ESPP				85% of the average closing price per share for a specified period
Maximum participant contribution under 2011 plan				limited to the lesser of 20% of compensation or $50,000
Purchase price of shares purchased under ESPP		$ 0.1	$ 0.2	$ 0.2	0.3
Deferred Compensation Plan [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Net increase in compensation costs due to change in market value of participant investment in plan				0.4	0.2
Net decrease in compensation costs due to change in market value of participant investment in plan				$ 0.4	$ 0.2
Number of shares to be issued under deferred compensation plan included in total shares outstanding \| shares		300,000	300,000	300,000	300,000
Executive Officer [Member] \| Stock Option [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Aggregate share-based awards awarded to executives \| shares							101,437	603,241
Executive Officer [Member] \| Restricted Share Awards [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Aggregate share-based awards awarded to executives \| shares								174,012
Executive Officer [Member] \| Restricted Performance Share Units Plan [Member]
Share Based and Deferred Compensation (Textuals) [Abstract]
Aggregate share-based awards awarded to executives \| shares								124,293		120,955	488,292

Tax Credit Transactions (DetailsTextuals) $ in Thousands	1 Months Ended			3 Months Ended		6 Months Ended
Tax Credit Transactions (DetailsTextuals) $ in Thousands	Jun. 30, 2010 USD ($)	Dec. 31, 2009 USD ($)	Nov. 30, 2008 USD ($)	Jun. 30, 2011 USD ($)	Jun. 30, 2010 USD ($)	Jun. 30, 2011 USD ($)	Jun. 30, 2010 USD ($)	Dec. 31, 2010 USD ($)	Nov. 17, 2008 sqft
Tax Credit Transactions (Textuals) [Abstract]
Amount received in advance for project cost							$ 27,396
Limit on tax credit claims under the Community Renewal Tax Relief						up to 39% of qualified investments in qualified, active low-income businesses or ventures
Deferred transaction costs				$ 113,498		$ 113,498		$ 106,117
Historic Tax Credit Transaction [Member]
Tax Credit Transactions (Textuals) [Abstract]
Area of IRS Philadelphia Campus building (in square foot) \| sqft									862,692
Percentage of building leased to IRS									100.00%
Tax credit conditions						20% recapture per year beginning one year after the completion of the IRS Philadelphia Campus
Contribution allocated in non controlling interest				2,200		$ 2,200		2,100
Recognition of cash received as revenue net of allocated expenses on or after September 2011, period						Over the five year tax credit recapture period as defined in the Internal Revenue Code
Deferred transaction costs				4,300		$ 4,300		4,300
Rate of return on noncontrolling interest expected						0.02
Accretion of non controlling interest liability				300	$ 300	$ 700	$ 400
New Markets Tax Credit Transaction [Member]
Tax Credit Transactions (Textuals) [Abstract]
Tax credit conditions						100% recapture for a period of seven years as provided in the Internal Revenue Code
Deferred transaction costs				5,300		$ 5,300		5,300
Expected benefit from qualified program						7,800
USB [Member] \| Historic Tax Credit Transaction [Member]
Tax Credit Transactions (Textuals) [Abstract]
Agreed contribution in project cost by USB			$ 64,800
Amount received in advance for project cost	$ 27,400	$ 23,800	$ 10,200
Amount to be received for project cost						3,000
USB contributions presented within deferred income				61,400		61,400		61,400
USB [Member] \| New Markets Tax Credit Transaction [Member]
Tax Credit Transactions (Textuals) [Abstract]
USB contributions presented within deferred income				$ 13,300		$ 13,300		$ 13,300

Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Segment Information (Details) - USD ($) $ in Thousands	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Real estate investments, at cost:
Operating properties	$ 4,885,041		$ 4,885,041		$ 4,834,111
Construction-in-progress	33,314		33,314		33,322
Land inventory	120,245		120,245		110,055
Total revenue	145,407	$ 135,497	293,611	$ 276,497
Property operating expenses, real estate taxes and third party management expenses	56,575	52,894	118,501	111,362
Net operating income	88,832	82,603	175,110	165,135
Pennsylvania Suburbs [Member]
Real estate investments, at cost:
Operating properties	1,210,274		1,210,274		1,199,957
Construction-in-progress	0		0		0
Land inventory	0		0		0
Total revenue	39,137	37,332	79,431	76,814
Property operating expenses, real estate taxes and third party management expenses	13,572	12,866	30,366	29,622
Net operating income	25,565	24,466	49,065	47,192
Philadelphia CBD [Member]
Real estate investments, at cost:
Operating properties	928,880		928,880		911,354
Construction-in-progress	0		0		0
Land inventory	0		0		0
Total revenue	30,573	18,412	62,423	36,962
Property operating expenses, real estate taxes and third party management expenses	11,220	7,956	23,439	15,793
Net operating income	19,353	10,456	38,984	21,169
Metropolitan, D.C. [Member]
Real estate investments, at cost:
Operating properties	1,366,282		1,366,282		1,359,776
Construction-in-progress	0		0		0
Land inventory	0		0		0
Total revenue	32,616	34,661	65,258	69,403
Property operating expenses, real estate taxes and third party management expenses	12,190	11,996	24,514	24,370
Net operating income	20,426	22,665	40,744	45,033
New Jersey/ Delaware [Member]
Real estate investments, at cost:
Operating properties	568,992		568,992		568,413
Construction-in-progress	0		0		0
Land inventory	0		0		0
Total revenue	21,098	22,647	42,429	47,940
Property operating expenses, real estate taxes and third party management expenses	10,004	10,543	21,751	22,787
Net operating income	11,094	12,104	20,678	25,153
Richmond, Virginia [Member]
Real estate investments, at cost:
Operating properties	306,243		306,243		294,406
Construction-in-progress	0		0		0
Land inventory	0		0		0
Total revenue	9,277	8,769	18,076	18,168
Property operating expenses, real estate taxes and third party management expenses	3,623	3,165	7,011	6,824
Net operating income	5,654	5,604	11,065	11,344
Austin, Texas [Member]
Real estate investments, at cost:
Operating properties	254,920		254,920		254,019
Construction-in-progress	0		0		0
Land inventory	0		0		0
Total revenue	7,637	7,966	15,750	15,965
Property operating expenses, real estate taxes and third party management expenses	3,420	3,441	6,514	6,762
Net operating income	4,217	4,525	9,236	9,203
California [Member]
Real estate investments, at cost:
Operating properties	249,450		249,450		246,186
Construction-in-progress	0		0		0
Land inventory	0		0		0
Total revenue	5,382	5,967	10,791	11,871
Property operating expenses, real estate taxes and third party management expenses	2,821	2,956	5,515	5,684
Net operating income	2,561	3,011	5,276	6,187
Corporate [Member]
Real estate investments, at cost:
Operating properties	0		0		0
Construction-in-progress	33,314		33,314		33,322
Land inventory	120,245		120,245		$ 110,055
Total revenue	(313)	(257)	(547)	(626)
Property operating expenses, real estate taxes and third party management expenses	(275)	(29)	(609)	(480)
Net operating income	$ (38)	$ (228)	$ 62	$ (146)

Segment Information (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Segment Information (Details 1) - USD ($) $ in Thousands	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Reconciliation of consolidated net operating income
Consolidated net operating income	$ 88,832	$ 82,603	$ 175,110	$ 165,135
Less:
Interest expense	(34,738)	(31,210)	(67,131)	(62,734)
Interest expense - amortization of deferred financing costs	(1,070)	(862)	(1,998)	(1,873)
Depreciation and amortization	(58,014)	(51,289)	(109,688)	(103,318)
Administrative expenses	(5,890)	(6,653)	(12,134)	(12,745)
Plus:
Interest income	421	963	862	1,828
Equity in income of real estate ventures	1,088	1,025	2,321	2,321
Net gain on sale of interests in real estate			2,791
Loss on early extinguishment of debt	(756)	(445)	(756)	(1,637)
Loss from continuing operations, Basic	(10,127)	(5,868)	(10,623)	(13,023)
Income from discontinued operations	3,893	268	3,899	7,024
Net loss	$ (6,234)	$ (5,600)	$ (6,724)	$ (5,999)

Commitments and Contingencies (Details) $ in Thousands	Jun. 30, 2011 USD ($)
Minimum future rental payments on non-cancelable leases
2011 (six months remaining)	$ 909
2012	1,818
2013	1,818
2014	1,909
2015	1,909
Thereafter	$ 289,897

Commitments and Contingencies (Details Textuals)	6 Months Ended
Commitments and Contingencies (Details Textuals)	Jun. 30, 2011 USD ($) sqft	Aug. 05, 2010 USD ($)
Commitments and Contingencies (Textuals) [Abstract]
Minimum remaining lease period	18
Maximum remaining lease period	92
Annual rental payment under ground lease	ten dollars through August 2022. 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.
Aggregate fair market rent future payment as of the date of acquisition		$ 27,400,000
Area of Two Logan Square in Philadelphia \| sqft	708,844
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	$ 2,900,000
Liability related to acquisition of TRC	700,000
Accretion Of Liability Related To Acquisition	2,900,000
Balance portion of acquisition related liability	$ 1,300,000
Company agreed not to sell acquired properties up to the period	15 years

Subsequent Events (Details) $ in Millions	Jun. 30, 2011 USD ($)
Subsequent Events (Textuals) [Abstract]
Company prepaid its Plymouth Meeting Executive Center mortgage debt without penalty	$ 60.0
Deferred financing costs	$ 0.8