Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Real estate investments:
Rental properties	$ 4,607,890	$ 4,726,169
Accumulated depreciation	(951,934)	(954,665)
Operating real estate investments, net	3,655,956	3,771,504
Construction-in-progress	53,468	48,950
Land inventory	92,776	102,439
Total real estate investments, net	3,802,200	3,922,893
Cash and cash equivalents	47,874	1,549
Accounts receivable, net	15,072	13,232
Accrued rent receivable, net	120,070	122,066
Investment in real estate ventures, at equity	184,802	193,555
Deferred costs, net	119,378	122,243
Intangible assets, net	66,104	70,620
Notes receivable	7,026	7,226
Other assets	62,778	53,325
Total assets	4,425,304	4,506,709
LIABILITIES AND BENEFICIARIES’ EQUITY
Mortgage notes payable	440,300	442,974
Unsecured credit facility	0	69,000
Unsecured term loans	450,000	450,000
Unsecured senior notes, net of discounts	1,503,632	1,503,356
Accounts payable and accrued expenses	81,626	71,579
Distributions payable	23,684	23,652
Deferred income, gains and rent	81,976	82,947
Acquired lease intangibles, net	31,902	33,859
Other liabilities	53,551	55,826
Total liabilities	2,666,671	2,733,193
Commitments and contingencies (Note 17)
Brandywine Realty Trust’s equity:
Preferred Shares	40	40
Common Shares of Brandywine Realty Trust’s beneficial interest, $0.01 par value; shares authorized 200,000,000; 143,712,578 and 143,538,733 issued and outstanding in 2013 and 2012, respectively	1,435	1,434
Additional paid-in capital	2,783,130	2,780,194
Deferred compensation payable in common shares	5,516	5,352
Common shares in grantor trust, 315,753 in 2013 and 290,745 in 2012	(5,516)	(5,352)
Cumulative earnings	483,635	479,734
Accumulated other comprehensive loss	(14,048)	(15,918)
Cumulative distributions	1,516,591	1,493,206
Total Brandywine Realty Trust’s equity	1,737,601	1,752,278
Non-controlling interests	21,032	21,238
Total equity	1,758,633	1,773,516
Total liabilities and equity	4,425,304	4,506,709
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Real estate investments:
Rental properties	4,607,890	4,726,169
Accumulated depreciation	(951,934)	(954,665)
Operating real estate investments, net	3,655,956	3,771,504
Construction-in-progress	53,468	48,950
Land inventory	92,776	102,439
Total real estate investments, net	3,802,200	3,922,893
Cash and cash equivalents	47,874	1,549
Accounts receivable, net	15,072	13,232
Accrued rent receivable, net	120,070	122,066
Investment in real estate ventures, at equity	184,802	193,555
Deferred costs, net	119,378	122,243
Intangible assets, net	66,104	70,620
Notes receivable	7,026	7,226
Other assets	62,778	53,325
Total assets	4,425,304	4,506,709
LIABILITIES AND BENEFICIARIES’ EQUITY
Mortgage notes payable	440,300	442,974
Unsecured credit facility	0	69,000
Unsecured term loans	450,000	450,000
Unsecured senior notes, net of discounts	1,503,632	1,503,356
Accounts payable and accrued expenses	81,626	71,579
Distributions payable	23,684	23,652
Deferred income, gains and rent	81,976	82,947
Acquired lease intangibles, net	31,902	33,859
Other liabilities	53,551	55,826
Total liabilities	2,666,671	2,733,193
Commitments and contingencies (Note 17)
Redeemable limited partnership units at redemption value;
Redeemable limited partnership units at redemption value; 1,845,737 issued and outstanding in 2013 and 2012	27,940	26,777
Brandywine Realty Trust’s equity:
Preferred Shares	96,850	96,850
General Partners' Capital Account	1,648,167	1,666,341
Accumulated other comprehensive loss	(14,324)	(16,452)
Total Brandywine Realty Trust’s equity	1,730,693	1,746,739
Total liabilities and equity	4,425,304	4,506,709
Series E Preferred Stock [Member]
Brandywine Realty Trust’s equity:
Total equity	$ 40	$ 40