Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Real estate investments:
Rental properties	$ 4,620,460	$ 4,726,169
Accumulated depreciation	(967,726)	(954,665)
Operating real estate investments, net	3,652,734	3,771,504
Construction-in-progress	51,260	48,950
Land inventory	94,444	102,439
Total real estate investments, net	3,798,438	3,922,893
Cash and cash equivalents	215,948	1,549
Accounts receivable, net	11,834	13,232
Accrued rent receivable, net	124,341	122,066
Investment in real estate ventures, at equity	176,875	193,555
Deferred costs, net	119,917	122,243
Intangible assets, net	59,919	70,620
Notes receivable	7,026	7,226
Other assets	52,091	53,325
Total assets	4,566,389	4,506,709
LIABILITIES AND BENEFICIARIES’ EQUITY
Mortgage notes payable	437,618	442,974
Unsecured credit facility	0	69,000
Unsecured term loans	450,000	450,000
Unsecured senior notes, net of discounts	1,492,127	1,503,356
Accounts payable and accrued expenses	70,434	71,579
Distributions payable	25,587	23,652
Deferred income, gains and rent	81,903	82,947
Acquired lease intangibles, net	30,455	33,859
Other liabilities	44,196	55,826
Total liabilities	2,632,320	2,733,193
Commitments and contingencies (Note 17)
Equity:
6.90% Preferred Shares/Units, issued and outstanding- 4,000,000 in 2013 and 2012	40	40
Common Shares of Brandywine Realty Trust’s beneficial interest, $0.01 par value; shares authorized 200,000,000; 156,662,644 and 143,538,733 issued and outstanding in 2013 and 2012, respectively	1,565	1,434
Additional paid-in capital	2,967,790	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	490,754	479,734
Accumulated other comprehensive loss	(4,601)	(15,918)
Cumulative distributions	1,541,896	1,493,206
Total Brandywine Realty Trust’s equity	1,913,652	1,752,278
Non-controlling interests	20,417	21,238
Total equity	1,934,069	1,773,516
Total liabilities and equity	4,566,389	4,506,709
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Real estate investments:
Rental properties	4,620,460	4,726,169
Accumulated depreciation	(967,726)	(954,665)
Operating real estate investments, net	3,652,734	3,771,504
Construction-in-progress	51,260	48,950
Land inventory	94,444	102,439
Total real estate investments, net	3,798,438	3,922,893
Cash and cash equivalents	215,948	1,549
Accounts receivable, net	11,834	13,232
Accrued rent receivable, net	124,341	122,066
Investment in real estate ventures, at equity	176,875	193,555
Deferred costs, net	119,917	122,243
Intangible assets, net	59,919	70,620
Notes receivable	7,026	7,226
Other assets	52,091	53,325
Total assets	4,566,389	4,506,709
LIABILITIES AND BENEFICIARIES’ EQUITY
Mortgage notes payable	437,618	442,974
Unsecured credit facility	0	69,000
Unsecured term loans	450,000	450,000
Unsecured senior notes, net of discounts	1,492,127	1,503,356
Accounts payable and accrued expenses	70,434	71,579
Distributions payable	25,587	23,652
Deferred income, gains and rent	81,903	82,947
Acquired lease intangibles, net	30,455	33,859
Other liabilities	44,196	55,826
Total liabilities	2,632,320	2,733,193
Commitments and contingencies (Note 17)
Redeemable limited partnership units at redemption value;
Redeemable limited partnership units at redemption value; 1,763,739 and 1,845,737 issued and outstanding in 2013 and 2012, respectively	26,241	26,777
Equity:
6.90% Preferred Shares/Units, issued and outstanding- 4,000,000 in 2013 and 2012	96,850	96,850
General Partners' Capital Account	1,815,979	1,666,341
Accumulated other comprehensive loss	(5,001)	(16,452)
Total Brandywine Realty Trust’s equity	1,907,828	1,746,739
Total liabilities and equity	4,566,389	4,506,709
Series E Preferred Stock [Member]
Equity:
Total equity	$ 40	$ 40