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