Consolidated Statement of Partners' Equity (USD $) In Thousands, except Share data	Total	BRANDYWINE OPERATING PARTNERSHIP, L.P.	Series C Preferred Stock [Member]	Series D Preferred Stock [Member]	Series D Preferred Stock [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Series E Preferred Stock [Member]	Series E Preferred Stock [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Series E-linked Preferred Stock [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	General Partner [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Other Comprehensive Income (Loss) [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Noncontrolling Interest [Member]	Noncontrolling Interest [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Total partners equity [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.
Beginning Balance at Dec. 31, 2009	$ 1,921,740				$ 47,912	$ 43	$ 55,538	$ 0	$ 1,783,033	$ (9,138)	$ (9,428)	$ 38,308	$ 65
Beginning Balance, shares at Dec. 31, 2009					2,000,000	4,300,000	2,300,000	0	128,597,412
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(17,606)	(17,606)							(17,606)			(532)		(17,606)
Other Comprehensive Income (Loss), Net of Tax	7,348	7,348								7,193	7,348	155		7,348
Deferred Compensation Obligation Shares									(2,409)
Deferred Compensation Obligation									0					0
Issuance of LP Units									71,981					71,981
Issuance of LP Units Shares									5,742,268
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	(1,214)
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	369								369					369
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures									32,607
Stock Issued During Period, Value, Conversion of Units	0								466			(466)		466
Stock Issued During Period, Shares, Conversion of Units									17,468
Stock Issued During Period, Value, Restricted Stock Award, Gross	(227)								(227)					(227)
Stock Issued During Period, Shares, Restricted Stock Award, Gross									76,598
Restricted Stock Amortization	3,483								3,483					3,483
Restricted Performance Units Amortization	965								965					965
Outperformance Plan Amortization	380								380					380
Amortization of ESOP Award	1,131								1,132					1,132
Trustee Fees Paid in Shares									98					98
Trustee fees paid in shares units									8,412
Stock Issued During Period, Value, Stock Options Exercised	37								37					37
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	12,761								12,761
Adjustment of Redeemable Partnership Units to Liquidation Value at Period End									(13,839)					(13,839)
Adjustment to Non-controlling Interest													(27)	(27)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	1,401								1,439			(38)	(38)	1,401
Dividends, Preferred Stock, Cash	(7,992)								(7,992)					(7,992)
Preferred share redemption charge	0	0
Partners' Capital Account, Distributions									(80,170)					(80,170)
Ending Balance at Dec. 31, 2010	1,977,774				47,912	43	55,538	0	1,743,549	(1,945)	(2,080)	128,272	0	1,844,919
Ending Balance, shares at Dec. 31, 2010					2,000,000	4,300,000	2,300,000	0	134,485,117
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(4,715)	(4,715)							(4,715)			(215)		(4,715)
Other Comprehensive Income (Loss), Net of Tax	(4,346)	(4,346)								(4,134)	(4,346)	(212)		(4,346)
Deferred Compensation Obligation Shares									(845)
Deferred Compensation Obligation									(16)					(16)
Issuance of LP Units									8,272					8,272
Issuance of LP Units Shares									679,285
Preferred Stock, Value, Issued			20	23		0	55,538	0
Preferred Stock, Shares Issued		0	2,000,000	2,300,000			2,300,000
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	(377)											(32)
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	6								6					6
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures									463
Stock Issued During Period, Value, Conversion of Units	0								86,038			(86,038)		86,038
Stock Issued During Period, Shares, Conversion of Units									7,204,104
Share Choice Plan Issuance Value	55								55					(55)
Share Choice Plan Issuance Shares									(1,684)
Stock Issued During Period, Value, Restricted Stock Award, Gross	(350)								(352)					(352)
Stock Issued During Period, Shares, Restricted Stock Award, Gross									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
Amortization of ESOP Award	1,487								1,487					1,487
Trustee Fees Paid in Shares									32					32
Trustee fees paid in shares units									2,672
Stock Issued During Period, Value, Stock Options Exercised	350								350					350
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	120,180								120,179
Adjustment of Redeemable Partnership Units to Liquidation Value at Period End									5,778					5,778
Dividends, Preferred Stock, Cash	(7,992)								(7,992)					(7,992)
Preferred share redemption charge	0	0
Partners' Capital Account, Distributions									(82,819)					(82,819)
Ending Balance at Dec. 31, 2011	1,889,696							0	1,754,302	(6,079)	(6,426)	33,105	0	1,851,326
Ending Balance, shares at Dec. 31, 2011								0	142,690,755
Beginning Balance at Sep. 30, 2011
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(4,602)
Preferred Stock, Value, Issued			20	23		0	55,538	0
Preferred Stock, Shares Issued			2,000,000	2,300,000			2,300,000
Ending Balance at Dec. 31, 2011	1,889,696				47,912	43	55,538	0	1,754,302	(6,079)	(6,426)	33,105	0	1,851,326
Ending Balance, shares at Dec. 31, 2011					2,000,000	4,300,000	2,300,000	0	142,690,755
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	6,529	6,529							6,529			(66)		6,529
Other Comprehensive Income (Loss), Net of Tax	(10,026)	(10,026)								(9,839)	(10,026)	(187)		(10,026)
Deferred Compensation Obligation Shares									(5,564)
Deferred Compensation Obligation									0					0
Preferred Stock, Value, Issued	96,850		0	0		40	0	96,850						96,850
Preferred Stock, Shares Issued		4,000,000	0	0		4,000,000	0	4,000,000
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	(613)								(613)					(613)
Stock Redeemed or Called During Period, Value	(103,448)				(47,912)	(43)	(55,538)							(103,450)
Stock Redeemed or Called During Period, Shares					(2,000,000)	(4,300,000)	(2,300,000)
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	387								387					387
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures									35,703
Stock Issued During Period, Value, Conversion of Units	(167)								(49)			(268)		(49)
Stock Issued During Period, Shares, Conversion of Units									20,464
Partners' Capital Account, Redemptions	9,741								9,741			5,556		9,741
Stock Issued During Period, Value, Restricted Stock Award, Gross	(1,385)								(1,385)					(1,385)
Stock Issued During Period, Shares, Restricted Stock Award, Gross									293,614
Restricted Stock Amortization	3,271								3,271					3,271
Restricted Stock Award, Forfeitures	35								35					35
Stock Issued During Period, Value, Vesting of restricted performance units	(1,495)								(1,495)					(1,495)
Stock Issued During Period, Shares, Vesting of restricted performance units									272,131
Restricted Performance Units Amortization	3,379								3,379					3,379
Amortization of ESOP Award	1,636								1,636					1,636
Trustee Fees Paid in Shares									15					15
Trustee fees paid in shares units									1,336
Stock Issued During Period, Value, Stock Options Exercised	976								976					976
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	230,294								230,294
Adjustment of Redeemable Partnership Units to Liquidation Value at Period End									9,968					9,968
Dividends, Preferred Stock, Cash	(10,405)								(10,405)					(10,405)
Preferred share redemption charge	(4,052)	(4,052)							(4,052)					(4,052)
Partners' Capital Account, Distributions									(86,417)					(86,417)
Ending Balance at Dec. 31, 2012	1,773,516				0	40	0	96,850	1,666,341	(15,918)	(16,452)	21,238	0	1,746,739
Ending Balance, shares at Dec. 31, 2012					0	4,000,000	0	4,000,000	143,538,733
Beginning Balance at Sep. 30, 2012
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(26,698)
Preferred Stock, Value, Issued	96,850		0	0				96,850
Preferred Stock, Shares Issued			0	0				4,000,000
Ending Balance at Dec. 31, 2012	$ 1,773,516							$ 96,850					$ 0
Ending Balance, shares at Dec. 31, 2012								4,000,000