Partners Equity of The Operating Partnership (DetailsTextuals) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended							12 Months Ended				12 Months Ended			0 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Series D Preferred Stock [Member]	Dec. 31, 2012 Series E Preferred Stock [Member]	Dec. 31, 2012 Class A Units [Member]	Dec. 31, 2011 Class A Units [Member]	Dec. 31, 2012 BRANDYWINE OPERATING PARTNERSHIP, L.P.	Dec. 31, 2011 BRANDYWINE OPERATING PARTNERSHIP, L.P.	Dec. 31, 2010 BRANDYWINE OPERATING PARTNERSHIP, L.P.	Dec. 11, 2012 BRANDYWINE OPERATING PARTNERSHIP, L.P.	Dec. 31, 2012 BRANDYWINE OPERATING PARTNERSHIP, L.P. Series D Preferred Stock [Member]	Dec. 31, 2012 BRANDYWINE OPERATING PARTNERSHIP, L.P. Series E Preferred Stock [Member]	Dec. 31, 2012 BRANDYWINE OPERATING PARTNERSHIP, L.P. 6.90% Series E-linked Preferred Units [Member]	Dec. 17, 2012 General Partner [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Dec. 31, 2012 General Partner [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Dec. 31, 2011 General Partner [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Dec. 31, 2010 General Partner [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Dec. 31, 2012 Series C Preferred Stock [Member]	Dec. 31, 2011 Series C Preferred Stock [Member]	Dec. 31, 2012 Series D Preferred Stock [Member]	Dec. 31, 2011 Series D Preferred Stock [Member]	Dec. 31, 2012 Series E Preferred Stock [Member]	Dec. 31, 2012 Series E Preferred Stock [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Dec. 31, 2011 Series E Preferred Stock [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Redemption Premium	$ 4,052	$ 0	$ 0	$ (2,000)				$ 4,052	$ 0	$ 0		$ (2,100)	$ (2,000)			$ 4,052
Distribution Declared per common partnership unit											$ 0.15
Dividends Payable, Amount	23,652	23,895						23,652	23,895		21,600
Percentage of Preferential return					6.90%			6.90%	0.00%					6.90%					0.00%	7.50%	0.00%	7.375%	6.90%	0.00%	7.375%
Dividends, Preferred Stock, Cash	10,405	7,992	7,992		1,700									1,800		10,405	7,992	7,992
Redeemable Limited Partnership Units Potential Cash Redemption Value Closing Market Price	$ 12.19	$ 9.50	$ 11.65
Limited Partners' Capital Account, Units Outstanding						1,845,737	2,698,647
Partners' Capital Account, Redemptions	$ (9,741)														$ 9,700	$ (9,741)
Partners' Capital Account, Units, Redeemed															811,984
Partners' Capital, Redemption and Conversion Policies															$ 12.00