Partners Equity of The Operating Partnership (DetailsTextuals) (USD $)	3 Months Ended				0 Months Ended	3 Months Ended	0 Months Ended	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Apr. 19, 2012 BRANDYWINE OPERATING PARTNERSHIP, L.P.	Apr. 05, 2012 BRANDYWINE OPERATING PARTNERSHIP, L.P.	Apr. 16, 2012 BRANDYWINE OPERATING PARTNERSHIP, L.P. 7.50% Series D Preferred Shares	Mar. 31, 2012 BRANDYWINE OPERATING PARTNERSHIP, L.P. 7.50% Series D Preferred Shares	Apr. 16, 2012 BRANDYWINE OPERATING PARTNERSHIP, L.P. 7.375% Series E Preferred Shares	Mar. 31, 2012 BRANDYWINE OPERATING PARTNERSHIP, L.P. 7.375% Series E Preferred Shares	Aug. 05, 2010 BRANDYWINE OPERATING PARTNERSHIP, L.P. Class F (2010) Units
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Distribution Declared per common partnership unit			$ 0.15
Dividends Payable, Amount				$ 21,600,000
Percentage of Preferential return						7.50%		7.375%
Dividends, Preferred Stock, Cash	1,998,000	1,998,000			900,000		1,100,000
Partnership units issued for acquisition									7,111,112
Market price of shares on acquisition date									11.54
Dividend rate									$ 0.60