Partners Equity of The Operating Partnership (DetailsTextuals) (USD $)	9 Months Ended
	Sep. 30, 2011	Oct. 19, 2011	Aug. 05, 2010
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Distribution Declared per common partnership unit		$ 0.15
Net proceeds contributed by Parent Company	$ 8,000,000
Issue of shares under Offering Program	679,285
Market price of shares on acquisition date			11.54
Dividend rate			0.60
Redemption price of partnership unit			Either for an amount, per unit, of cash equal to the market price of one of the Parent Company’s common share (based on the five-day trading average ending on the date of the exchange) or for one of the Parent Company’s common share
BRANDYWINE OPERATING PARTNERSHIP, L.P. | Class F (2010) Units [Member]
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Partnership units issued for acquisition			7,111,112
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Distribution Declared per common partnership unit		$ 0.15
Distribution Declared for common partnership unitholders		20,500,000
Common partnership units issued to the parent company	679,285
7.375% Series E Preferred Shares [Member]
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Distributions paid Preferred unitholders	1,100,000
Percentage of Preferential return	7.375%
7.50% Series D Preferred Shares [Member]
Partners Equity of The Operating Partnership (Textuals) [Abstract]
Distributions paid Preferred unitholders	$ 900,000
Percentage of Preferential return	7.50%