Partners Equity of the Operating Partnership (Details Textuals) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended		12 Months Ended		6 Months Ended		12 Months Ended	6 Months Ended			0 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Feb. 07, 2014	Jun. 30, 2014 BRANDYWINE OPERATING PARTNERSHIP, L.P.	Jun. 30, 2013 BRANDYWINE OPERATING PARTNERSHIP, L.P.	Dec. 31, 2013 BRANDYWINE OPERATING PARTNERSHIP, L.P.	Jun. 30, 2014 6.90% Series E-linked Preferred Units [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Jul. 07, 2014 Dividend Paid [Member]	Jul. 07, 2014 Dividend Paid [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Jul. 15, 2014 Dividend Paid [Member] 6.90% Series E-linked Preferred Units [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	May 29, 2014 Dividend Declared [Member]	May 29, 2014 Dividend Declared [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings per Common Partnership Unit [Line Items]
Dividends Payable, Amount Per Share				$ 0.15								$ 0.15	$ 0.15
Proceeds from Issuance of Common Stock	$ 0	$ 181,527			$ 0	$ 181,527
Distributions payable	25,588		25,584		25,588		25,584		23,600	23,900
Preferred Stock, Dividend Rate, Percentage	6.90%		6.90%		6.90%		6.90%	6.90%
Preferred Stock, Liquidation Preference Per Share								$ 25.00
Dividends, Preferred Stock, Cash	$ 3,450	$ 3,450									$ 1,700