Partners Equity of the Operating Partnership (Textual) (Details) - USD ($)		12 Months Ended
	Dec. 08, 2015	Dec. 31, 2015	Dec. 31, 2014	Jul. 22, 2015	Dec. 31, 2013	Nov. 05, 2013
Earnings Per Common Partnership Unit [Line Items]
Distributions payable		$ 28,249,000	$ 28,871,000
Preferred Stock, Dividend Rate, Percentage		6.90%	6.90%
Shares Authorized For Equity Offering Program						16,000,000
Authorized Amount				$ 100,000,000
Number of Shares Authorized to be Repurchased				539,200
Repurchased and Retired, Shares		5,209,437
Share Price		$ 12.90
Repurchased and Retired, Value		$ 67,325,000
Common Stock, Par or Stated Value Per Share (USD per share)		$ 0.01	$ 0.01
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Distributions payable		$ 28,249,000	$ 28,871,000
Preferred Stock, Dividend Rate, Percentage		6.90%	6.90%
Dividend Declared [Member]
Earnings Per Common Partnership Unit [Line Items]
Dividends Payable, Amount Per Share	$ 0.15
Dividend Declared [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Dividends Payable, Amount Per Share	$ 0.15
Dividend Paid [Member]
Earnings Per Common Partnership Unit [Line Items]
Distributions payable		$ 26,500,000
Dividend Paid [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Distributions payable		$ 26,500,000
Class A Units [Member]
Earnings Per Common Partnership Unit [Line Items]
Redeemable Limited Partnership Units Potential Cash Redemption Value Closing Market Price		$ 13.66	$ 15.98		$ 14.09
Limited Partners' Capital Account, Units Outstanding		1,535,102	1,535,102		1,763,739
6.90% Series E-linked Preferred Units [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Preferred Stock, Dividend Rate, Percentage		6.90%
Preferred Stock, Liquidation Preference Per Share		$ 25.00
6.90% Series E-linked Preferred Units [Member] | Dividend Paid [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Dividends, Preferred Stock, Cash	$ 1,700,000
Offering Program [Member]
Earnings Per Common Partnership Unit [Line Items]
Remaining Shares Available For Sales		16,000,000
Offering Program [Member] | Maximum [Member]
Earnings Per Common Partnership Unit [Line Items]
Fees and Commissions Percentage		2.00%