Partners Equity of the Operating Partnership (Textual) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	12 Months Ended
	Mar. 01, 2017	Mar. 31, 2017	Dec. 31, 2016	Mar. 10, 2017	Mar. 31, 2016
Earnings Per Common Partnership Unit [Line Items]
Distributions payable		$ 30,047	$ 30,032		$ 28,278
Preferred Stock, Dividend Rate, Percentage		6.90%	6.90%
Preferred Stock, Shares Outstanding		4,000,000	4,000,000
Series E Preferred Stock [Member]
Earnings Per Common Partnership Unit [Line Items]
Preferred Stock, Dividend Rate, Percentage		6.90%
Preferred Stock, Liquidation Preference Per Share		$ 25.00
Preferred Stock, Shares Outstanding				4,000,000
Redemption price per share				$ 25.00
Dividend Declared [Member]
Earnings Per Common Partnership Unit [Line Items]
Dividends Payable, Amount Per Share	$ 0.16
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Distributions payable		$ 30,047	$ 30,032		$ 28,278
Preferred Stock, Dividend Rate, Percentage		6.90%	6.90%
Preferred Stock, Shares Outstanding		4,000,000	4,000,000
BRANDYWINE OPERATING PARTNERSHIP, L.P. | 6.90% Series E-linked Preferred Units [Member]
Earnings Per Common Partnership Unit [Line Items]
Preferred Stock, Dividend Rate, Percentage		6.90%
Preferred Stock, Liquidation Preference Per Share		$ 25.00
BRANDYWINE OPERATING PARTNERSHIP, L.P. | Series E Preferred Stock [Member]
Earnings Per Common Partnership Unit [Line Items]
Preferred Stock, Shares Outstanding				4,000,000
Redemption price per share				$ 25.00
BRANDYWINE OPERATING PARTNERSHIP, L.P. | Dividend Declared [Member]
Earnings Per Common Partnership Unit [Line Items]
Dividends Payable, Amount Per Share	$ 0.16
BRANDYWINE OPERATING PARTNERSHIP, L.P. | Dividend Paid [Member]
Earnings Per Common Partnership Unit [Line Items]
Distributions payable		$ 28,300
BRANDYWINE OPERATING PARTNERSHIP, L.P. | Dividend Paid [Member] | 6.90% Series E-linked Preferred Units [Member]
Earnings Per Common Partnership Unit [Line Items]
Dividends, Preferred Stock, Cash	$ 1,700