Beneficiaries Equity of the Parent Company (Textual) (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		12 Months Ended
	Mar. 10, 2017	Mar. 01, 2017	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Class of Stock [Line Items]
Dividends, Common Stock		$ 28,300
Preferred Stock, Dividend Rate, Percentage			6.90%		6.90%
Dividends, Preferred Stock			$ 1,725	$ 1,725
Redemption outstanding shares			4,000,000		4,000,000
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage			6.90%		6.90%
Dividends, Preferred Stock			$ 1,725	$ 1,725
Redemption outstanding shares			4,000,000		4,000,000
Series E Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage			6.90%
Preferred Stock, Liquidation Preference Per Share			$ 25.00
Dividends, Preferred Stock		$ 1,700
Redemption outstanding shares	4,000,000
Redemption price per share	$ 25.00
Series E Preferred Stock [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Class of Stock [Line Items]
Redemption outstanding shares	4,000,000
Redemption price per share	$ 25.00
Redemption date	Apr. 11, 2017
Dividend Declared [Member]
Class of Stock [Line Items]
Dividends Payable, Amount Per Share		$ 0.16
Dividend Declared [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Class of Stock [Line Items]
Dividends Payable, Amount Per Share		$ 0.16
Redeemable Common Limited Partnership Units [Member]
Class of Stock [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share			1,479,799	1,535,102