Beneficiaries Equity of the Parent Company (Textual) (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		9 Months Ended
	Sep. 12, 2017	Apr. 11, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Class of Stock [Line Items]
Dividends, Common Stock	$ 28,400
Preferred share redemption charge			$ 0	$ 0	$ 3,181	$ 0
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Class of Stock [Line Items]
Dividends, Common Stock	$ 28,400
Preferred share redemption charge			$ 0	$ 0	$ 3,181	$ 0
BRANDYWINE OPERATING PARTNERSHIP, L.P. | Series E Preferred Stock [Member]
Class of Stock [Line Items]
Redemption outstanding shares		4,000,000
Redemption price per share		$ 25.51
Accrued dividends paid in cash		$ 2,000
Preferred share redemption charge		$ 3,200
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	1,479,799