Consolidated Statements of Partners' Equity - USD ($) $ in Thousands	Total	BRANDYWINE OPERATING PARTNERSHIP, L.P.	General Partner Capital [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Series E-linked Preferred Stock [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Accumulated Other Comprehensive Loss [Member]	Accumulated Other Comprehensive Loss [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.	Noncontrolling Interest [Member]	Noncontrolling Interest [Member] BRANDYWINE OPERATING PARTNERSHIP, L.P.
Beginning Balance at Dec. 31, 2015		$ 1,929,977	$ 1,836,692	$ 96,850		$ (5,597)		$ 2,032
Beginning Balance, Shares at Dec. 31, 2015			174,688,568	4,000,000
Net income	$ 52,871	52,871	$ 52,859				$ 425	12
Other comprehensive income (loss)	(9,946)	(9,946)			$ (9,860)	(9,946)	(86)
Share Issuance from/(to) Deferred Compensation Plan	(47)	(47)	$ (47)
Share Issuance from/(to) Deferred Compensation Plan, Shares			(8,311)
Issuance of partnership interest in consolidated real estate venture	73	73					73	73
Conversion of LP Units to Common Shares		875	$ 875				(875)
Conversion of LP Units to Common Shares, Shares			55,303
Share-based compensation activity	4,934	4,929	$ 4,929
Share-based compensation activity, Shares			405,200
Adjustment of redeemable partnership units to liquidation value at period end		(1,935)	$ (1,935)
Redemption value of limited partnership units		(875)	(875)
Distribution to preferred shareholders	(5,175)	(5,175)	(5,175)
Preferred Mirror Units redemption charge	0	0
Distributions to general partnership unitholders		(82,524)	(82,524)
Ending Balance at Sep. 30, 2016		1,888,223	$ 1,804,799	$ 96,850		(15,543)		2,117
Ending Balance, Shares at Sep. 30, 2016			175,140,760	4,000,000
Beginning Balance at Dec. 31, 2016		1,859,642	$ 1,762,764	$ 96,850		(2,122)		2,150
Beginning Balance, Shares at Dec. 31, 2016			175,140,760	4,000,000
Net income	48,015	48,015	$ 47,990				384	25
Other comprehensive income (loss)	846	846			$ 839	846	7
Redemption of Preferred Mirror Units		(96,850)		$ (96,850)
Redemption of Preferred Mirror Units, Shares				(4,000,000)
Share Issuance from/(to) Deferred Compensation Plan	(48)	(48)	$ (48)
Share Issuance from/(to) Deferred Compensation Plan, Shares			(1,718)
Issuance of LP Units		(499)	$ (499)
Issuance of partnership interest in consolidated real estate venture	85	86					85	86
Distributions from consolidated real estate venture	(46)	(46)					$ (46)	(46)
Share Choice Plan Issuance, Shares			(1,423)
Bonus share issuance	110	110	$ 110
Bonus share issuance, Shares			6,752
Share-based compensation activity	5,907	5,907	$ 5,907
Share-based compensation activity, Shares			333,127
Adjustment of redeemable partnership units to liquidation value at period end		(2,781)	$ (2,781)
Distribution to preferred shareholders	(2,032)	(2,032)	(2,032)
Preferred Mirror Units redemption charge	$ (3,181)	(3,181)	(3,181)
Distributions to general partnership unitholders		(84,463)	(84,463)
Ending Balance at Sep. 30, 2017		$ 1,724,706	$ 1,723,767			$ (1,276)		$ 2,215
Ending Balance, Shares at Sep. 30, 2017			175,477,498