Consolidated Statements of Partners' Equity - USD ($) $ in Thousands	Total	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]	BRANDYWINE OPERATING PARTNERSHIP, L.P.	BRANDYWINE OPERATING PARTNERSHIP, L.P. General Partner Capital [Member]	BRANDYWINE OPERATING PARTNERSHIP, L.P. Accumulated Other Comprehensive Income (Loss) [Member]	BRANDYWINE OPERATING PARTNERSHIP, L.P. Noncontrolling Interest [Member]	BRANDYWINE OPERATING PARTNERSHIP, L.P. Series E-linked Preferred Stock [Member]
Beginning Balance at Dec. 31, 2016				$ 1,859,642	$ 1,762,764	$ (2,122)	$ 2,150	$ 96,850
Beginning Balance, Shares at Dec. 31, 2016					175,140,760			4,000,000
Net income	$ 21,271		$ 169	21,271	$ 21,266		5
Other comprehensive income	1,300	$ 1,288	12	1,300		1,300
Share Issuance from/(to) Deferred Compensation Plan	(48)			(48)	$ (48)
Share Issuance from/(to) Deferred Compensation Plan, Shares					354
Issuance of LP Units				(219)	$ (219)
Issuance of partnership interest in consolidated real estate venture	29		29	29			29
Share Choice Plan Issuance, Shares					(1,423)
Bonus share issuance	110			110	$ 110
Bonus share issuance, Shares					6,752
Share-based compensation activity	3,770			3,769	$ 3,769
Share-based compensation activity, Shares					56,669
Adjustment of redeemable partnership units to liquidation value at period end				(340)	$ (340)
Preferred Share distributions	(1,725)			(1,725)	(1,725)
Distributions to general partnership unitholders				(28,122)	(28,122)
Ending Balance at Mar. 31, 2017				1,855,667	$ 1,757,455	(822)	2,184	$ 96,850
Ending Balance, Shares at Mar. 31, 2017					175,202,404			4,000,000
Beginning Balance at Dec. 31, 2017				1,819,682	$ 1,815,411	2,056	2,215
Beginning Balance, Shares at Dec. 31, 2017					178,285,236
Net income	44,705		376	44,705	$ 44,700		5
Other comprehensive income	5,008	$ 4,966	42	5,008		5,008
Share Issuance from/(to) Deferred Compensation Plan, Shares					(66,830)
Issuance of LP Units				416	$ 416
Issuance of LP Units, Shares					23,311
Issuance of partnership interest in consolidated real estate venture	15		15	15			15
Distributions from consolidated real estate venture	(54)		$ (54)	(54)			(54)
Share Choice Plan Issuance, Shares					(1,285)
Share-based compensation activity	3,076			3,075	$ 3,075
Share-based compensation activity, Shares					68,425
Adjustment of redeemable partnership units to liquidation value at period end				3,604	$ 3,604
Preferred Share distributions	$ 0			0
Distributions to general partnership unitholders				(32,259)	(32,259)
Ending Balance at Mar. 31, 2018				$ 1,844,192	$ 1,834,947	$ 7,064	$ 2,181
Ending Balance, Shares at Mar. 31, 2018					178,442,517