Partners Equity of the Operating Partnership - Number of Units and Net Income Used to Calculate Basic and Diluted Earnings Per Common Partnership Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator
Income (loss) from continuing operations, Basic	$ 7,698	$ (1,323)	$ 28,969	$ 44,987
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(73)	(79)	(172)	(184)
Distribution to preferred shareholders	(307)	(1,725)	(2,032)	(3,450)
Preferred share redemption charge	(3,181)	0	(3,181)	0
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	$ (73)	$ (79)	$ (172)	$ (184)
Denominator
Basic weighted average shares outstanding (in shares)	175,333,300	175,013,291	175,255,564	174,901,118
Contingent securities/Share based compensation (in shares)	1,423,298	0	1,224,816	922,852
Diluted weighted average shares outstanding (in shares)	176,756,598	175,013,291	176,480,380	175,823,970
Earnings per Common Partnership Unit
Net income (loss) attributable to common unitholders, Basic (USD per share)	$ 0.02	$ (0.02)	$ 0.13	$ 0.23
Net income (loss) attributable to common unitholders, Diluted (USD per share)	$ 0.02	$ (0.02)	$ 0.13	$ 0.23
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Income (loss) from continuing operations, Basic	$ 7,698	$ (1,323)	$ 28,969	$ 44,987
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(73)	(79)	(172)	(184)
Distribution to preferred shareholders	(307)	(1,725)	(2,032)	(3,450)
Preferred share redemption charge	(3,181)	0	(3,181)	0
Net income attributable to non-controlling interests	(8)	(4)	(13)	(6)
Net income (loss) attributable to common unitholders, Basic	4,129	(3,131)	23,571	41,347
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	(73)	(79)	(172)	(184)
Net income (loss) attributable to common unitholders, Diluted	$ 4,129	$ (3,131)	$ 23,571	$ 41,347
Denominator
Basic weighted average shares outstanding (in shares)	176,813,099	176,541,708	176,735,363	176,432,877
Contingent securities/Share based compensation (in shares)	1,423,298	0	1,224,816	922,853
Diluted weighted average shares outstanding (in shares)	178,236,397	176,541,708	177,960,179	177,355,730
Earnings per Common Partnership Unit
Net income (loss) attributable to common unitholders, Basic (USD per share)	$ 0.02	$ (0.02)	$ 0.13	$ 0.23
Net income (loss) attributable to common unitholders, Diluted (USD per share)	$ 0.02	$ (0.02)	$ 0.13	$ 0.23