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, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator
Net income	$ 13,136	$ 7,698	$ 57,841	$ 28,969
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(86)	(73)	(200)	(172)
Distribution to preferred shareholders	0	(307)	0	(2,032)
Preferred share redemption charge	0	(3,181)	0	(3,181)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	$ (86)	$ (73)	$ (200)	$ (172)
Denominator
Basic weighted average shares outstanding (in shares)	178,547,555	175,333,300	178,471,960	175,255,564
Contingent securities/Share based compensation (in shares)	1,144,781	1,423,298	1,268,730	1,224,816
Diluted weighted average shares outstanding (in shares)	179,692,336	176,756,598	179,740,690	176,480,380
Earnings per Common Partnership Unit:
Net income attributable to common shareholders, Basic (USD per share)	$ 0.07	$ 0.02	$ 0.32	$ 0.13
Net income attributable to common shareholders, Diluted (USD per share)	$ 0.07	$ 0.02	$ 0.32	$ 0.13
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Net income	$ 13,136	$ 7,698	$ 57,841	$ 28,969
Net income attributable to noncontrolling interests	(21)	(8)	(26)	(13)
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(86)	(73)	(200)	(172)
Distribution to preferred shareholders	0	(307)	0	(2,032)
Preferred share redemption charge	0	(3,181)	0	(3,181)
Net income attributable to common unitholders, Basic	13,029	4,129	57,615	23,571
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	(86)	(73)	(200)	(172)
Net income attributable to common unitholders, Diluted	$ 13,029	$ 4,129	$ 57,615	$ 23,571
Denominator
Basic weighted average shares outstanding (in shares)	180,027,354	176,813,099	179,951,759	176,735,363
Contingent securities/Share based compensation (in shares)	1,144,781	1,423,298	1,268,730	1,224,816
Diluted weighted average shares outstanding (in shares)	181,172,135	178,236,397	181,220,489	177,960,179
Earnings per Common Partnership Unit:
Net income attributable to common shareholders, Basic (USD per share)	$ 0.07	$ 0.02	$ 0.32	$ 0.13
Net income attributable to common shareholders, Diluted (USD per share)	$ 0.07	$ 0.02	$ 0.32	$ 0.13