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		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator
Income from continuing operations	$ 7,884	$ 20,308	$ 52,871	$ 31,960
Nonforfeitable dividends allocated to unvested restricted shareholders	(79)	(76)	(263)	(253)
Distribution to preferred shareholders	(1,725)	(1,725)	(5,175)	(5,175)
Net income attributable to Common Share/Unit holders of entity	6,022	18,346	47,008	26,311
Net income attributable to common share/unit holders, Diluted	$ 6,022	$ 18,346	$ 47,008	$ 26,311
Denominator
Basic weighted average shares outstanding (in shares)	175,127,110	178,188,037	174,976,998	179,198,714
Contingent securities/Share based compensation (in shares)	1,237,505	588,647	1,032,824	789,778
Diluted weighted average shares outstanding (in shares)	176,364,615	178,776,684	176,009,822	179,988,492
Earnings per Common Partnership Unit:
Net income attributable to common shareholders, Basic (USD per share)	$ 0.03	$ 0.10	$ 0.27	$ 0.15
Net income attributable to common shareholders, Diluted (USD per share)	$ 0.03	$ 0.10	$ 0.27	$ 0.15
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Income from continuing operations	$ 7,884	$ 20,308	$ 52,871	$ 31,960
Nonforfeitable dividends allocated to unvested restricted shareholders	(79)	(76)	(263)	(253)
Distribution to preferred shareholders	(1,725)	(1,725)	(5,175)	(5,175)
Net (income) loss attributable to non-controlling interests	(6)	(1)	(12)	4
Net income attributable to Common Share/Unit holders of entity	6,074	18,506	47,421	26,536
Net income attributable to common share/unit holders, Diluted	$ 6,074	$ 18,506	$ 47,421	$ 26,536
Denominator
Basic weighted average shares outstanding (in shares)	176,606,909	179,723,139	176,491,311	180,733,816
Contingent securities/Share based compensation (in shares)	1,237,505	588,647	1,032,824	789,778
Diluted weighted average shares outstanding (in shares)	177,844,414	180,311,786	177,524,135	181,523,594
Earnings per Common Partnership Unit:
Net income attributable to common shareholders, Basic (USD per share)	$ 0.03	$ 0.10	$ 0.27	$ 0.15
Net income attributable to common shareholders, Diluted (USD per share)	$ 0.03	$ 0.10	$ 0.27	$ 0.15