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
	Mar. 31, 2016	Mar. 31, 2015
Numerator
Income from continuing operations	$ 46,310	$ 8,594
Nonforfeitable dividends allocated to unvested restricted shareholders	(105)	(101)
Distribution to preferred shareholders	(1,725)	(1,725)
Net income attributable to Common Share/Unit holders of entity	44,091	6,710
Net income attributable to common share/unit holders, Diluted	$ 44,091	$ 6,710
Denominator
Basic weighted average shares outstanding (in shares)	174,788,945	179,562,930
Contingent securities/Share based compensation (in shares)	682,468	1,092,342
Diluted weighted average shares outstanding (in shares)	175,471,413	180,655,272
Earnings per Common Partnership Unit:
Net income attributable to common shareholders, Basic (USD per share)	$ 0.25	$ 0.04
Net income attributable to common shareholders, Diluted (USD per share)	$ 0.25	$ 0.04
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Income from continuing operations	$ 46,310	$ 8,594
Nonforfeitable dividends allocated to unvested restricted shareholders	(105)	(101)
Distribution to preferred shareholders	(1,725)	(1,725)
Net income attributable to non-controlling interests	(2)	0
Net income attributable to Common Share/Unit holders of entity	44,478	6,768
Net income attributable to common share/unit holders, Diluted	$ 44,478	$ 6,768
Denominator
Basic weighted average shares outstanding (in shares)	176,324,047	181,098,032
Contingent securities/Share based compensation (in shares)	682,468	1,092,342
Diluted weighted average shares outstanding (in shares)	177,006,515	182,190,374
Earnings per Common Partnership Unit:
Net income attributable to common shareholders, Basic (USD per share)	$ 0.25	$ 0.04
Net income attributable to common shareholders, Diluted (USD per share)	$ 0.25	$ 0.04