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								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator
Income (Loss) from continuing operations, Basic									$ 40,501	$ (30,740)	$ 6,024
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic									(341)	(329)	(349)
Distribution to preferred shareholders									(6,900)	(6,900)	(6,900)
Income (loss) from discontinued operations, Basic									0	0	918
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted									$ (341)	$ (329)	$ (349)
Denominator
Basic weighted average shares outstanding (in shares)									175,018,163	178,162,160	166,202,649
Contingent securities/Share based compensation (in shares)									992,651	0	0
Diluted weighted average shares outstanding (in shares)									176,010,814	178,162,160	166,202,649
Earnings (loss) per Common Share:
Income (loss) from continuing operations attributable to common shareholders, Basic (USD per share)									$ 0.19	$ (0.21)	$ (0.01)
Discontinued operations attributable to common shareholders, Basic (USD per share)									0	0	0.01
Net income (loss) attributable to common shareholders, Basic (USD per share)	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	0.19	(0.21)	0
Income (loss) from continuing operations attributable to common shareholders, Diluted (USD per share)									0.19	(0.21)	(0.01)
Discontinued operations attributable to common shareholders, Diluted (USD per share)									0	0	0.01
Net income (loss) attributable to common shareholders, Diluted (USD per share)	(0.08)	0.03	(0.02)	0.25	(0.37)	0.10	0.01	0.04	$ 0.19	$ (0.21)	$ 0
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Income (Loss) from continuing operations, Basic									$ 40,501	$ (30,740)	$ 6,024
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic									(341)	(329)	(349)
Distribution to preferred shareholders									(6,900)	(6,900)	(6,900)
Net (income) loss attributable to non-controlling interests									(15)	3	44
Income (loss) from continuing operations available to common unitholders, Basic									33,245	(37,966)	(1,181)
Income (loss) from discontinued operations, Basic									0	0	918
Net income (loss) attributable to common unitholders, Basic									33,245	(37,966)	(263)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted									(341)	(329)	(349)
Income (loss) from continuing operations available to common unitholders, Diluted									33,245	(37,966)	(1,181)
Income (loss) from discontinued operations, diluted									0	0	918
Net income attributable to common unitholders, Diluted									$ 33,245	$ (37,966)	$ (263)
Denominator
Basic weighted average shares outstanding (in shares)									176,523,800	179,697,262	167,942,246
Contingent securities/Share based compensation (in shares)									992,651	0	0
Diluted weighted average shares outstanding (in shares)									177,516,451	179,697,262	167,942,246
Earnings (loss) per Common Share:
Income (loss) from continuing operations attributable to common shareholders, Basic (USD per share)									$ 0.19	$ (0.21)	$ (0.01)
Discontinued operations attributable to common shareholders, Basic (USD per share)									0	0	0.01
Net income (loss) attributable to common shareholders, Basic (USD per share)	(0.08)	0.03	(0.02)	0.25	(0.36)	0.10	0.04	0.04	0.19	(0.21)	0
Income (loss) from continuing operations attributable to common shareholders, Diluted (USD per share)									0.19	(0.21)	(0.01)
Discontinued operations attributable to common shareholders, Diluted (USD per share)									0	0	0.01
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.36)	$ 0.10	$ 0.04	$ 0.04	$ 0.19	$ (0.21)	$ 0