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, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator
Income (Loss) from continuing operations, Basic									$ (30,740)	$ 6,024	$ 38,982
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic									(329)	(349)	(363)
Preferred Share distributions									(6,900)	(6,900)	(6,900)
Income (loss) from discontinued operations, Basic									0	918	4,207
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted									$ (329)	$ (349)	$ (363)
Denominator
Basic weighted average shares outstanding (in shares)									178,162,160	166,202,649	153,140,458
Contingent securities/Share based compensation (in shares)									0	0	1,273,853
Diluted weighted average shares outstanding (in shares)									178,162,160	166,202,649	154,414,311
Earnings (loss) per Common Partnership Unit:
Income (loss) from continuing operations attributable to common shareholders, Basic (USD per share)									$ (0.21)	$ (0.01)	$ 0.20
Discontinued operations attributable to common shareholders, Basic (USD per share)									0	0.01	0.03
Net income (loss) attributable to common shareholders, Basic (USD per share)	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ (0.02)	$ 0.04	$ 0	$ (0.03)	(0.21)	0	0.23
Income (loss) from continuing operations attributable to common shareholders, Dilued (USD per share)									(0.21)	(0.01)	0.20
Discontinued operations attributable to common shareholders, Diluted (USD per share)									0	0.01	0.03
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ (0.02)	$ 0.04	$ 0	$ (0.03)	$ (0.21)	$ 0	$ 0.23
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Income (Loss) from continuing operations, Basic									$ (30,740)	$ 6,024	$ 38,982
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic									(329)	(349)	(363)
Preferred Share distributions									(6,900)	(6,900)	(6,900)
Net loss attributable to non-controlling interests, Basic									3	44	0
Income (loss) from continuing operations available to common unitholders, Basic									(37,966)	(1,181)	31,719
Income (loss) from discontinued operations, Basic									0	918	4,207
Net income (loss) attributable to common unitholders, Basic									(37,966)	(263)	35,926
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted									(329)	(349)	(363)
Net loss attributable to non-controlling interests, Diluted									3	44	0
Income (loss) from continuing operations available to common unitholders, Diluted									(37,966)	(1,181)	31,719
Income (loss) from discontinued operations, diluted									0	918	4,207
Net income attributable to common unitholders, Diluted									$ (37,966)	$ (263)	$ 35,926
Denominator
Basic weighted average shares outstanding (in shares)									179,697,262	167,942,246	154,929,545
Contingent securities/Share based compensation (in shares)									0	0	1,273,853
Diluted weighted average shares outstanding (in shares)									179,697,262	167,942,246	156,203,398
Earnings (loss) per Common Partnership Unit:
Income (loss) from continuing operations attributable to common shareholders, Basic (USD per share)									$ (0.21)	$ (0.01)	$ 0.20
Discontinued operations attributable to common shareholders, Basic (USD per share)									0	0.01	0.03
Net income (loss) attributable to common shareholders, Basic (USD per share)									(0.21)	0	0.23
Income (loss) from continuing operations attributable to common shareholders, Dilued (USD per share)									(0.21)	(0.01)	0.20
Discontinued operations attributable to common shareholders, Diluted (USD per share)									0	0.01	0.03
Net income (loss) attributable to common shareholders, Diluted (USD per share)									$ (0.21)	$ 0	$ 0.23