Beneficiaries Equity of the Parent Company - Number of Shares and Net Income Used to Calculate Basic and Diluted Earnings per Share (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
Net (income) loss from continuing operations attributable to non-controlling interests - consolidated real estate ventures									(310)	339	43
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic									(341)	(329)	(349)
Preferred Share distributions									(6,900)	(6,900)	(6,900)
Income (Loss) from continuing operations available to common Shareholders, Basic									32,950	(37,630)	(1,182)
Income from discontinued operations									0	0	908
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust									32,950	(37,630)	(274)
Net income (loss) from continuing operations attributable to non-controlling interests, Diluted									(310)	339	43
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted									(341)	(329)	(349)
Income (loss) from continuing operations available to common shareholders, Diluted									32,950	(37,630)	(1,182)
Income (loss) from discontinued operations, Diluted									0	0	908
Net income (loss) attributable to common shareholders, Diluted									$ 32,950	$ (37,630)	$ (274)
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