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, 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
Net (income) loss from continuing operations attributable to non-controlling interests									339	43	(357)
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic									(329)	(349)	(363)
Preferred Share distributions									(6,900)	(6,900)	(6,900)
Income (Loss) from continuing operations available to common Shareholders, Basic									(37,630)	(1,182)	31,362
Income from discontinued operations									0	908	4,152
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust									(37,630)	(274)	35,514
Net income (loss) from continuing operations attributable to non-controlling interests, Diluted									339	43	(357)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted									(329)	(349)	(363)
Income (loss) from continuing operations available to common shareholders, Diluted									(37,630)	(1,182)	31,362
Income (loss) from discontinued operations, Diluted									0	908	4,152
Net income (loss) attributable to common shareholders, Diluted									$ (37,630)	$ (274)	$ 35,514
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 Share:
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