Beneficiaries Equity of the Parent Company Beneficiaries Equity of the Parent Company (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Numerator
Income (Loss) from Continuing Operations, Basic	$ 9,432	$ (5,910)	$ 7,275	$ (13,982)
Income (Loss) From Continuing Operations, Diluted	9,432	(5,910)	7,275	(13,982)
Net Income (Loss) From Continuing Operations Attributable to Non controlling interests, Basic	(88)	201	(39)	386
Net Income (Loss) From Continuing Operations Attributable To Non Controlling Interests, Diluted	(88)	201	(39)	386
Amount allocated to unvested restricted shareholders/unitholders, Basic	(85)	(95)	(193)	(191)
Amount allocated to unvested restricted shareholders/unitholders, Diluted	(85)	(95)	(193)	(191)
Preferred share/unit dividends, Basic	(1,725)	(3,049)	(3,450)	(5,047)
Preferred share/unit dividends, Diluted	(1,725)	(3,049)	(3,450)	(5,047)
Redemption Premium	0	(2,090)	0	(2,090)
Redemption Premium, Diluted	0	(2,090)	0	(2,090)
Income (Loss) from Continuing Operations Available to Common Shareholders/unitholders, Basic	7,534	(10,943)	3,593	(20,924)
Income (Loss) from Continuing Operations Available to Common Shareholders/unitholders, Diluted	7,534	(10,943)	3,593	(20,924)
Income (Loss) from Discontinued Operations	(2,252)	12,712	3,824	30,120
Income (Loss) From Discontinued Operations, Diluted	(2,252)	12,712	3,824	30,120
Discontinued operations attributable to non-controlling interests, Basic	26	(232)	(51)	(551)
Discontinued Operations Attributable to Noncontrolling Interests- Diluted	26	(232)	(51)	(551)
Discontinued operations attributable to common shareholders, Basic	(2,226)	12,480	3,773	29,569
Discontinued operations attributable to common shareholders, Diluted	(2,226)	12,480	3,773	29,569
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	5,308	1,537	7,366	8,645
Net Income (Loss) Available to Common Shareholders/unitholders, Diluted	$ 5,308	$ 1,537	$ 7,366	$ 8,645
Denominator
Weighted Average Number of Shares Outstanding, Basic	155,347,384	143,300,637	149,508,957	143,060,796
Contingent securities/Share based compensation	1,343,817	0	1,157,288	0
Weighted Average Number of Shares Outstanding, Diluted	156,691,201	143,300,637	150,666,245	143,060,796
Earnings per common share from continuing operations Abstract
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Basic Share	$ 0.05	$ (0.08)	$ 0.02	$ (0.15)
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Diluted Share	$ 0.05	$ (0.08)	$ 0.02	$ (0.15)
Discontinued Operations attributable to common shareholders/unitholders, Basic	$ (0.02)	$ 0.09	$ 0.03	$ 0.21
Discontinued Operations attributable to common shareholders/unitholders, Diluted	$ (0.02)	$ 0.09	$ 0.03	$ 0.21
Net income (loss) attributable to common shareholders/unitholders, Basic	$ 0.03	$ 0.01	$ 0.05	$ 0.06
Net income (loss) attributable to common shareholders/unitholders, Diluted	$ 0.03	$ 0.01	$ 0.05	$ 0.06