Partners Equity of the Operating Partnership Partners Equity of the Operating Partnership (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)
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 Discontinued Operations	(2,252)	12,712	3,824	30,120
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 units 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 Partnership Unit [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
BRANDYWINE OPERATING PARTNERSHIP, L.P.
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)
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 unitholders, Basic	7,622	(11,144)	3,632	(21,310)
Income (Loss) from continuing operations available to common unitholders, Diluted	7,622	(11,144)	3,632	(21,310)
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
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	5,370	1,568	7,456	8,810
Net Income (Loss) Available to Common Shareholders/unitholders, Diluted	$ 5,370	$ 1,568	$ 7,456	$ 8,810
Denominator
Weighted-average units outstanding, Basic	157,131,697	145,958,358	151,323,813	145,721,890
Contingent securities/Share based compensation	1,343,817	0	1,157,288	0
Weighted Average Number of Shares Outstanding, Diluted	158,475,514	145,958,358	152,481,101	145,721,890
Earnings per Common Partnership Unit [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