Beneficiaries Equity of The Parent Company (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Numerator
Loss from continuing operations, Basic	$ (4,147)	$ (11,813)	$ (10,494)	$ (14,139)
Loss from continuing operations, Diluted	(4,147)	(11,813)	(10,494)	(14,139)
Net income from continuing operations attributable to non-controlling interests, Basic	169	276	322	364
Net income from continuing operations attributable to non-controlling interests, Diluted	169	276	322	364
Amount allocated to unvested restricted shareholders/unitholders, Basic	(95)	(121)	(191)	(263)
Amount allocable to unvested restricted shareholders, Diluted	(95)	(121)	(191)	(263)
Preferred share dividends, Basic	(3,049)	(1,998)	(5,047)	(3,996)
Preferred share dividends, Diluted	(3,049)	(1,998)	(5,047)	(3,996)
Redemption Premium, Basic	(2,090)	0	(2,090)	0
Redemption Premium, Diluted	(2,090)	0	(2,090)	0
Loss from continuing operations available to common shareholders, Basic	(9,212)	(13,656)	(17,500)	(18,034)
Loss from continuing operations available to common shareholders, Diluted	(9,212)	(13,656)	(17,500)	(18,034)
Income from discontinued operations	10,949	5,579	26,632	7,415
Income (loss) from discontinued operations, Diluted	10,949	5,579	26,632	7,415
Discontinued operations attributable to non-controlling interests - LP units	(200)	(111)	(487)	(148)
Discontinued operations attributable to non-controlling interests, diluted	(200)	(111)	(487)	(148)
Discontinued operations attributable to common shareholders, Basic	10,749	5,468	26,145	7,267
Discontinued operations attributable to common shareholders, Diluted	10,749	5,468	26,145	7,267
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	1,537	(8,188)	8,645	(10,767)
Net income (loss) available to common shareholders, Diluted	$ 1,537	$ (8,188)	$ 8,645	$ (10,767)
Denominator
Weighted-average units outstanding, Basic	143,300,637	135,342,538	143,060,796	134,962,093
Weighted-average shares/units outstanding, Diluted	143,300,637	135,342,538	143,060,796	134,962,093
Earnings per Common Share:
Loss from continuing operations attributable to common shareholders/unitholders, Basic	$ (0.07)	$ (0.10)	$ (0.12)	$ (0.13)
Loss from continuing operations attributable to common shareholders/unitholders, Diluted	$ (0.07)	$ (0.10)	$ (0.12)	$ (0.13)
Discontinued operations attributable to common shareholders, Basic	$ 0.08	$ 0.04	$ 0.18	$ 0.05
Discontinued operations attributable to common shareholders, Diluted	$ 0.08	$ 0.04	$ 0.18	$ 0.05
Net income (loss) attributable to common shareholders/unitholders, Basic	$ 0.01	$ (0.06)	$ 0.06	$ (0.08)
Net income (loss) attributable to common shareholders/unitholders, Diluted	$ 0.01	$ (0.06)	$ 0.06	$ (0.08)