Partners Equity of The Operating Partnership (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)
Amount allocated to unvested restricted shareholders/unitholders, Basic	(95)	(121)	(191)	(263)
Amount allocable to unvested restricted unitholders, 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
Income from discontinued operations	10,949	5,579	26,632	7,415
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
Income per Common Partnership Unit:
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)
Income (Loss) From Discontinued Operations Diluted	10,949	5,579	26,632	7,415
BRANDYWINE OPERATING PARTNERSHIP, L.P.
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)
Amount allocated to unvested restricted shareholders/unitholders, Basic	(95)	(121)	(191)	(263)
Amount allocable to unvested restricted unitholders, 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 unitholders, Basic	(9,381)	(13,932)	(17,822)	(18,398)
Loss from continuing operations available to common unit holders, Diluted	(9,381)	(13,932)	(17,822)	(18,398)
Income from discontinued operations	10,949	5,579	26,632	7,415
Discontinued operations attributable to common unit holders, Diluted	10,949	5,579	26,632	7,415
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	1,568	(8,353)	8,810	(10,983)
Net income (loss) available to common shareholders, Diluted	$ 1,568	$ (8,353)	$ 8,810	$ (10,983)
Denominator
Weighted-average units outstanding, Basic	145,958,358	145,220,765	145,721,890	144,852,515
Weighted-average shares/units outstanding, Diluted	145,958,358	145,220,765	145,721,890	144,852,515
Income per Common Partnership Unit:
Loss from continuing operations attributable to common shareholders/unitholders, Basic	$ (0.06)	$ (0.10)	$ (0.12)	$ (0.13)
Loss from continuing operations attributable to common shareholders/unitholders, Diluted	$ (0.06)	$ (0.10)	$ (0.12)	$ (0.13)
Discontinued operations attributable to common shareholders, Basic	$ 0.07	$ 0.04	$ 0.18	$ 0.05
Discontinued operations attributable to common shareholders, Diluted	$ 0.07	$ 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)