Partners Equity of The Operating Partnership (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Numerator
Loss from continuing operations, Basic	$ (5,889)	$ (1,567)
Loss from continuing operations, Diluted	(5,889)	(1,567)
Amount allocated to unvested restricted shareholders/unitholders, Basic	(96)	(142)
Amount allocable to unvested restricted unitholders, Diluted	(96)	(142)
Preferred share dividends, Basic	(1,998)	(1,998)
Preferred share dividends, Diluted	(1,998)	(1,998)
Income (loss) from discontinued operations	15,225	1,077
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	7,108	(2,579)
Net income (loss) available to common shareholders, Diluted	7,108	(2,579)
Denominator
Weighted-average units outstanding, Basic	142,820,955	134,577,421
Contingent securities/Stock based compensation	0	0
Weighted-average shares/units outstanding, Diluted	142,820,955	134,577,421
Income per Common Partnership Unit:
Loss from continuing operations attributable to common shareholders/unitholders, Basic	$ (0.05)	$ (0.03)
Loss from continuing operations attributable to common shareholders/unitholders, Diluted	$ (0.05)	$ (0.03)
Discontinued operations attributable to common shareholders, Basic	$ 0.10	$ 0.01
Discontinued operations attributable to common shareholders, Diluted	$ 0.10	$ 0.01
Net income (loss) attributable to common shareholders/unitholders, Basic	$ 0.05	$ (0.02)
Net income (loss) attributable to common shareholders/unitholders, Diluted	$ 0.05	$ (0.02)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Loss from continuing operations, Basic	(5,889)	(1,567)
Loss from continuing operations, Diluted	(5,889)	(1,567)
Amount allocated to unvested restricted shareholders/unitholders, Basic	(96)	(142)
Amount allocable to unvested restricted unitholders, Diluted	(96)	(142)
Preferred share dividends, Basic	(1,998)	(1,998)
Preferred share dividends, Diluted	(1,998)	(1,998)
Loss from continuing operations available to common unitholders, Basic	(7,983)	(3,707)
Loss from continuing operations available to common unit holders, Diluted	(7,983)	(3,707)
Income (loss) from discontinued operations	15,225	1,077
Discontinued operations attributable to common unit holders, Diluted	15,225	1,077
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	7,242	(2,630)
Net income (loss) available to common shareholders, Diluted	$ 7,242	$ (2,630)
Denominator
Weighted-average units outstanding, Basic	145,485,422	144,480,173
Contingent securities/Stock based compensation	0	0
Weighted-average shares/units outstanding, Diluted	145,485,422	144,480,173
Income per Common Partnership Unit:
Loss from continuing operations attributable to common shareholders/unitholders, Basic	$ (0.05)	$ (0.03)
Loss from continuing operations attributable to common shareholders/unitholders, Diluted	$ (0.05)	$ (0.03)
Discontinued operations attributable to common shareholders, Basic	$ 0.10	$ 0.01
Discontinued operations attributable to common shareholders, Diluted	$ 0.10	$ 0.01
Net income (loss) attributable to common shareholders/unitholders, Basic	$ 0.05	$ (0.02)
Net income (loss) attributable to common shareholders/unitholders, Diluted	$ 0.05	$ (0.02)