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
	Mar. 31, 2013	Mar. 31, 2012
Numerator
Income (Loss) from Continuing Operations, Basic	$ (2,003)	$ (7,859)
Income (Loss) From Continuing Operations, Diluted	(2,003)	(7,859)
Amount allocated to unvested restricted shareholders/unitholders, Basic	(108)	(96)
Amount allocated to unvested restricted shareholders/unitholders, Diluted	(108)	(96)
Preferred share/unit dividends, Basic	(1,725)	(1,998)
Preferred share/unit dividends, Diluted	(1,725)	(1,998)
Income (Loss) from Discontinued Operations	5,922	17,195
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	2,058	7,108
Net Income (Loss) Available to Common Shareholders/unitholders, Diluted	2,058	7,108
Denominator
Weighted-average units outstanding, Basic	143,605,659	142,820,955
Weighted average units outstanding, Diluted	143,605,659	142,820,955
Earnings per Common Partnership Unit [Abstract]
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Basic Share	$ (0.03)	$ (0.07)
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Diluted Share	$ (0.03)	$ (0.07)
Discontinued Operations attributable to common shareholders/unitholders, Basic	$ 0.04	$ 0.12
Discontinued Operations attributable to common shareholders/unitholders, Diluted	$ 0.04	$ 0.12
Net income (loss) attributable to common shareholders/unitholders, Basic	$ 0.01	$ 0.05
Net income (loss) attributable to common shareholders/unitholders, Diluted	$ 0.01	$ 0.05
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Income (Loss) from Continuing Operations, Basic	(2,003)	(7,859)
Income (Loss) From Continuing Operations, Diluted	(2,003)	(7,859)
Amount allocated to unvested restricted shareholders/unitholders, Basic	(108)	(96)
Amount allocated to unvested restricted shareholders/unitholders, Diluted	(108)	(96)
Preferred share/unit dividends, Basic	(1,725)	(1,998)
Preferred share/unit dividends, Diluted	(1,725)	(1,998)
Income Loss from continuing operations available to common unitholders, Basic	(3,836)	(9,953)
Income Loss from continuing operations available to common unitholders, Diluted	(3,836)	(9,953)
Income (Loss) from Discontinued Operations	5,922	17,195
Income Loss From Discontinued Operations, Diluted	5,922	17,195
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	2,086	7,242
Net Income (Loss) Available to Common Shareholders/unitholders, Diluted	$ 2,086	$ 7,242
Denominator
Weighted-average units outstanding, Basic	145,451,396	145,485,422
Weighted average units outstanding, Diluted	145,451,396	145,485,422
Earnings per Common Partnership Unit [Abstract]
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Basic Share	$ (0.03)	$ (0.07)
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Diluted Share	$ (0.03)	$ (0.07)
Discontinued Operations attributable to common shareholders/unitholders, Basic	$ 0.04	$ 0.12
Discontinued Operations attributable to common shareholders/unitholders, Diluted	$ 0.04	$ 0.12
Net income (loss) attributable to common shareholders/unitholders, Basic	$ 0.01	$ 0.05
Net income (loss) attributable to common shareholders/unitholders, Diluted	$ 0.01	$ 0.05