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		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator
Income (Loss) from Continuing Operations, Basic	$ 11,174	$ 5,500	$ 18,568	$ (8,350)
Income (Loss) From Continuing Operations, Diluted	11,174	5,500	18,568	(8,350)
Amount allocated to unvested restricted shareholders/unitholders, Basic	(85)	(95)	(278)	(286)
Amount allocated to unvested restricted shareholders/unitholders, Diluted	(85)	(95)	(278)	(286)
Preferred share/unit dividends, Basic	(1,725)	(2,785)	(5,175)	(7,832)
Preferred share/unit dividends, Diluted	(1,725)	(2,785)	(5,175)	(7,832)
Preferred share redemption charge	0	0	0	(2,090)
Redemption Premium, Diluted			0	(2,090)
Income (Loss) from Discontinued Operations	(86)	11,589	3,619	41,577
Net income attributable to Common Shareholders of Brandywine Realty Trust	9,173	13,949	16,539	22,594
Net Income (Loss) Available to Common Shareholders/unitholders, Diluted	9,173	13,949	16,539	22,594
Denominator
Weighted-average units outstanding, Basic	156,703,348	143,424,485	151,933,441	143,182,911
Contingent securities/Share based compensation	1,288,734	703,525	1,209,384	0
Weighted Average Number of Shares Outstanding, Diluted	157,992,082	144,128,010	153,142,825	143,182,911
Earnings per Common Partnership Unit [Abstract]
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Basic Share	$ 0.06	$ 0.02	$ 0.09	$ (0.13)
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Diluted Share	$ 0.06	$ 0.02	$ 0.09	$ (0.13)
Discontinued Operations attributable to common shareholders/unitholders, Basic	$ 0.00	$ 0.08	$ 0.02	$ 0.29
Discontinued Operations attributable to common shareholders/unitholders, Diluted	$ 0.00	$ 0.08	$ 0.02	$ 0.29
Net income (loss) attributable to common shareholders/unitholders, Basic	$ 0.06	$ 0.10	$ 0.11	$ 0.16
Net income attributable to common shareholders/unitholders, Diluted	$ 0.06	$ 0.10	$ 0.11	$ 0.16
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Income (Loss) from Continuing Operations, Basic	11,174	5,500	18,568	(8,350)
Income (Loss) From Continuing Operations, Diluted	11,174	5,500	18,568	(8,350)
Amount allocated to unvested restricted shareholders/unitholders, Basic	(85)	(95)	(278)	(286)
Amount allocated to unvested restricted shareholders/unitholders, Diluted	(85)	(95)	(278)	(286)
Preferred share/unit dividends, Basic	(1,725)	(2,785)	(5,175)	(7,832)
Preferred share/unit dividends, Diluted	(1,725)	(2,785)	(5,175)	(7,832)
Preferred share redemption charge	0	0	0	(2,090)
Redemption Premium, Diluted			0	(2,090)
Income (Loss) from continuing operations available to common unitholders, Basic	9,364	2,620	13,115	(18,558)
Income (Loss) from continuing operations available to common unitholders, Diluted	9,364	2,620	13,115	(18,558)
Income (Loss) from Discontinued Operations	(86)	11,589	3,619	41,577
Income (Loss) From Discontinued Operations, Diluted	(86)	11,589	3,619	41,577
Net income attributable to Common Shareholders of Brandywine Realty Trust	9,278	14,209	16,734	23,019
Net Income (Loss) Available to Common Shareholders/unitholders, Diluted	$ 9,278	$ 14,209	$ 16,734	$ 23,019
Denominator
Weighted-average units outstanding, Basic	158,467,087	146,082,206	153,731,070	145,842,872
Contingent securities/Share based compensation	1,288,734	703,525	1,209,384	0
Weighted Average Number of Shares Outstanding, Diluted	159,755,821	146,785,731	154,940,454	145,842,872
Earnings per Common Partnership Unit [Abstract]
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Basic Share	$ 0.06	$ 0.02	$ 0.09	$ (0.13)
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Diluted Share	$ 0.06	$ 0.02	$ 0.09	$ (0.13)
Discontinued Operations attributable to common shareholders/unitholders, Basic	$ 0.00	$ 0.08	$ 0.02	$ 0.29
Discontinued Operations attributable to common shareholders/unitholders, Diluted	$ 0.00	$ 0.08	$ 0.02	$ 0.29
Net income (loss) attributable to common shareholders/unitholders, Basic	$ 0.06	$ 0.10	$ 0.11	$ 0.16
Net income attributable to common shareholders/unitholders, Diluted	$ 0.06	$ 0.10	$ 0.11	$ 0.16