Beneficiaries Equity of the Parent Company Beneficiaries Equity of the Parent Company (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)
Net Income (Loss) From Continuing Operations Attributable to Non controlling interests, Basic	(106)	(49)	(147)	335
Net Income (Loss) From Continuing Operations Attributable To Non Controlling Interests, Diluted	(106)	(49)	(147)	335
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 Shareholders/unitholders, Basic	9,258	2,571	12,968	(18,223)
Income (Loss) from Continuing Operations Available to Common Shareholders/unitholders, Diluted	9,258	2,571	12,968	(18,223)
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
Discontinued operations attributable to non-controlling interests, Basic	1	(211)	(48)	(760)
Discontinued Operations Attributable to Noncontrolling Interests- Diluted	1	(211)	(48)	(760)
Discontinued operations attributable to common shareholders, Basic	(85)	11,378	3,571	40,817
Discontinued operations attributable to common shareholders, Diluted	(85)	11,378	3,571	40,817
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 Number of Shares 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 share from continuing operations 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