Beneficiaries Equity of the Parent Company (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Numerator
Income (Loss) from Continuing Operations, Basic	$ (2,237)	$ (2,245)
Income (Loss) From Continuing Operations, Diluted	(2,237)	(2,245)
Net Income (Loss) From Continuing Operations Attributable to Non controlling interests, Basic	44	50
Net Income (Loss) From Continuing Operations Attributable To Non Controlling Interests, Diluted	44	50
Net income attributable to non-controlling interest — partners' share of consolidated real estate ventures	(12)	0
Noncontrolling Interest in Net Income (Loss) Joint Venture Partners, Redeemable, Diluted	12	0
Amount allocated to unvested restricted shareholders/unitholders, Basic	(103)	(108)
Amount allocated to unvested restricted shareholders/unitholders, Diluted	(103)	(108)
Preferred share/unit dividends, Basic	(1,725)	(1,725)
Preferred share/unit dividends, Diluted	(1,725)	(1,725)
Income (Loss) from Continuing Operations Available to Common Shareholders/unitholders, Basic	(4,033)	(4,028)
Income (Loss) from Continuing Operations Available to Common Shareholders/unitholders, Diluted	(4,033)	(4,028)
Income (Loss) from Discontinued Operations	(8)	6,164
Income (Loss) From Discontinued Operations, Diluted	(8)	6,164
Discontinued operations attributable to non-controlling interests, Basic	0	(78)
Discontinued Operations Attributable to Noncontrolling Interests- Diluted	0	(78)
Discontinued operations attributable to common shareholders, Basic	(8)	6,086
Discontinued operations attributable to common shareholders, Diluted	(8)	6,086
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	(4,041)	2,058
Net Income (Loss) Available to Common Shareholders/unitholders, Diluted	$ (4,041)	$ 2,058
Denominator
Weighted Average Number of Shares Outstanding, Basic	156,794,019	143,605,659
Weighted Average Number of Shares Outstanding, Diluted	156,794,019	143,605,659
Earnings per common share from continuing operations Abstract
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Basic Share	$ (0.03)	$ (0.03)
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Diluted Share	$ (0.03)	$ (0.03)
Discontinued Operations attributable to common shareholders/unitholders, Basic	$ 0.00	$ 0.04
Discontinued Operations attributable to common shareholders/unitholders, Diluted	$ 0.00	$ 0.04
Net income (loss) attributable to common shareholders/unitholders, Basic	$ (0.03)	$ 0.01
Net income attributable to common shareholders/unitholders, Diluted	$ (0.03)	$ 0.01