Partners Equity of the Operating Partnership (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Numerator
Income (Loss) from Continuing Operations, Basic	$ 1,245	$ 9,310	$ (992)	$ 7,065
Income (Loss) From Continuing Operations, Diluted	1,245	9,310	(992)	7,065
Amount allocated to unvested restricted shareholders/unitholders, Basic	(83)	(85)	(186)	(193)
Amount allocated to unvested restricted shareholders/unitholders, Diluted	(83)	(85)	(186)	(193)
Preferred share/unit dividends, Basic	(1,725)	(1,725)	(3,450)	(3,450)
Preferred share/unit dividends, Diluted	(1,725)	(1,725)	(3,450)	(3,450)
Net income attributable to non-controlling interest — partners' share of consolidated real estate ventures	24	0	12	0
Noncontrolling Interest in Net Income (Loss) Joint Venture Partners, Redeemable, Diluted	(24)	0	(12)	0
Income (Loss) from continuing operations available to common unitholders, Basic	(534)	7,413	(4,567)	3,385
Income (Loss) from continuing operations available to common unitholders, Diluted	(534)	7,413	(4,567)	3,385
Income (Loss) from Discontinued Operations	929	(2,130)	921	4,034
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	385	5,308	(3,656)	7,366
Net Income (Loss) Available to Common Shareholders/unitholders, Diluted	385	5,308	(3,656)	7,366
Denominator
Weighted-average units outstanding, Basic	157,037,348	155,347,384	156,916,356	149,508,957
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	0	1,343,817	0	1,157,288
Weighted Average Number of Shares Outstanding, Diluted	157,037,348	156,691,201	156,916,356	150,666,245
Earnings per Common Partnership Unit [Abstract]
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Basic Share	$ 0.00	$ 0.05	$ (0.03)	$ 0.02
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Diluted Share	$ 0.00	$ 0.05	$ (0.03)	$ 0.02
Discontinued Operations attributable to common shareholders/unitholders, Basic	$ 0.00	$ (0.02)	$ 0.01	$ 0.03
Discontinued Operations attributable to common shareholders/unitholders, Diluted	$ 0.00	$ (0.02)	$ 0.01	$ 0.03
Net income (loss) attributable to common shareholders/unitholders, Basic	$ 0.00	$ 0.03	$ (0.02)	$ 0.05
Net income attributable to common shareholders/unitholders, Diluted	$ 0.00	$ 0.03	$ (0.02)	$ 0.05
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Income (Loss) from Continuing Operations, Basic	1,245	9,310	(992)	7,065
Income (Loss) From Continuing Operations, Diluted	1,245	9,310	(992)	7,065
Amount allocated to unvested restricted shareholders/unitholders, Basic	(83)	(85)	(186)	(193)
Amount allocated to unvested restricted shareholders/unitholders, Diluted	(83)	(85)	(186)	(193)
Preferred share/unit dividends, Basic	(1,725)	(1,725)	(3,450)	(3,450)
Preferred share/unit dividends, Diluted	(1,725)	(1,725)	(3,450)	(3,450)
Net income attributable to non-controlling interest — partners' share of consolidated real estate ventures	24	0	12	0
Noncontrolling Interest in Net Income (Loss) Joint Venture Partners, Redeemable, Diluted	(24)	0	(12)	0
Income (Loss) from continuing operations available to common unitholders, Basic	(539)	7,500	(4,616)	3,422
Income (Loss) from continuing operations available to common unitholders, Diluted	(539)	7,500	(4,616)	3,422
Income (Loss) from Discontinued Operations	929	(2,130)	921	4,034
Income (Loss) From Discontinued Operations, Diluted	929	(2,130)	921	4,034
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	390	5,370	(3,695)	7,456
Net Income (Loss) Available to Common Shareholders/unitholders, Diluted	$ 390	$ 5,370	$ (3,695)	$ 7,456
Denominator
Weighted-average units outstanding, Basic	158,801,087	157,131,697	158,680,095	151,323,813
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	0	1,343,817	0	1,157,288
Weighted Average Number of Shares Outstanding, Diluted	158,801,087	158,475,514	158,680,095	152,481,101
Earnings per Common Partnership Unit [Abstract]
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Basic Share	$ 0.00	$ 0.05	$ (0.03)	$ 0.02
Income (Loss) from Continuing Operations Attributable to Common Shareholders/unitholders, Per Diluted Share	$ 0.00	$ 0.05	$ (0.03)	$ 0.02
Discontinued Operations attributable to common shareholders/unitholders, Basic	$ 0.00	$ (0.02)	$ 0.01	$ 0.03
Discontinued Operations attributable to common shareholders/unitholders, Diluted	$ 0.00	$ (0.02)	$ 0.01	$ 0.03
Net income (loss) attributable to common shareholders/unitholders, Basic	$ 0.00	$ 0.03	$ (0.02)	$ 0.05
Net income attributable to common shareholders/unitholders, Diluted	$ 0.00	$ 0.03	$ (0.02)	$ 0.05