Beneficiaries Equity of the Parent Company (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Numerator
Income (Loss) from continuing operations, Basic	$ 20,308	$ 8,885	$ 31,960	$ 7,893
Income (Loss) from continuing operations, Diluted	20,308	8,885	31,960	7,893
Net income from continuing operations attributable to non-controlling interests, Basic	(161)	(108)	(221)	(47)
Net income from continuing operations attributable to non-controlling interests, Diluted	(161)	(108)	(221)	(47)
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(76)	(82)	(253)	(268)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	(76)	(82)	(253)	(268)
Preferred share/unit dividends, Basic	(1,725)	(1,725)	(5,175)	(5,175)
Preferred share/unit dividends, Diluted	(1,725)	(1,725)	(5,175)	(5,175)
Income (Loss) from continuing operations available to common unitholders, Basic	18,346	6,970	26,311	2,403
Income (Loss) from continuing operations available to common unitholders, Diluted	18,346	6,970	26,311	2,403
Income (loss) from discontinued operations, Basic	0	(3)	0	918
Income (loss) from discontinued operations, Diluted	0	(3)	0	918
Discontinued operations attributable to non-controlling interests, basic	0	0	0	(10)
Discontinued operations attributable to common shareholders, diluted			0	(10)
Discontinued operations attributable to common shareholders, Basic			0	908
Discontinued operations attributable to common shareholders, Diluted			0	908
Net income attributable to Common Shareholders of Brandywine Realty Trust	18,346	6,967	26,311	3,311
Net income attributable to common shareholders, diluted	$ 18,346	$ 6,967	$ 26,311	$ 3,311
Denominator
Basic weighted average shares outstanding (in shares)	178,188,037	171,606,722	179,198,714	161,866,955
Contingent securities/Share based compensation (in shares)	588,647	1,587,148	789,778	1,487,015
Diluted weighted average shares outstanding (in shares)	178,776,684	173,193,870	179,988,492	163,353,970
Earnings per common share from continuing operations Abstract
Income (loss) from continuing operations attributable to common shareholders, Basic (USD per share)	$ 0.10	$ 0.04	$ 0.15	$ 0.01
Income (loss) from continuing operations attributable to common shareholders, Dilued (USD per share)	0.10	0.04	0.15	0.01
Discontinued operations attributable to common shareholders, Basic (USD per share)	0.00	0.00	0.00	0.01
Discontinued operations attributable to common shareholders, Diluted (USD per share)	0.00	0.00	0.00	0.01
Net income (loss) attributable to common shareholders, Basic (USD per share)	0.10	0.04	0.15	0.02
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ 0.10	$ 0.04	$ 0.15	$ 0.02