Beneficiaries Equity of the Parent Company - Number of Shares and Net Income Used to Calculate Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Numerator
Income from continuing operations, Basic	$ 21,271	$ 46,310
Net income from continuing operations attributable to non-controlling interests, Basic	(169)	(389)
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(99)	(105)
Distribution to preferred shareholders	(1,725)	(1,725)
Net income attributable to Common Shareholders of Brandywine Realty Trust	19,278	44,091
Net income from continuing operations attributable to non-controlling interests, Diluted	(169)	(389)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	(99)	(105)
Net income attributable to common shareholders, Diluted	$ 19,278	$ 44,091
Denominator
Basic weighted average shares outstanding (in shares)	175,176,964	174,788,945
Contingent securities/Share based compensation (in shares)	1,024,908	682,468
Diluted weighted average shares outstanding (in shares)	176,201,872	175,471,413
Earnings per Common Share:
Net income attributable to common shareholders, Basic (USD per share)	$ 0.11	$ 0.25
Net income attributable to common shareholders, Diluted (USD per share)	$ 0.11	$ 0.25