Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Preferred Stock, Value, Issued	$ 40	$ 40
Brandywine Realty Trust's equity:
Preferred shares, shares authorized	20,000,000	20,000,000
Preferred shares, dividend rate (as a percent)	6.90%	6.90%
Preferred shares, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred shares, shares issued	4,000,000	4,000,000
Preferred shares, shares outstanding	4,000,000	4,000,000
Common shares in grantor trust	$ 0.01	$ 0.01
Common shares of Brandywine Realty Trust's beneficial interest, shares authorized	400,000,000	200,000,000
Common shares of Brandywine Realty Trust's beneficial interest, shares issued	179,293,160	156,731,993
Common shares of Brandywine Realty Trust's beneficial interest, shares outstanding	179,293,160	156,731,993
Common shares in grantor trust	384,386	312,280
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Preferred Stock, Value, Issued	$ 96,850	$ 96,850
Brandywine Realty Trust's equity:
Preferred shares, dividend rate (as a percent)	6.90%	6.90%
Preferred shares, shares issued	4,000,000	4,000,000
Preferred shares, shares outstanding	4,000,000	4,000,000
Redeemable Limited Partnership, units issued	1,535,102	1,763,739
Redeemable Limited Partnership, units outstanding	1,535,102	1,763,739
General Partners' Capital account, units issued	179,293,160	156,731,993
General Partners' Capital account, units outstanding	179,293,160	156,731,993