BENEFICIARIES' EQUITY OF THE PARENT COMPANY - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2025	Mar. 31, 2025	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2025	Jun. 30, 2024
Numerator
Net income (loss)	$ (88,936)	$ (27,056)	$ 30,267	$ (16,414)	$ (115,992)	$ 13,853
Basic
Net (income) loss attributable to noncontrolling interests	267		(94)		348	(48)
Nonforfeitable dividends allocated to unvested restricted shareholders	(322)		(277)		(751)	(613)
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	(88,991)		29,896		(116,395)	13,192
Diluted
Net (income) loss attributable to noncontrolling interests	267		(94)		348	(48)
Nonforfeitable dividends allocated to unvested restricted shareholders	(322)		(277)		(751)	(613)
Net income (loss) attributable to common shareholders	$ (88,991)		$ 29,896		$ (116,395)	$ 13,192
Denominator
Basic weighted average shares outstanding (in shares)	173,532,583		172,563,136		173,225,737	172,385,087
Contingent securities/Share based compensation (in shares)	0		2,132,515		0	1,957,064
Weighted average shares outstanding, diluted (in shares)	173,532,583		174,695,651		173,225,737	174,342,151
Earnings (loss) per Common Share:
Net income (loss) attributable to common shareholders, basic (in dollars per share)	$ (0.51)		$ 0.17		$ (0.67)	$ 0.08
Net income (loss) attributable to common shareholders, diluted (in dollars per share)	$ (0.51)		$ 0.17		$ (0.67)	$ 0.08