BENEFICIARIES' EQUITY OF THE PARENT COMPANY - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Numerator
Net loss	$ (16,414)	$ (5,276)
Net loss attributable to noncontrolling interests, Basic	46	17
Net loss attributable to noncontrolling interests, Diluted	46	17
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(336)	(70)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	(336)	(70)
Net loss attributable to Common Shareholders of Brandywine Realty Trust	(16,704)	(5,329)
Net income (loss) attributable to common shareholders, diluted	$ (16,704)	$ (5,329)
Denominator
Basic weighted average shares outstanding (in shares)	172,207,037	171,673,167
Weighted average shares outstanding, diluted (in shares)	172,207,037	171,673,167
Loss per Common Share:
Net loss attributable to common shareholders, Basic (in dollars per share)	$ (0.10)	$ (0.03)
Net loss attributable to common shareholders, Diluted (in dollars per share)	$ (0.10)	$ (0.03)