PARTNERS' EQUITY OF THE PARENT COMPANY - Schedule of Number of Units and Net Income Used to Calculate Basic and Diluted Earnings Per Common Partnership Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator
Net loss	$ (165,720)	$ 30,267	$ (16,414)	$ (21,636)	$ (12,737)	$ (5,276)	$ (151,867)	$ (39,649)
Nonforfeitable dividends allocated to unvested restricted shareholders, basic	(276)			(159)			(889)	(433)
Nonforfeitable dividends allocated to unvested restricted unitholders, Diluted	$ (276)			$ (159)			$ (889)	$ (433)
Denominator
Weighted average units outstanding, basic (in shares)	172,668,731			172,097,661			172,480,325	171,912,552
Weighted average shares outstanding, diluted (in shares)	172,668,731			172,097,661			172,480,325	171,912,552
Loss per Common Partnership Unit:
Net loss attributable to common shareholders, basic (in dollars per share)	$ (0.96)			$ (0.13)			$ (0.88)	$ (0.23)
Net loss attributable to common shareholders, diluted (in dollars per share)	$ (0.96)			$ (0.13)			$ (0.88)	$ (0.23)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Net loss	$ (165,720)	$ 30,267	$ (16,414)	$ (21,636)	$ (12,737)	$ (5,276)	$ (151,867)	$ (39,649)
Net loss attributable to noncontrolling interests	3			20			(3)	21
Nonforfeitable dividends allocated to unvested restricted shareholders, basic	(276)			(159)			(889)	(433)
Nonforfeitable dividends allocated to unvested restricted unitholders, Diluted	(276)			(159)			(889)	(433)
Net income (loss) attributable to common unitholders, basic	(165,993)			(21,775)			(152,759)	(40,061)
Net income (loss) attributable to common unitholders, diluted	$ (165,993)			$ (21,775)			$ (152,759)	$ (40,061)
Denominator
Weighted average units outstanding, basic (in shares)	173,184,325			172,614,128			172,995,920	172,429,019
Weighted average shares outstanding, diluted (in shares)	173,184,325			172,614,128			172,995,920	172,429,019
Loss per Common Partnership Unit:
Net loss attributable to common shareholders, basic (in dollars per share)	$ (0.96)			$ (0.13)			$ (0.88)	$ (0.23)
Net loss attributable to common shareholders, diluted (in dollars per share)	$ (0.96)			$ (0.13)			$ (0.88)	$ (0.23)