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				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Numerator
Net income (loss)	$ (12,737)	$ (5,276)	$ 4,651	$ 6,101	$ (18,013)	$ 10,752
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(204)		(98)		(274)	(246)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	$ (204)		$ (98)		$ (274)	$ (246)
Denominator
Weighted average units outstanding, basic (in shares)	171,962,162		171,527,031		171,818,463	171,411,631
Contingent securities/Share based compensation (in shares)	0		733,398		0	1,163,777
Weighted average shares outstanding, diluted (in shares)	171,962,162		172,260,429		171,818,463	172,575,408
Earnings (loss) per Common Partnership Unit:
Net income (loss) attributable to common shareholders, Basic (in dollars per share)	$ (0.08)		$ 0.03		$ (0.11)	$ 0.06
Net income (loss) attributable to common shareholders, Diluted (in dollars per share)	$ (0.08)		$ 0.03		$ (0.11)	$ 0.06
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Net income (loss)	$ (12,737)	$ (5,276)	$ 4,651	$ 6,101	$ (18,013)	$ 10,752
Net loss attributable to noncontrolling interests	0		2		1	4
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(204)		(98)		(274)	(246)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	(204)		(98)		(274)	(246)
Net income (loss) attributable to common unitholders, Basic	(12,941)		4,555		(18,286)	10,510
Net income (loss) attributable to common unitholders, Diluted	$ (12,941)		$ 4,555		$ (18,286)	$ 10,510
Denominator
Weighted average units outstanding, basic (in shares)	172,478,629		172,043,498		172,334,930	171,985,863
Contingent securities/Share based compensation (in shares)	0		733,398		0	1,163,777
Weighted average shares outstanding, diluted (in shares)	172,478,629		172,776,896		172,334,930	173,149,640
Earnings (loss) per Common Partnership Unit:
Net income (loss) attributable to common shareholders, Basic (in dollars per share)	$ (0.08)		$ 0.03		$ (0.11)	$ 0.06
Net income (loss) attributable to common shareholders, Diluted (in dollars per share)	$ (0.08)		$ 0.03		$ (0.11)	$ 0.06