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
	Mar. 31, 2023	Mar. 31, 2022
Numerator
Net income (loss)	$ (5,276)	$ 6,101
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(70)	(148)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	$ (70)	$ (148)
Denominator
Weighted average units outstanding, basic (in shares)	171,673,167	171,294,949
Contingent securities/Share based compensation (in shares)	0	1,594,045
Weighted average units outstanding, diluted (in shares)	171,673,167	172,888,994
Earnings (loss) per Common Partnership Unit:
Net income (loss) attributable to common shareholders, Basic (in dollars per share)	$ (0.03)	$ 0.03
Net income (loss) attributable to common shareholders, Diluted (in dollars per share)	$ (0.03)	$ 0.03
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Net income (loss)	$ (5,276)	$ 6,101
Net loss attributable to noncontrolling interests	1	2
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(70)	(148)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	(70)	(148)
Net income (loss) attributable to common unitholders, Basic	(5,345)	5,955
Net income (loss) attributable to common unitholders, Diluted	$ (5,345)	$ 5,955
Denominator
Weighted average units outstanding, basic (in shares)	172,189,634	171,927,588
Contingent securities/Share based compensation (in shares)	0	1,594,045
Weighted average units outstanding, diluted (in shares)	172,189,634	173,521,633
Earnings (loss) per Common Partnership Unit:
Net income (loss) attributable to common shareholders, Basic (in dollars per share)	$ (0.03)	$ 0.03
Net income (loss) attributable to common shareholders, Diluted (in dollars per share)	$ (0.03)	$ 0.03