PARTNERS' EQUITY OF THE PARENT COMPANY- 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, 2022	Mar. 31, 2021
Numerator
Net income	$ 6,101	$ 6,964
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(148)	(146)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	$ (148)	$ (146)
Denominator
Weighted average units outstanding, basic (in shares)	171,294,949	170,624,741
Contingent securities/Share based compensation (in shares)	1,594,045	1,011,379
Weighted average units outstanding, diluted (in shares)	172,888,994	171,636,120
Earnings per Common Partnership Unit:
Net income attributable to common shareholders, Basic (in dollars per share)	$ 0.03	$ 0.04
Net income attributable to common shareholders, Diluted (in dollars per share)	$ 0.03	$ 0.04
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Net income	$ 6,101	$ 6,964
Net (income) loss attributable to noncontrolling interests	2	1
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(148)	(146)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	(148)	(146)
Net income (loss) attributable to common unitholders, Basic	5,955	6,819
Net income (loss) attributable to common unitholders, Diluted	$ 5,955	$ 6,819
Denominator
Weighted average units outstanding, basic (in shares)	171,927,588	171,606,375
Contingent securities/Share based compensation (in shares)	1,594,045	1,011,379
Weighted average units outstanding, diluted (in shares)	173,521,633	172,617,754
Earnings per Common Partnership Unit:
Net income attributable to common shareholders, Basic (in dollars per share)	$ 0.03	$ 0.04
Net income attributable to common shareholders, Diluted (in dollars per share)	$ 0.03	$ 0.04