ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		$ 1,633,334	$ 1,701,219	$ 1,804,648
Change in fair market value during year		(4,579)	5,371	4,817
Allocation of unrealized (gains)/losses on derivative financial instruments to noncontrolling interests		14	(18)	(28)
Amortization of interest rate contracts reclassified from comprehensive income to interest expense	[1]	0	564	752
Ending balance		1,324,157	1,633,334	1,701,219
Operating Partnership
Change in fair market value during year		(4,579)	5,371	4,817
Amortization of interest rate contracts reclassified from comprehensive income to interest expense	[1]	0	564	752
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change in fair market value during year		(4,579)	5,371	4,817
Amortization of interest rate contracts reclassified from comprehensive income to interest expense	[1]	0	564	752
Operating Partnership
Beginning balance		1,630,139	1,690,079	1,793,082
Change in fair market value during year		(4,579)	5,371	4,817
Amortization of interest rate contracts reclassified from comprehensive income to interest expense	[1]	0	564	752
Ending balance		1,321,372	1,630,139	1,690,079
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		3,897	(2,020)	(7,561)
Ending balance		(668)	3,897	(2,020)
Accumulated Other Comprehensive Income (Loss) | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Operating Partnership
Beginning balance		3,569	(2,366)	(7,935)
Ending balance		$ (1,010)	$ 3,569	$ (2,366)

[1] Amounts reclassified from comprehensive income to interest expense within the Consolidated Statements of Operations.