PARTNERS' EQUITY OF THE PARENT COMPANY - Narrative (Details) $ / shares in Units, $ in Millions			12 Months Ended
	Jan. 18, 2024 $ / shares	Dec. 05, 2023 USD ($) $ / shares	Dec. 31, 2023 class_of_units $ / shares shares	Dec. 31, 2022 $ / shares shares	Dec. 31, 2021 $ / shares shares
Earnings Per Common Partnership Unit [Line Items]
Number of classes of partnership units | class_of_units			2
Amount of dividend declared | $		$ 26.0
Repurchased and retired (in shares) | shares			0	0
Dividends paid in cash (in dollars per share)			$ 0.72	$ 0.76	$ 0.76
Distributions declared (in dollars per share)		$ 0.15	0.68	0.76	0.76
Subsequent Event
Earnings Per Common Partnership Unit [Line Items]
Dividends paid in cash (in dollars per share)	$ 0.15
Class A Units
Earnings Per Common Partnership Unit [Line Items]
Redeemable limited partnership unit price (in dollars per share)			$ 5.40	$ 6.15	$ 13.42
Limited partners' capital account, units outstanding (in units) | shares			515,595	516,467	823,983
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Preferred units, outstanding (in units) | shares			0	0
Amount of dividend declared | $		$ 26.0
Repurchase program, number of mirror unit of operating partnership retired for each common share repurchased | shares			1
Distributions declared (in dollars per share)		$ 0.15
BRANDYWINE OPERATING PARTNERSHIP, L.P. | Subsequent Event
Earnings Per Common Partnership Unit [Line Items]
Dividends paid in cash (in dollars per share)	$ 0.15