Real Estate Activities - Impairment of Assets (Details) - USD ($) $ in Thousands			12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2022	Dec. 31, 2021
Impairment Of Assets [Line Items]
Impairment of real estate assets			$ 44,101	$ 9,938
Plymouth Meeting Mall
Impairment Of Assets [Line Items]
Impairment of real estate assets			39,256
Cumberland Mall
Impairment Of Assets [Line Items]
Impairment of real estate assets			$ 4,845
Exton Square Mall
Impairment Of Assets [Line Items]
Impairment of real estate assets				8,374
Valley View Center
Impairment Of Assets [Line Items]
Impairment of real estate assets		$ 1,300		1,302
Monroe Marketplace
Impairment Of Assets [Line Items]
Impairment of real estate assets	$ 300			$ 262