(Transaction Related Costs and Other) Lease Liability Extinguishment Gain - (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Transaction Related Costs, Impairment Losses and Lease Termination Gain [Line Items]
Transaction related costs, impairment losses and other	$ (106)	$ 69,221	$ (949)	$ 69,150
608 Fifth Avenue
Transaction Related Costs, Impairment Losses and Lease Termination Gain [Line Items]
608 Fifth Avenue lease liability extinguishment gain	0	70,260	0	70,260
Transaction related costs and other	$ (106)	$ (1,039)	$ (949)	$ (1,110)