Segment Information - Reconciliation of Consolidated Net Income to Consolidated NOI (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting [Abstract]
Net income	$ 974	$ (175)	$ 6,964	$ 276,133	$ 4,020	$ 8,087	$ 7,763	$ 288,240
Plus:
Interest expense	15,190			16,310			46,973	56,510
Interest expense - amortization of deferred financing costs	709			715			2,127	2,195
Depreciation and amortization	48,175			43,533			131,303	145,314
General and administrative expenses	7,076			7,069			22,016	23,973
Equity in loss of unconsolidated real estate ventures	6,634			5,788			20,798	9,882
Less:
Interest and investment income	4,494			467			7,845	1,487
Income tax (provision) benefit	(12)			(2)			(46)	224
Net gain on disposition of real estate	0			271,901			142	274,487
Net gain on sale of undepreciated real estate	910			0			2,903	201
Net gain on real estate venture transactions	0			75			0	75
Consolidated net operating income	$ 73,366			$ 77,107			$ 220,136	$ 249,640