Investments in Unconsolidated Joint Ventures - Schedules of Combined Financial Statements for the Unconsolidated Joint Ventures (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Commercial real estate property, net	$ 6,724,007				$ 6,414,798				$ 6,724,007	$ 6,414,798
Cash and restricted cash	166,070				129,475				166,070	129,475	$ 127,888
Tenant and other receivables and deferred rents receivable	43,968				41,589				43,968	41,589
Debt and preferred equity investments	1,580,306				2,099,393				1,580,306	2,099,393
Other assets	332,801				295,679				332,801	295,679
Liabilities and equity
Mortgages and other loans payable, net	2,183,253				1,961,240				2,183,253	1,961,240
Lease liabilities	381,671				3,603				381,671	3,603
Other liabilities	177,080				116,566				177,080	116,566
Company's investments in unconsolidated joint ventures	2,912,842				3,019,020				2,912,842	3,019,020
Investments difference between carrying amount and underlying equity	133,100								133,100
Combined statements of income for the unconsolidated joint ventures
Real estate taxes									190,764	186,351	244,323
Amortization of deferred financing costs									11,653	12,408	16,498
Transaction related costs									729	1,099	(1,834)
Depreciation and amortization									272,358	279,507	403,320
Total expenses	252,712	$ 263,341	$ 258,383	$ 260,328	267,678	$ 265,553	$ 258,303	$ 258,282	1,034,764	1,049,816	1,346,445
Company's equity in net (loss) income from unconsolidated joint ventures	(11,874)	$ (9,864)	$ (7,546)	$ (5,234)	(2,398)	$ 971	$ 4,702	$ 4,036	(34,518)	7,311	21,892
Joint venture
Assets
Commercial real estate property, net	14,349,628				14,347,673				14,349,628	14,347,673
Cash and restricted cash	336,189				381,301				336,189	381,301
Tenant and other receivables and deferred rents receivable	371,065				273,141				371,065	273,141
Debt and preferred equity investments	0				44,357				0	44,357
Other assets	2,039,429				2,187,166				2,039,429	2,187,166
Total assets	17,096,311				17,233,638				17,096,311	17,233,638
Liabilities and equity
Mortgages and other loans payable, net	8,951,869				8,950,622				8,951,869	8,950,622
Deferred revenue	1,501,616				1,660,838				1,501,616	1,660,838
Lease liabilities	897,380				637,168				897,380	637,168
Other liabilities	308,304				309,145				308,304	309,145
Equity	5,437,142				5,675,865				5,437,142	5,675,865
Total liabilities and equity	17,096,311				$ 17,233,638				17,096,311	17,233,638
Company's investments in unconsolidated joint ventures	$ 2,912,842								2,912,842
Combined statements of income for the unconsolidated joint ventures
Total revenues									1,163,534	1,244,804	904,230
Operating expenses									202,881	219,440	157,610
Real estate taxes									212,355	226,961	142,774
Operating lease, rent									24,816	18,697	16,794
Interest expense, net of interest income									372,408	363,055	250,063
Amortization of deferred financing costs									19,336	21,634	23,026
Transaction related costs									0	0	146
Depreciation and amortization									407,697	421,458	279,419
Total expenses									1,239,493	1,271,245	869,832
Loss on early extinguishment of debt									(1,031)	0	(7,899)
Net (loss) income before gain on sale									(76,990)	(26,441)	26,499
Company's equity in net (loss) income from unconsolidated joint ventures									(34,518)	7,311	21,892
Management Service, Base | Joint venture
Investment in Unconsolidated Joint Ventures
Management fees, base revenue									$ 13,000	$ 14,200	$ 22,600