Investments in Unconsolidated Joint Ventures - Schedules of Combined Financial Statements for the Unconsolidated Joint Ventures (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Assets
Commercial real estate property, net	$ 6,941,094		$ 6,941,094		$ 6,414,798
Cash and cash equivalents	121,751	$ 160,248	121,751	$ 160,248	129,475
Tenant and other receivables, related party receivables, and deferred rents receivable	44,950		44,950		41,589
Other assets	271,467		271,467		295,679
Liabilities and equity
Mortgages and other loans payable, net	2,417,161		2,417,161		1,961,240
Deferred revenue/gain	126,321		126,321		94,453
Lease liabilities	384,661		384,661		3,603
Other liabilities	140,899		140,899		116,566
Company's investments in unconsolidated joint ventures	2,923,595		2,923,595		3,019,020
Combined statements of income for the unconsolidated joint ventures
Operating expenses	59,847	56,852	175,862	172,871
Operating lease rent	8,295	9,507	24,891	26,661
Real estate taxes	49,626	48,805	143,008	139,788
Interest expense, net of interest income	48,112	55,168	145,797	156,695
Amortization of deferred financing costs	3,112	2,630	8,566	9,713
Transaction related costs	44	163	360	673
Depreciation and amortization	70,464	70,747	208,268	208,049
Total expenses	263,341	265,553	782,052	782,138
Loss on early extinguishment of debt	0	(2,194)	0	(2,194)
Company's equity in net (loss) income from unconsolidated joint ventures	(9,864)	971	(22,644)	9,709
Joint venture
Assets
Commercial real estate property, net	14,280,158		14,280,158		14,347,673
Cash and cash equivalents	299,699		299,699		381,301
Tenant and other receivables, related party receivables, and deferred rents receivable	360,394		360,394		273,141
Debt and preferred equity investments, net	0		0		44,357
Other assets	2,084,421		2,084,421		2,187,166
Total assets	17,024,672		17,024,672		17,233,638
Liabilities and equity
Mortgages and other loans payable, net	8,799,015		8,799,015		8,950,622
Deferred revenue/gain	1,535,067		1,535,067		1,660,838
Lease liabilities	898,996		898,996		637,168
Other liabilities	300,576		300,576		309,145
Equity	5,491,018		5,491,018		5,675,865
Total liabilities and equity	17,024,672		17,024,672		17,233,638
Company's investments in unconsolidated joint ventures	2,923,595		2,923,595		$ 3,019,020
Combined statements of income for the unconsolidated joint ventures
Total revenues	286,010	304,869	883,977	940,005
Operating expenses	50,759	56,304	153,397	166,433
Operating lease rent	6,713	4,397	18,848	13,247
Real estate taxes	53,321	56,747	159,544	169,612
Interest expense, net of interest income	92,601	88,328	282,917	269,717
Amortization of deferred financing costs	4,436	4,446	14,434	16,912
Depreciation and amortization	100,736	101,538	308,748	318,113
Total expenses	308,566	311,760	937,888	954,034
Loss on early extinguishment of debt	(1,031)	0	(1,031)	0
Net loss before gain on sale	(23,587)	(6,891)	(54,942)	(14,029)
Company's equity in net (loss) income from unconsolidated joint ventures	(9,864)	971	(22,644)	9,709
Management Service, Base | Joint venture
Investment in Unconsolidated Joint Ventures
Escalation and reimbursement	$ 2,400	$ 2,400	$ 8,800	$ 9,300