Summary of Significant Accounting Policies - Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing arrangement obligation	$ 134,379	$ 273,900
Accumulated deficit	(2,339,619)	(1,944,012)
Cumulative effect of adoption	2,445,260	2,830,970		$ 3,188,432		$ 3,967,999
Total lease liabilities	73,839
Deferred charges and other assets, net	306,959	277,866
Accounts payable and accrued expenses	68,825	51,027
Other accrued liabilities	298,594	265,595
Total lease liabilities	16,377		$ 15,268
Accumulated Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption	$ (2,339,619)	$ (1,944,012)		(1,614,357)		(830,279)
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption				(2,203)		(424,859)
Cumulative Effect, Period of Adoption, Adjustment | Accumulated Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption				$ (2,203)		$ (424,859)
Joint venture | Financing arrangement | Freehold Raceway Mall and Chandler Fashion Center | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing arrangement obligation					$ 393,709
Accumulated deficit					424,859
Freehold Raceway Mall and Chandler Fashion Center | Joint venture | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investments in unconsolidated joint ventures					$ 31,150
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total lease liabilities			109,299
Deferred charges and other assets, net			59,736
Accounts payable and accrued expenses			(5,978)
Other accrued liabilities			$ (4,342)