Summary of Significant Accounting Policies - Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2018	Jan. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing arrangement obligation	$ 273,900		$ 378,485
Accumulated deficit	(1,944,012)		(1,614,357)
Cumulative effect of adoption		$ (2,203)		$ (424,859)	$ 6,484
Right-of-use assets, net	148,087
Total lease liabilities	100,405
Deferred charges and other assets, net	(277,866)		(390,403)
Accounts payable and accrued expenses	51,027		59,392
Other accrued liabilities	265,595		$ 303,051
Total lease liabilities	$ 13,796
Freehold Raceway Mall and Chandler Fashion Center | Joint venture
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]
Cumulative effect of adoption		(2,203)
Right-of-use assets, net		109,299
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)
Total lease liabilities		$ 15,268
ASU 2014-09 | Joint venture | Financing arrangement | Difference between revenue guidance in effect before and after topic 606 | Freehold Raceway Mall and Chandler Fashion Center
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing arrangement obligation				393,709
Accumulated deficit				$ 424,859