Investments in Unconsolidated Entities - Combined Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
OPERATING EXPENSES:
Income from Unconsolidated Entities	$ 90,026	$ 69,085
Equity Method Investees excluding Klepierre, Aeropostale and HBS | Unconsolidated properties
REVENUE:
Minimum rent	475,956	451,055
Overage rent	59,661	51,369
Tenant reimbursements	223,490	215,780
Other income	81,108	64,327
Total revenue	840,215	782,531
OPERATING EXPENSES:
Property operating	146,293	132,985
Depreciation and amortization	159,836	153,455
Real estate taxes	68,267	66,583
Repairs and maintenance	23,196	20,230
Advertising and promotion	24,224	22,198
Provision for credit losses	6,501	3,777
Other	49,732	43,355
Total operating expenses	478,049	442,583
Operating Income	362,166	339,948
Interest expense	(150,932)	(142,204)
Net Income	211,234	197,744
Third-Party Investors’ Share of Net Income	106,183	99,686
Our Share of Net Income	105,051	98,058
Amortization of Excess Investment	(21,527)	(22,457)
Income from Unconsolidated Entities	$ 83,524	$ 75,601