Investments in Unconsolidated Entities and International Investments - Combined Balance Sheets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Our Share of:
Investment in unconsolidated entities, at equity	$ 2,197,309	$ 2,220,414
Unconsolidated properties | Maximum
Our Share of:
Estimated life of investment property	40 years
Equity Method Investees excluding Klepierre, Aeropostale, ABG and HBS | Unconsolidated properties
Assets:
Investment properties, at cost	$ 18,887,972	18,807,449
Less - accumulated depreciation	6,971,412	6,834,633
Investment properties at cost, net	11,916,560	11,972,816
Cash and cash equivalents	1,012,497	1,076,398
Tenant receivables and accrued revenue, net	407,040	445,148
Deferred costs and other assets	617,399	390,818
Total assets	13,953,496	13,885,180
Liabilities and Partners' Deficit:
Mortgages	15,202,622	15,235,415
Accounts payable, accrued expenses, intangibles, and deferred revenue	876,348	976,311
Other liabilities	560,101	344,205
Total liabilities	16,639,071	16,555,931
Preferred units	67,450	67,450
Partners' deficit	(2,753,025)	(2,738,201)
Total liabilities and partners' deficit	13,953,496	13,885,180
Our Share of:
Partners' deficit	(1,184,895)	(1,168,216)
Add: Excess Investment	1,581,225	1,594,198
Investment in unconsolidated entities, at equity	$ 396,330	$ 425,982