Investments in Unconsolidated Entities and International Investments - Combined Balance Sheets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Our Share of:
Equity investment	$ 1,731,649	$ 1,769,488
Unconsolidated properties
Our Share of:
Estimated life of investment property	40 years
Equity Method Investees excluding Klepierre, Aeropostale, ABG, HBS and RGG | Unconsolidated properties
Assets:
Investment properties, at cost	$ 19,525,665	18,807,449
Less - accumulated depreciation	7,407,627	6,834,633
Investment properties at cost, net	12,118,038	11,972,816
Cash and cash equivalents	1,015,864	1,076,398
Tenant receivables and accrued revenue, net	510,157	445,148
Right-of-use assets, net	185,302
Deferred costs and other assets	384,663	390,818
Total assets	14,214,024	13,885,180
Liabilities and Partners' Deficit:
Mortgages	15,391,781	15,235,415
Accounts payable, accrued expenses, intangibles, and deferred revenue	977,112	976,311
Lease liabilities	186,594
Other liabilities	338,412	344,205
Total liabilities	16,893,899	16,555,931
Preferred units	67,450	67,450
Partners' deficit	(2,747,325)	(2,738,201)
Total liabilities and partners' deficit	14,214,024	13,885,180
Our Share of:
Partners' deficit	(1,196,926)	(1,168,216)
Add: Excess Investment	1,525,903	1,594,198
Equity investment	$ 328,977	$ 425,982