Real Estate Investment in Real Estate - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Land	$ 5,899,862	$ 5,864,046
Depreciable property [Abstract]
Buildings and improvements	16,913,430	16,346,829
Furniture, fixtures and equipment	1,346,300	1,207,098
Finite-Lived Intangible Asset, Acquired-in-Place Leases	470,849	483,160
Projects under development [Abstract]
Construction-in-progress	637,168	1,122,376
Land held for development [Abstract]
Land held for development	118,816	158,843
Construction-in-progress	637,168	1,122,376
Investment in real estate	25,386,425	25,182,352
Accumulated depreciation	(5,360,389)	(4,905,406)
Investment in real estate, net	20,026,036	20,276,946
Amortization of above/below market leases	3,426	3,382	$ 3,222
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	3,781
Finite-Lived Intangible Assets, Amortization Expense, Year Two	4,250
Finite-Lived Intangible Assets, Amortization Expense, Year Three	4,250
Finite-Lived Intangible Assets, Amortization Expense, Year Four	4,250
Finite-Lived Intangible Assets, Amortization Expense, Year Five	4,254
Assets [Member]
Land held for development [Abstract]
Below Market Lease, Gross	178,251	178,251
Finite-Lived Intangible Asset, Off-market Lease, Favorable, Gross	1,260	1,260
Lease intangible assets	179,511	179,511
Finite-Lived Intangible Assets, Accumulated Amortization	(17,972)	(13,451)
Finite-Lived Intangible Assets, Net	161,539	166,060
Liability [Member]
Land held for development [Abstract]
Below Market Lease, Gross	5,270	5,270
Ground lease intangibles – above market	2,400	2,400
Lease Intangible Liabilities	7,670	7,670
Finite Lived Intangible Liabilities Accumulated Amortization	(4,509)	(3,414)
Lease Intangible Liabilities, net	3,161	4,256
Ground Lease [Member]
Land held for development [Abstract]
Amortization of above/below market leases	4,300	4,300	4,300
Finite-lived Intangible Assets; Amortization Exp, Next Twelve Months	4,321
Finite-lived Intangible Assets; Amortization Exp, Year 2	4,321
Finite-lived Intangible Assets; Amortization Exp, Year 3	4,321
Finite-lived Intangible Assets; Amortization Exp, Year 4	4,321
Finite-lived Intangible Assets; Amortization Exp, Year 5	4,321
Retail Site [Member]
Land held for development [Abstract]
Amortization of above/below market leases	900	900	$ 1,100
Finite-lived Intangible Assets; Amortization Exp, Next Twelve Months	(540)
Finite-lived Intangible Assets; Amortization Exp, Year 2	(71)
Finite-lived Intangible Assets; Amortization Exp, Year 3	(71)
Finite-lived Intangible Assets; Amortization Exp, Year 4	(71)
Finite-lived Intangible Assets; Amortization Exp, Year 5	(67)
Projects under development [Member]
Projects under development [Abstract]
Land Under Development	115,876	284,995
Construction-in-progress	521,292	837,381
Land held for development [Abstract]
Construction-in-progress	521,292	837,381
Land held for development [Member]
Projects under development [Abstract]
Construction-in-progress	34,376	38,836
Land held for development [Abstract]
Land held for development	84,440	120,007
Construction-in-progress	$ 34,376	$ 38,836