Real Estate (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Land	$ 5,835,195		$ 5,835,195		$ 5,864,046
Depreciable property:
Buildings and improvements	16,735,299		16,735,299		16,346,829
Furniture, fixtures and equipment	1,269,413		1,269,413		1,207,098
In-Place lease intangibles	469,679		469,679		483,160
Land Available for Development	138,221		138,221		158,843
Construction-in-progress	799,947		799,947		1,122,376
Investment in real estate	25,247,754		25,247,754		25,182,352
Accumulated depreciation	(5,119,342)		(5,119,342)		(4,905,406)
Investment in real estate, net	20,128,412		20,128,412		20,276,946
Lease intangible assets	179,511		179,511		179,511
Accumulated amortization	(15,712)		(15,712)		(13,451)
Lease intangible assets, net	163,799		163,799		166,060
Lease intangible liabilities	7,670		7,670		7,670
Accumulated amortization	(3,967)		(3,967)		(3,414)
Lease intangible liabilities, net	3,703		3,703		4,256
Amortization of above/below market leases			1,708	$ 1,691
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	1,717		1,717
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	3,781		3,781
Finite-Lived Intangible Assets, Amortization Expense, Year Two	4,250		4,250
Finite-Lived Intangible Assets, Amortization Expense, Year Three	4,250		4,250
Finite-Lived Intangible Assets, Amortization Expense, Year Four	4,250		4,250
Finite-Lived Intangible Assets, Amortization Expense, Year Five	4,254		4,254
Assets [Member]
Depreciable property:
Lease intangibles – below market	178,251		178,251		178,251
Retail lease intangibles – above market	1,260		1,260		1,260
Ground Lease [Member]
Depreciable property:
Amortization of above/below market leases	1,100	$ 1,100	2,200	2,200
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	2,161		2,161
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	4,321		4,321
Finite-Lived Intangible Assets, Amortization Expense, Year Two	4,321		4,321
Finite-Lived Intangible Assets, Amortization Expense, Year Three	4,321		4,321
Finite-Lived Intangible Assets, Amortization Expense, Year Four	4,321		4,321
Finite-Lived Intangible Assets, Amortization Expense, Year Five	4,321		4,321
Retail Site [Member]
Depreciable property:
Amortization of above/below market leases	300	$ 300	500	$ 500
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	(444)		(444)
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	(540)		(540)
Finite-Lived Intangible Assets, Amortization Expense, Year Two	(71)		(71)
Finite-Lived Intangible Assets, Amortization Expense, Year Three	(71)		(71)
Finite-Lived Intangible Assets, Amortization Expense, Year Four	(71)		(71)
Finite-Lived Intangible Assets, Amortization Expense, Year Five	(67)		(67)
Liability [Member]
Depreciable property:
Lease intangibles – below market	5,270		5,270		5,270
Ground lease intangibles – above market	2,400		2,400		2,400
Projects under development [Member]
Depreciable property:
Land	188,563		188,563		284,995
Construction-in-progress	611,384		611,384		837,381
Land held for development [Member]
Depreciable property:
Land Available for Development	98,549		98,549		120,007
Construction-in-progress	$ 39,672		$ 39,672		$ 38,836