Real Estate and Lease Intangibles - Summary of Carrying Amounts of Investment in Real Estate (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Land	$ 5,866,457	$ 5,996,024
Depreciable property:
Buildings and improvements	18,174,939	17,743,042
Furniture, fixtures and equipment	1,684,794	1,548,961
In-Place lease intangibles	477,014	476,359
Projects under development:
Construction-in-progress	134,961	163,547
Land held for development:
Land	87,335	98,963
Construction-in-progress	134,961	163,547
Investment in real estate	26,425,500	26,026,896
Accumulated depreciation	(6,494,770)	(6,040,378)
Investment in real estate, net	19,930,730	19,986,518
Projects under development [Member]
Projects under development:
Land	34,689	43,226
Construction-in-progress	100,272	120,321
Land held for development:
Construction-in-progress	100,272	120,321
Land held for development [Member]
Projects under development:
Construction-in-progress	26,297	36,425
Land held for development:
Land	61,038	62,538
Construction-in-progress	$ 26,297	$ 36,425

Carrying amount of land for a real estate project that has not yet been completed.

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Land held for development [Abstract]

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Projects under development [Abstract]

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The current amount of expenditures for a real estate project that has not yet been completed.

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This element represents the amount of value allocated by a lessor (acquirer) to lease agreements which exist at acquisition of a leased property. Such amount may include the value assigned to existing tenant relationships and excludes the market adjustment component of the value assigned for above or below-market leases acquired.

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Amount before accumulated depreciation of fixtures and equipment. Includes, but is not limited to, machinery, equipment, and engines.

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No definition available.

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Aggregate of the carrying amounts as of the balance sheet date of investments in building and building improvements.

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Amount before accumulated depletion of real estate held for productive use, excluding land held for sale.

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Carrying amount of land available for development.

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The cumulative amount of depreciation for real estate property held for investment purposes.

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Amount of real estate investment property which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

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Amount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

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