Deferred Costs, Acquired Lease Intangibles and Goodwill - Amortizing Acquired Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Acquired below-market ground leases
Acquired below-market ground leases, gross	$ 396,916	$ 396,916
Less: accumulated amortization	(30,645)	(28,687)
Acquired below-market ground leases, net	366,271	368,229
Acquired below-market leases
Acquired below-market leases, gross	(124,615)	(132,026)
Less: accumulated amortization	62,197	65,979
Acquired below-market leases, net	$ (62,418)	$ (66,047)

Amount of accumulated amortization of leases acquired as part of a real property acquisition at below market lease rate with a finite life.

No definition available.

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Amount before amortization of leases acquired as part of a real property acquisition at below market lease rate with a finite life.

No definition available.

Name:	us-gaap_BelowMarketLeaseGross
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Data Type:	xbrli:monetaryItemType
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Amount after amortization of leases acquired as part of a real property acquisition at below market lease rate with a finite life.

No definition available.

Name:	us-gaap_BelowMarketLeaseNet
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No definition available.

Name:	us-gaap_BelowMarketLeaseNetAbstract
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Accumulated amortization on long-term land leases capitalized as part of real property.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Gross long-term land leases capitalized as part of real property.

No definition available.

Net long-term land leases which are capitalized as part of real property.

No definition available.

No definition available.

Name:	us-gaap_GroundLeasesNetAbstract
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