Deferred Costs, Acquired Lease Intangibles and Goodwill - Amortizing Acquired Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Acquired below-market ground leases, net
Acquired below-market ground leases	$ 396,916	$ 396,916
Less: accumulated amortization	(42,392)	(36,518)
Acquired below-market ground leases, net	354,524	360,398
Acquired below-market leases, net
Acquired below-market leases	(113,625)	(118,462)
Less: accumulated amortization	70,970	66,012
Acquired below-market leases, net	$ (42,655)	$ (52,450)

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.

Name:	us-gaap_BelowMarketLeaseAccumulatedAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

No definition available.

Name:	us-gaap_BelowMarketLeaseNetAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Accumulated amortization on long-term land leases capitalized as part of real property.

No definition available.

Name:	us-gaap_GroundLeasesAccumulatedAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration