Intangible Assets and Liabilities - Intangible Assets and Liabilities Summary (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Intangible Assets Liabilities
Finite lived intangible asset/liability, useful life	20 years
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	$ 740,965	$ 724,067
Less: accumulated amortization	(245,900)	(206,705)
Finite-lived intangible assets, net	495,065	517,362
Indefinite-Lived Intangible Assets
Goodwill	304	304
Total intangible assets, gross	741,269	724,371
Total intangible assets, net	495,369	517,666
Finite-Lived Intangible Liabilities
Finite-lived intangible liabilities, gross	(83,404)	(121,870)
Less: accumulated amortization	22,182	39,071
Finite-lived intangible liabilities, net	(61,222)	(82,799)
Below-market rent
Finite-Lived Intangible Liabilities
Finite-lived intangible liabilities, gross	(82,259)	(120,725)
Less: accumulated amortization	22,121	39,025
Finite-lived intangible liabilities, net	$ (60,138)	(81,700)
Below-market rent | Minimum
Intangible Assets Liabilities
Finite lived intangible asset/liability, useful life	7 years
Below-market rent | Maximum
Intangible Assets Liabilities
Finite lived intangible asset/liability, useful life	53 years
Above-market ground lease
Finite-Lived Intangible Liabilities
Finite-lived intangible liabilities, gross	$ (1,145)	(1,145)
Less: accumulated amortization	61	46
Finite-lived intangible liabilities, net	$ (1,084)	(1,099)
Above-market ground lease | Minimum
Intangible Assets Liabilities
Finite lived intangible asset/liability, useful life	49 years
Above-market ground lease | Maximum
Intangible Assets Liabilities
Finite lived intangible asset/liability, useful life	88 years
In-place lease
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	$ 629,961	620,149
Less: accumulated amortization	(213,641)	(181,598)
Finite-lived intangible assets, net	$ 416,320	438,551
In-place lease | Minimum
Intangible Assets Liabilities
Finite lived intangible asset/liability, useful life	4 years
In-place lease | Maximum
Intangible Assets Liabilities
Finite lived intangible asset/liability, useful life	53 years
Above-market rent
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	$ 98,162	91,895
Less: accumulated amortization	(31,533)	(24,599)
Finite-lived intangible assets, net	$ 66,629	67,296
Above-market rent | Minimum
Intangible Assets Liabilities
Finite lived intangible asset/liability, useful life	5 years
Above-market rent | Maximum
Intangible Assets Liabilities
Finite lived intangible asset/liability, useful life	40 years
Below-market ground leases and other
Finite-Lived Intangible Assets
Finite-lived intangible assets, gross	$ 12,842	12,023
Less: accumulated amortization	(726)	(508)
Finite-lived intangible assets, net	$ 12,116	$ 11,515
Below-market ground leases and other | Minimum
Intangible Assets Liabilities
Finite lived intangible asset/liability, useful life	55 years
Below-market ground leases and other | Maximum
Intangible Assets Liabilities
Finite lived intangible asset/liability, useful life	94 years