Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 1,674	$ 1,674
Total intangible assets	175,159	186,206
In-place Leases
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	130,277	139,548
Accumulated amortization	100,818	91,548
Above-market Tenant Leases
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	25,209	26,917
Accumulated amortization	14,746	13,038
Below-market Ground Lease
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	17,999	18,067
Accumulated amortization	$ 414	$ 345