Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 1,674	$ 1,674
Total intangible assets	164,753	186,206
In-place Leases
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	121,619	139,548
Accumulated amortization	109,477	91,548
Above-market Tenant Leases
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	23,531	26,917
Accumulated amortization	16,424	13,038
Below-market Ground Lease
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	17,929	18,067
Accumulated amortization	$ 483	$ 345