Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 1,674	$ 1,674
Total intangible assets	146,994	145,883
In-place Leases
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	108,552	105,964
Accumulated amortization	132,512	125,130
Above-market Tenant Leases
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	19,045	20,453
Accumulated amortization	20,910	19,502
Below-market Ground Lease
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	17,723	17,792
Accumulated amortization	$ 690	$ 621