Intangible Assets (Intangible Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 1,674	$ 1,674
Total intangible assets	145,883	186,206
In-place leases
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	105,964	139,548
Accumulated amortization	125,130	91,548
Above-market leases
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	20,453	26,917
Accumulated amortization	19,502	13,038
Below-market ground leases
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net	17,792	18,067
Accumulated amortization	$ 621	$ 345