Acquired In-Place Leases and Above/Below Market Leases Summary of Acquired Lease Intangibles (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets, Gross [Abstract]
Acquired lease intangible assets	$ 1,178	$ 2,088
Net of accumulated amortization of other intangible assets	(1,115)	(1,128)
Below Market Lease [Abstract]
Below market leases	67,423	66,521
Accumulated accretion	(37,241)	(33,073)
Acquired lease intangible liabilities, net	30,182	33,448
In-place leases
Finite-Lived Intangible Assets, Gross [Abstract]
Acquired lease intangible assets	54,206	48,741
Net of accumulated amortization of other intangible assets	(45,835)	(38,906)
Acquired lease intangible assets, net	8,371
Above market leases
Finite-Lived Intangible Assets, Gross [Abstract]
Acquired lease intangible assets	21,262	21,667
Net of accumulated amortization of other intangible assets	(20,084)	(19,579)
Acquired lease intangible assets, net	1,178
Acquired lease intangible assets
Finite-Lived Intangible Assets, Gross [Abstract]
Acquired lease intangible assets, net	$ 9,549	$ 11,923