Intangible Assets - Summary of Acquired Lease Intangible Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Acquired Finite Lived Intangible Assets [Line Items]
Acquired lease intangible assets, net	$ 49,147	$ 36,365
Acquired lease intangible liabilities, net	(18,147)	(9,130)
In-place lease intangibles
Acquired Finite Lived Intangible Assets [Line Items]
Acquired lease intangible assets, gross	91,760	68,234
Accumulated amortization	(48,126)	(37,648)
Acquired lease intangible assets, net	43,634	30,586
Above Market Leases
Acquired Finite Lived Intangible Assets [Line Items]
Acquired lease intangible assets, gross	10,896	10,191
Accumulated amortization	(5,383)	(4,412)
Acquired lease intangible assets, net	5,513	5,779
Below Market Tenant Leases
Acquired Finite Lived Intangible Assets [Line Items]
Acquired lease intangible liabilities, gross	(23,594)	(12,426)
Accumulated accretion	5,604	3,477
Acquired lease intangible liabilities, net	(17,990)	(8,949)
Above-market ground lease
Acquired Finite Lived Intangible Assets [Line Items]
Acquired lease intangible liabilities, gross	(290)	(290)
Accumulated accretion	133	109
Acquired lease intangible liabilities, net	$ (157)	$ (181)