Summary of Significant Accounting Policies - Summary of Cash and Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Cash and cash equivalents	$ 13,639	$ 20,460	$ 16,062	$ 22,491
Restricted cash	14,882	11,656	11,208	9,111
Total cash, cash equivalents and restricted cash	$ 28,521	$ 32,116	$ 27,270	$ 31,602