Summary of Cash, Cash Equivalents and Restricted Cash Reported In Condensed Consolidated Statements of Cash Flows (Detail) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Cash And Cash Equivalents Period Increase Decrease [Abstract]
Cash and cash equivalents		$ 83,721	$ 74,423
Restricted cash	[1]	93,971	92,874
Total cash, cash equivalents and restricted cash		$ 177,692	$ 167,297

[1] Restricted cash is included in other assets on the accompanying consolidated balance sheet.