Summary of Cash, Cash Equivalents and Restricted Cash Reported In Condensed Consolidated Statements of Cash Flows (Detail) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Cash And Cash Equivalents Period Increase Decrease [Abstract]
Cash and cash equivalents		$ 62,726	$ 105,220
Restricted cash and cash equivalents	[1]	$ 94,850	$ 94,465
Restricted Cash and Cash Equivalents, Noncurrent, Asset, Statement of Financial Position [Extensible List]		us-gaap:OtherAssetsMiscellaneousNoncurrent	us-gaap:OtherAssetsMiscellaneousNoncurrent
Total cash, cash equivalents and restricted cash		$ 157,576	$ 199,685

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