The Company and Significant Accounting Policies - Summary of Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents		$ 309,052	$ 170,345
Restricted cash equivalents		39,809	32,531
Cash, cash equivalents, and restricted cash equivalents shown in the statement of cash flows	[1]	$ 348,861	$ 202,876	$ 165,455	$ 164,091

[1] Certain prior period amounts have been revised due to the implementation of ASU 2016-18. See Note 1 for details.