Summary of Cash, Cash Equivalents and Restricted Cash Reported In Condensed Consolidated Statements of Cash Flows (Detail) - USD ($) $ in Thousands		Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Cash And Cash Equivalents Period Increase Decrease [Abstract]
Cash and cash equivalents		$ 189,743	$ 1,224,490	$ 1,101,230
Restricted cash and cash equivalents	[1]	$ 54,674	$ 54,664	$ 44,659
Restricted Cash and Cash Equivalents, Noncurrent, Statement of Financial Position [Extensible Enumeration]		us-gaap:OtherAssetsNoncurrent	us-gaap:OtherAssetsNoncurrent	us-gaap:OtherAssetsNoncurrent
Total cash, cash equivalents and restricted cash		$ 244,417	$ 1,279,154	$ 1,145,889

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