Summary of Cash, Cash Equivalents and Restricted Cash Reported In Condensed Consolidated Statements of Cash Flows (Detail) - USD ($) $ in Thousands		Sep. 30, 2020		Dec. 31, 2019
Cash And Cash Equivalents Period Increase Decrease [Abstract]
Cash and cash equivalents		$ 1,101,230		$ 61,268
Restricted cash and cash equivalents	[1]	$ 44,659		$ 44,399
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		$ 1,145,889	[2]	$ 105,667

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

[2] Consists primarily of short-term cash accounts on which interest is being earned at various annual rates ranging from 0.06% to 0.31%.