Income Taxes - Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 27,419	$ 20,483	$ 18,413
Reductions	0	0	0
Reductions	(144)	0	(802)
Settlements	0	0	0
Lapses in statute of limitations	0	0	0
Ending balance	77,410	27,419	20,483
Federal
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Tax positions related to current year, Additions	1,365	2,019	1,206
Tax positions related to prior year, Additions	0	669	0
State
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Tax positions related to current year, Additions	48,493	3,645	1,666
Tax positions related to prior year, Additions	277	603	0
Foreign
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Tax positions related to prior year, Additions	$ 0	$ 0	$ 0