Income Taxes - Summary of Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits, Excluding Interest and Penalties (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 2,589	$ 4,609	$ 5,655
Additions for tax positions of prior years	121	0	304
Settlements for tax positions of prior years	0	(275)	0
Reductions for tax positions of prior years	(2,463)	(1,745)	(1,350)
Balance at end of year	$ 247	$ 2,589	$ 4,609