Accumulated Other Comprehensive Income (Loss) - Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other income, net	$ 2,334	$ 4,490	$ 2,980
Benefit from income taxes	(691)	(816)	(389)
Net of tax	272		(5)
Accumulated Net Unrealized Investment Gain (Loss) Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other income, net	272		(5)
Benefit from income taxes	$ 0	$ 0	$ 0