Accumulated Other Comprehensive Income (Loss) - Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other income, net	$ 379	$ 1,261	$ 1,970	$ 3,297
Benefit from income taxes	(132)	$ (330)	(436)	$ (650)
Net of tax	66		126
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	$ 66		$ 126