Deferred Policy Acquisition Costs - Schedule of Activity in the Deferred Policy Acquisition Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance, beginning of year	$ 17,810	$ 19,048	$ 19,734
Policy acquisition costs deferred	37,730	40,345	43,872
Amortization expense during the year	(38,481)	(41,583)	(44,558)
Balance, end of year	$ 17,059	$ 17,810	$ 19,048

Amount of amortization expense (reversal of expense) for deferred policy acquisition costs.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration