Allowance for Expected Credit Losses - Premium Receivables and Reinsurance Receivables - Schedule of Allowance for Credit Losses Related to Premium Receivables (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Premiums Receivable
Beginning balance	$ 2,996	$ 2,900
Current period provision for expected credit losses	1,796	1,033
Write-offs	(1,470)	(937)
Ending balance	$ 3,322	$ 2,996