Reinsurance - Change in Allowance for Credit Losses on Amounts Recoverable from Reinsurers (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Insurance [Abstract]
Balance, beginning of period	$ 372	$ 440
Provision for credit loss expense (benefit)	(12)	(68)
Balance, end of period	$ 360	$ 372