Reinsurance - Change in Allowance for Credit Losses on Amounts Recoverable from Reinsurers (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Insurance [Abstract]
Balance, beginning of period	$ 452	$ 444
Provision for credit loss expense (benefit)	(12)	8
Balance, end of period	$ 440	$ 452