Reinsurance - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Insurance [Abstract]
Paid losses recoverable outstanding due date	90 days
Received reinsurance recoveries	$ 16.0	$ 1.4	$ 5.8
Unsecured reinsurance recoverable by reinsurer reporting threshold	1.50%