Losses and Loss Adjustment Expenses - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Claims and claim adjustment expenses prior period development	$ 8,105	$ 13,308	$ 12,894	$ 24,318
Total incurred, net of reinsurance	66,726	139,794	189,181	$ 299,328
Hurricane [Member]
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Total incurred, net of reinsurance		$ 65,000
United [Member]
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Total incurred, net of reinsurance	16,225		51,560
Accident Year 2022 and Prior [Member]
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Claims and claim adjustment expenses prior period development	$ 8,105		$ 12,894