Losses and Loss Adjustment Expenses - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Claims and claim adjustment expenses prior period development	$ 18,854	$ 40,627	$ 27,637
Claims and claim adjustment expenses overall development	254,579	371,463	$ 227,525
United [Member]
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Claims and claim adjustment expenses overall development	68,339
Flood [Member]
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Preliminary net loss estimated	7,000
Hurricane Ian
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Preliminary gross loss estimated		847,500
Preliminary net loss estimated		65,300
Hurricane Ian | Typ Tap [Member]
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Preliminary gross loss estimated		395,450
Hurricane Ian | HCPCI [Member]
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Preliminary gross loss estimated		$ 452,050
Citizens [Member]
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Claims and claim adjustment expenses overall development	7,875
Short Duration Insurance Contracts Accident Year Two Thousand TwentyTwo And Prior Member
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Claims and claim adjustment expenses prior period development	$ 18,854