Losses and Loss Adjustment Expenses - Losses and LAE (Detail) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2024		Jun. 30, 2023	Jun. 30, 2024		Jun. 30, 2023
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Net balance, beginning of period*	[1]	$ 273,425		$ 246,051	$ 254,351		$ 246,546
Incurred, net of reinsurance, related to:
Current period		73,506		60,968	153,428		117,666
Prior periods		4,818		922	4,818		4,789
Total incurred, net of reinsurance		78,324		61,890	158,246		122,455
Paid, net of reinsurance, related to:
Current period		(31,771)		(27,105)	(49,560)		(38,215)
Prior periods		(28,193)		(37,250)	(71,252)		(87,200)
Total paid, net of reinsurance		(59,964)		(64,355)	(120,812)		(125,415)
Net balance, end of period		291,785		243,586	291,785		243,586
Add: reinsurance recoverable before allowance for credit losses		279,861		505,369	279,861		505,369
Gross balance, end of period		$ 571,646	[2]	$ 748,955	$ 571,646	[2]	$ 748,955

[1] Net balance represents beginning-of-period liability for unpaid losses and LAE less beginning-of-period reinsurance recoverable for unpaid losses and LAE.

[2] See Note 13 for details of balances associated with consolidated variable interest entity.