Reinsurance - Schedule of Unsecured Reinsurance Recoverables from Reinsurers (Detail) - USD ($) $ in Thousands		Dec. 31, 2023	Dec. 31, 2022
Ceded Credit Risk [Line Items]
Total reinsurance recoverables		$ 129,963	$ 125,677
Allowance for credit losses		(360)	$ (372)
Funds withheld and letters of credit related to the above recoverables		(81,520)
Total unsecured amounts recoverable from reinsurers		48,443
Reinsurance Recoverable [Member] | Reinsurer Concentration Risk
Ceded Credit Risk [Line Items]
Total reinsurance recoverables		129,963
Total amounts recoverable from reinsurers		130,323
Allowance for credit losses		(360)
Reinsurance Recoverable [Member] | Reinsurer Concentration Risk | Hannover Reinsurance (Ireland) Limited [Member] | A.M. Best Rating, A+ [Member]
Ceded Credit Risk [Line Items]
Total reinsurance recoverables	[1]	65,045
Reinsurance Recoverable [Member] | Reinsurer Concentration Risk | Arch Reinsurance Company
Ceded Credit Risk [Line Items]
Total reinsurance recoverables	[1]	19,694
Reinsurance Recoverable [Member] | Reinsurer Concentration Risk | Allianz Risk Transfer AG (Bermuda) [Member] | A.M. Best Rating, A+ [Member]
Ceded Credit Risk [Line Items]
Total reinsurance recoverables		9,084
Reinsurance Recoverable [Member] | Reinsurer Concentration Risk | Minnesota Workers' Compensation Reinsurance Association [Member]
Ceded Credit Risk [Line Items]
Total reinsurance recoverables	[1]	8,950
Reinsurance Recoverable [Member] | Reinsurer Concentration Risk | Munich Reinsurance America, Inc [Member]
Ceded Credit Risk [Line Items]
Total reinsurance recoverables	[1]	5,542
Reinsurance Recoverable [Member] | Reinsurer Concentration Risk | Odyssey America Reinsurance Corporation [Member] | A.M. Best Rating, A [Member]
Ceded Credit Risk [Line Items]
Total reinsurance recoverables		4,961
Reinsurance Recoverable [Member] | Reinsurer Concentration Risk | Other Reinsurers [Member]
Ceded Credit Risk [Line Items]
Total reinsurance recoverables		$ 17,047

[1] Current participant in our 2024 reinsurance program.