Other Assets - Summary of Other Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Benefits receivable related to retrospective reinsurance contracts	$ 37,296	$ 16,317
Reimbursement and fees receivable under TPA service	5,335	7,303
Prepaid expenses	3,376	2,826
Deposits	448	491
Lease acquisition costs, net	671	832
Other	1,572	3,902
Total other assets	$ 48,698	$ 31,671