Deferred Policy Acquisition Costs - Schedule of Activity in Deferred Policy Acquisition Costs (DPAC) (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Beginning Balance	$ 64,367	$ 63,906	$ 64,544	$ 63,204
Policy acquisition costs deferred, net of ceding commission	45,510	43,146	90,845	88,961
Amortization	(40,956)	(36,112)	(86,468)	(81,225)
Ending Balance	$ 68,921	$ 70,940	$ 68,921	$ 70,940

Amount of amortization expense (reversal of expense) for deferred policy acquisition costs.

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+ Details

- Definition

Amount of deferred policy acquisition cost capitalized on contract remaining in force.

+ References + Details