Variable Interest Entities - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Variable Interest Entities [Line Items]
Fixed income securities, amortized cost	$ 289,712	$ 341,685
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	260	643
Available-for-sale Securities	157,020	135,224
Restricted Cash	17,669	11,881	$ 13,612
Assets	8,058,378	8,428,320	7,972,730
Liabilities	6,862,857	6,996,627
Other Investments	28,294	18,317
Derivative assets	0	656
Other assets	92,317	65,817
Accrued interest payable	2,560	0
Derivative liabilities	317	0
Other liabilities	89,036	60,419
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Restricted Cash	47,275	19,223	$ 19,941
Corporate Debt Securities [Member]
Variable Interest Entities [Line Items]
Fixed income securities, amortized cost	92,990	92,694
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	107	262
Available-for-sale Securities	89,192	87,991
Municipal Bonds [Member]
Variable Interest Entities [Line Items]
Fixed income securities, amortized cost	14,646	9,394
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	7	13
Available-for-sale Securities	$ 14,083	$ 8,711