Investments - Summary of Amortized Cost and Fair Value of Investments in Fixed Maturity Securities, Classified as Available-for-Sale (Detail) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Schedule Of Available For Sale Securities [Line Items]
Within one year, Amortized Cost	$ 41,029	$ 23,944
After one year through five years, Amortized Cost	76,260	97,996
After five years through ten years, Amortized Cost	76,895	71,233
After ten years, Amortized Cost	$ 118,986	$ 121,257
Investment, Type [Extensible Enumeration]	Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member]	Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member]
Without single maturity date, Amortized Cost	$ 3,946	$ 4,545
Available-for-sale, Amortized Cost	317,116	318,975
Within one year, Fair Value	40,939	23,806
After one year through five years, Fair Value	75,796	95,500
After five years through ten years, Fair Value	76,076	68,494
After ten years, Fair Value	116,586	115,891
Without single maturity date, Fair value	3,641	4,059
Available-for-sale, Fair Value	$ 313,038	$ 307,750