Investments - Summary of Sales of Available-for-sale Fixed-Maturity Securities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Proceeds	$ 22,326	$ 11,716	$ 23,055
Fixed-Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds	22,326	11,716	23,055
Gross Realized Gains	7	13	722
Gross Realized Losses	$ (1,036)	$ (442)	$ (35)