Investments - Summary of Sales of Available-for-sale Fixed-Maturity Securities (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Schedule of Available-for-sale Securities [Line Items]
Proceeds			$ 17,409	$ 11,694
Fixed-Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds	$ 5,326	$ 200	17,409	11,694
Gross Realized Gains	0	0	0	13
Gross Realized Losses	$ (157)	$ (5)	$ (907)	$ (439)