Investments (Allowance for Credit Losses of Available-for-Sale Fixed-Maturity Securities) - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) Security
Schedule Of Investments [Line Items]
Credit loss expense - investments | $	$ 0	$ 0	$ 611
Credit loss expense, number of securities | Security			2