Investments - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Schedule of Investments [Line Items]
Available-for-sale debt securities, allowance for credit losses	$ 0		$ 0
Purchase an available-for-sale debt securities with credit deterioration	0
Asset impairments	$ 0	$ 0
Investment [Member] | Issuer Concentration [Member] | Market Value of Total Investment Portfolio [Member]
Schedule of Investments [Line Items]
Investment concentration risk percentage	5.00%