Fair Value of Assets and Liabilities - Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Net change in unrealized losses on investments, net of tax	$ (1,500)	$ 141	$ (27)	$ (4,600)	$ 1,000