Investment Securities - Summary of Amortized Cost and Estimated Market Value of Investment Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Available-for-sale Securities, Debt Maturities [Abstract]
Amortized Cost, due in one year or less	$ 1,613
Amortized Cost, due after one year through five years	7,692
Amortized Cost, due after five years through ten years	9,426
Amortized Cost, due after ten years	35,728
Amortized Cost	54,459	$ 44,494
Market Value, due in one year or less	1,600
Market Value, due after one year through five years	7,389
Market Value, due after five years through ten years	8,172
Market Value, due after ten years	31,193
Market Value, total	$ 48,354	$ 44,772