Commitments, Contingencies and Off-Balance-Sheet Risk - Contractual Amounts of Financial Instruments with Off-Balance-Sheet Risk (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fixed Rate	$ 63,795	$ 43,154
Variable Rate	738,214	644,997
Lines of Credit and Construction Loans [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fixed Rate	62,910	42,184
Variable Rate	692,184	599,185
Overdraft Protection [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fixed Rate	10	10
Variable Rate	45,606	45,182
Letters of Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fixed Rate	875	960
Variable Rate	$ 424	$ 630