Allowance for Credit Losses - Additional Information (Detail) - USD ($)	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Jan. 01, 2023
Accounts Notes And Loans Receivable [Line Items]
Increase in allowance for credit losses		$ 5,193,000		$ 4,300,000
Allowance for credit losses	$ 35,280,000			35,280,000		$ 28,511,000
Provision for credit losses	630,000		$ 300,000	$ 2,111,000	$ 1,000,000
Number of days reaching where loans are considered for nonaccrual status				90 days
Conditions where loans are considered for nonaccrual status				A loan may be returned to accruing status only if one of two conditions are met: the loan is well-secured and none of the principal and interest has been past due for a minimum of 90 days or the principal and interest payments are reasonably assured and a sustained period of performance has occurred, generally six months.
Loans modified as troubled debt restructuring	$ 0			$ 0
Individually evaluated loans				greater than $350
Allowance for loan losses recorded for acquired loans				$ 0		$ 0
ASU 2016-13 [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance for credit losses							$ 37,861,000
ASU 2016-13 [Member] | CECL Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance for credit losses							$ 7,682,000
Cumulative Effect, Period of Adoption, Adjustment [Member] | ASU 2016-13 [Member]
Accounts Notes And Loans Receivable [Line Items]
Increase allowance of credit loss				$ 5,193,000