Allowance for Credit Losses - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2023
Accounts Notes And Loans Receivable [Line Items]
Provision for credit losses		$ 5,364,000	$ 4,435,000	$ 1,752,000
Allowance for credit losses		5,885,000	4,435,000	1,752,000
Non-accrual status and partial charge-offs		16,600,000
Allowance for loan losses				28,511,000
Allowance for credit losses		$ 39,669,000	37,160,000	28,511,000	$ 26,641,000
Provision for loan losses				1,752,000	830,000
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 three 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; the borrower has made a minimum of six months payments; or the principal and interest payments are reasonably assured and a sustained period of performance has occurred, generally six months.
Financing receivable, nonaccrual loans, gross interest income		$ 657,000	446,000	384,000
Interest income on nonaccrual loans recognized on cash basis		256,000	343,000	451,000
Foreclosed assets		0	0
Residential mortgages in process of foreclosure		$ 669,000	1,018,000
Individually evaluated loans		greater than $350
Loans modified as troubled debt restructuring		$ 0	$ 0	0
Maximum [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value of servicing rights prepayment speed		7.30%	11.00%
Minimum [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value of servicing rights prepayment speed		13.94%	4.60%
ASU 2016-13 [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance for loan losses						$ 37,861,000
Allowance for credit losses				897,000
CECL Loans [Member] | ASU 2016-13 [Member]
Accounts Notes And Loans Receivable [Line Items]
Allowance for loan losses						$ 7,682,000
Allowance for credit losses				$ 4,296,000
Adjustment [Member] | ASU 2016-13 [Member]
Accounts Notes And Loans Receivable [Line Items]
Increase allowance of credit loss	$ 897,000
Adjustment [Member] | CECL Loans [Member] | ASU 2016-13 [Member]
Accounts Notes And Loans Receivable [Line Items]
Increase allowance of credit loss	$ 4,296,000
Civista Leasing And Finance [Member]
Accounts Notes And Loans Receivable [Line Items]
Provision for loan losses					$ 452,000