Loans and Allowance for Credit Losses - Modified Payment Status (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	$ 12,165	$ 10,471
Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	12,165	10,471
Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Residential real estate [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	1,017	758
Residential real estate [Member] | Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	1,017	758
Residential real estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Residential real estate [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Residential real estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Residential real estate [Member] | Senior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	987	758
Residential real estate [Member] | Senior Lien | Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	987	758
Residential real estate [Member] | Senior Lien | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Residential real estate [Member] | Senior Lien | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Residential real estate [Member] | Senior Lien | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Residential real estate [Member] | Junior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	30
Residential real estate [Member] | Junior Lien | Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	30
Residential real estate [Member] | Junior Lien | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0
Residential real estate [Member] | Junior Lien | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0
Residential real estate [Member] | Junior Lien | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0
Commercial, financial, agricultural and other [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	1,288	50
Commercial, financial, agricultural and other [Member] | Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	1,288	50
Commercial, financial, agricultural and other [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Commercial, financial, agricultural and other [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Commercial, financial, agricultural and other [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Commercial, financial, agricultural and other [Member] | Equipment Finance
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	171
Commercial, financial, agricultural and other [Member] | Equipment Finance | Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	171
Commercial, financial, agricultural and other [Member] | Equipment Finance | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0
Commercial, financial, agricultural and other [Member] | Equipment Finance | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0
Commercial, financial, agricultural and other [Member] | Equipment Finance | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0
Commercial, financial, agricultural and other [Member] | Time and Demand Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	1,117	50
Commercial, financial, agricultural and other [Member] | Time and Demand Loans | Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	1,117	50
Commercial, financial, agricultural and other [Member] | Time and Demand Loans | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Commercial, financial, agricultural and other [Member] | Time and Demand Loans | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Commercial, financial, agricultural and other [Member] | Time and Demand Loans | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Commercial Real Estate [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	9,823	9,663
Commercial Real Estate [Member] | Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	9,823	9,663
Commercial Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Commercial Real Estate [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Commercial Real Estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Commercial Real Estate [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	9,823	9,663
Commercial Real Estate [Member] | Owner Occupied Commercial Real Estate | Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	9,823	9,663
Commercial Real Estate [Member] | Owner Occupied Commercial Real Estate | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Commercial Real Estate [Member] | Owner Occupied Commercial Real Estate | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	0
Commercial Real Estate [Member] | Owner Occupied Commercial Real Estate | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0	$ 0
Loans to individuals [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	37
Loans to individuals [Member] | Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	37
Loans to individuals [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0
Loans to individuals [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0
Loans to individuals [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0
Loans to individuals [Member] | Automobile Loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	37
Loans to individuals [Member] | Automobile Loan | Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	37
Loans to individuals [Member] | Automobile Loan | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0
Loans to individuals [Member] | Automobile Loan | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	0
Loans to individuals [Member] | Automobile Loan | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2	$ 0