Loans - Distribution of Fixed Rate Loans and Variable Rate Loans by Major Loan Category (Detail) $ in Thousands	Dec. 31, 2022 USD ($)
Consumer Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by major loan category, Fixed Rate	$ 354,420
Distribution of variable rate loans by major loan category, Variable Rate	140,003
Agricultural Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by major loan category, Fixed Rate	144,702
Distribution of variable rate loans by major loan category, Variable Rate	76,117
Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by major loan category, Fixed Rate	52,867
Distribution of variable rate loans by major loan category, Variable Rate	75,866
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by major loan category, Fixed Rate	941,927
Distribution of variable rate loans by major loan category, Variable Rate	210,676
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by major loan category, Fixed Rate	130,513
Distribution of variable rate loans by major loan category, Variable Rate	111,847
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by major loan category, Fixed Rate	88,972
Distribution of variable rate loans by major loan category, Variable Rate	175
Other Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by major loan category, Fixed Rate	20,029
Distribution of variable rate loans by major loan category, Variable Rate	$ 9,789