Loans - Distribution of Fixed Rate Loans and Variable Rate Loans by Major Loan Category (Detail) $ in Thousands	Mar. 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	$ 320,351
Distribution of variable rate loans by major loan category, Variable Rate	89,769
Agricultural Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by major loan category, Fixed Rate	126,606
Distribution of variable rate loans by major loan category, Variable Rate	69,617
Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by major loan category, Fixed Rate	59,168
Distribution of variable rate loans by major loan category, Variable Rate	81,541
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by major loan category, Fixed Rate	743,845
Distribution of variable rate loans by major loan category, Variable Rate	166,994
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by major loan category, Fixed Rate	120,483
Distribution of variable rate loans by major loan category, Variable Rate	96,435
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by major loan category, Fixed Rate	52,935
Distribution of variable rate loans by major loan category, Variable Rate	4,586
Other Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Distribution of fixed rate loans by major loan category, Fixed Rate	21,671
Distribution of variable rate loans by major loan category, Variable Rate	$ 9,902