Loans and Allowance for Credit Losses - Additional Information (Details)	3 Months Ended
	Mar. 31, 2024 USD ($) Loan_modified Alternative	Mar. 31, 2023 USD ($) Loan_modified	Dec. 31, 2023 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest on loans	$ 31,300,000		$ 29,900,000
Minimum value of loans individually measured for impairment	$ 250,000,000
Number of alternatives for measuring impaired loans receivable | Alternative	3
Interest lost on nonaccrual loans	$ 267,000	$ 79,000
Troubled debt restructurings balance | Loan_modified	0	0
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt coverage ratio	1.20x
Commercial Real Estate | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum loan-to-value ratio (in hundredths)	65.00%
Amortization period of loans	twenty
Commercial Real Estate | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum loan-to-value ratio (in hundredths)	80.00%
Amortization period of loans	twenty five years
1-4 Family Residential Properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period when loans charged-down	180 days
Non-residential Buildings
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 1,060,000,000.00
Residential Buildings and Dwellings
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 549,300,000
Unsecured Open-end Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period when loans charged-down	180 days
Other Secured Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period when loans charged-down	120 days
Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 602,900,000		588,500,000
Increase in accounts and notes receivable	$ 14,400,000
Maximum loan-to-value ratio (in hundredths)	65.00%
Amortization period of loans	twenty-five years
Loans receivable, time period	1 year
Agricultural | Corn and Other Grain Farming
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 488,500,000		$ 472,500,000
Increase in accounts and notes receivable	$ 16,000,000
Commercial and Industrial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum loan-to-value ratio (in hundredths)	80.00%
Amortization period of loans	seven years
Loans receivable, time period	1 year
Residential Properties | Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum loan-to-value ratio (in hundredths)	80.00%
Amortization period of loans	twenty-five years