Loans - Collateral-dependent Loans by Class (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 5,858,642	$ 5,884,448
Commercial and Industrial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	745,597	761,167
Commercial Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	3,152,336	3,142,472
Agricultural Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	467,204	489,168
Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	87,336	87,073
Home Equity Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	500,696	484,300
Consumer Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	110,065	117,648
Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	27,519	28,067
Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	767,889	774,553
Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	54,993	61,790
Total | Commercial and Industrial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	23,232	25,698
Total | Commercial Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	27,587	31,164
Total | Agricultural Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	3,291	3,870
Total | Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Total | Home Equity Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	425	425
Total | Consumer Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Total | Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Total | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	458	633
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	37,522	43,034
Real Estate | Commercial and Industrial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	7,101	8,348
Real Estate | Commercial Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	27,096	30,670
Real Estate | Agricultural Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	2,442	2,958
Real Estate | Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Real Estate | Home Equity Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	425	425
Real Estate | Consumer Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Real Estate | Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Real Estate | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	458	633
Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	7,130	7,653
Equipment | Commercial and Industrial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	6,420	6,880
Equipment | Commercial Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	491	494
Equipment | Agricultural Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	219	279
Equipment | Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Equipment | Home Equity Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Equipment | Consumer Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Equipment | Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Equipment | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	400
Accounts Receivable | Commercial and Industrial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	400
Accounts Receivable | Commercial Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Accounts Receivable | Agricultural Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Accounts Receivable | Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Accounts Receivable | Home Equity Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Accounts Receivable | Consumer Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Accounts Receivable | Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Accounts Receivable | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	10,341	10,703
Other | Commercial and Industrial Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	9,711	10,070
Other | Commercial Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Other | Agricultural Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	630	633
Other | Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Other | Home Equity Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Other | Consumer Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Other | Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	0	0
Other | Residential Mortgage Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 0	$ 0