v3.26.3
Loans - Contractual Aging at Amortized Cost in Past Due Loans by Portfolio Segment (Detail) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due $ 2,738,954 $ 2,713,470
Total Financing Receivables 2,737,319 2,711,959
30 to 59 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 4,530 4,306
60 to 89 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 757 2,398
Greater Than 90 Days [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 4,375 1,170
Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 9,662 7,874
Current [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 2,727,657 2,704,085
Consumer Real Estate [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 548,913 526,439
Total Financing Receivables 549,582 527,043
Consumer Real Estate [Member] | 30 to 59 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 4,244 3,536
Consumer Real Estate [Member] | 60 to 89 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 466 919
Consumer Real Estate [Member] | Greater Than 90 Days [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 812 766
Consumer Real Estate [Member] | Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 5,522 5,221
Consumer Real Estate [Member] | Current [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 544,060 521,822
Agricultural Real Estate [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 210,321 217,034
Total Financing Receivables 210,139 216,830
Agricultural Real Estate [Member] | 30 to 59 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 0 516
Agricultural Real Estate [Member] | 60 to 89 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 0 0
Agricultural Real Estate [Member] | Greater Than 90 Days [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 3,444 130
Agricultural Real Estate [Member] | Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 3,444 646
Agricultural Real Estate [Member] | Current [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 206,695 216,184
Agricultural [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 245,639 218,050
Total Financing Receivables 245,973 218,345
Agricultural [Member] | 30 to 59 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 0 0
Agricultural [Member] | 60 to 89 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 0 1,444
Agricultural [Member] | Greater Than 90 Days [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 110 50
Agricultural [Member] | Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 110 1,494
Agricultural [Member] | Current [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 245,863 216,851
Commercial Real Estate [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 1,321,021 1,355,571
Total Financing Receivables 1,318,393 1,353,019
Commercial Real Estate [Member] | 30 to 59 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 0 56
Commercial Real Estate [Member] | 60 to 89 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 0 0
Commercial Real Estate [Member] | Greater Than 90 Days [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 0 141
Commercial Real Estate [Member] | Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 0 197
Commercial Real Estate [Member] | Current [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 1,318,393 1,352,822
Commercial and Industrial [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Financing Receivables 343,349 314,096
Commercial and Industrial [Member] | 30 to 59 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 133 0
Commercial and Industrial [Member] | 60 to 89 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 169 0
Commercial and Industrial [Member] | Greater Than 90 Days [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 0 0
Commercial and Industrial [Member] | Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 302 0
Commercial and Industrial [Member] | Current [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 343,047 314,096
Consumer [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 47,251 58,838
Total Financing Receivables 47,794 59,493
Consumer [Member] | 30 to 59 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 153 198
Consumer [Member] | 60 to 89 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 122 35
Consumer [Member] | Greater Than 90 Days [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 9 83
Consumer [Member] | Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 284 316
Consumer [Member] | Current [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 47,510 59,177
Other Loan [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 22,089 23,133
Total Financing Receivables 22,089 23,133
Other Loan [Member] | 30 to 59 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 0 0
Other Loan [Member] | 60 to 89 Days Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 0 0
Other Loan [Member] | Greater Than 90 Days [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 0 0
Other Loan [Member] | Past Due [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due 0 0
Other Loan [Member] | Current [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total Past Due $ 22,089 $ 23,133