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Loans - Distribution of Fixed Rate Loans and Variable Rate Loans by Portfolio Segment (Detail) - USD ($) $ in Thousands | Jun. 30, 2025 | Dec. 31, 2024
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Consumer Real Estate [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Distribution of fixed rate loans by major loan category, Fixed Rate | $ 281,802 | $ 305,062
Distribution of variable rate loans by major loan category, Variable Rate | 241,979 | 215,052
Agricultural Real Estate [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Distribution of fixed rate loans by major loan category, Fixed Rate | 111,837 | 118,808
Distribution of variable rate loans by major loan category, Variable Rate | 109,167 | 97,593
Agricultural [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Distribution of fixed rate loans by major loan category, Fixed Rate | 47,253 | 54,099
Distribution of variable rate loans by major loan category, Variable Rate | 110,617 | 97,981
Commercial Real Estate [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Distribution of fixed rate loans by major loan category, Fixed Rate | 873,725 | 934,197
Distribution of variable rate loans by major loan category, Variable Rate | 472,228 | 376,614
Commercial and Industrial [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Distribution of fixed rate loans by major loan category, Fixed Rate | 122,192 | 148,542
Distribution of variable rate loans by major loan category, Variable Rate | 171,634 | 126,610
Consumer [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Distribution of fixed rate loans by major loan category, Fixed Rate | 59,319 | 62,977
Distribution of variable rate loans by major loan category, Variable Rate | 29 | 32
Other Loan [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Distribution of fixed rate loans by major loan category, Fixed Rate | 15,098 | 15,270
Distribution of variable rate loans by major loan category, Variable Rate | $ 9,555 | $ 9,708

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