| **Loans and Allowance - Summary of Non-Accrual Loans by Loan Class (Details) - USD ($) $ in Thousands** | Jun. 30, 2020 | Dec. 31, 2019 |
|---------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                        |          |          |
| Non-accrual loans                                                                                       | $ 50,102      | $ 15,949      |
| Commercial and industrial loans                                                                         |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                        |          |          |
| Non-accrual loans                                                                                       | 16,354        | 1,255         |
| Agricultural production financing and other loans to farmers                                            |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                        |          |          |
| Non-accrual loans                                                                                       | 0             | 183           |
| Construction                                                                                            |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                        |          |          |
| Non-accrual loans                                                                                       | 119           | 977           |
| Commercial and farmland                                                                                 |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                        |          |          |
| Non-accrual loans                                                                                       | 25,405        | 7,007         |
| Residential                                                                                             |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                        |          |          |
| Non-accrual loans                                                                                       | 5,773         | 5,062         |
| Home equity                                                                                             |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                        |          |          |
| Non-accrual loans                                                                                       | 2,376         | 1,421         |
| Individuals' loans for household and other personal expenditures                                        |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                        |          |          |
| Non-accrual loans                                                                                       | $ 75          | $ 44          |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of financing receivable on nonaccrual status.
+ References
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