| **Accounting for Certain Loans Acquired in a Purchase - Carrying Amount of Loans Included in Balance Sheet (Details) - USD ($) $ in Thousands** | Mar. 31, 2016 | Dec. 31, 2015 |
|-------------------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | $ 914,347     | $ 961,382     |
| Carrying Amount                                                                                                                                 | 870,507       | 917,589       |
| Allowance                                                                                                                                       | 155           | 153           |
| Carrying Amount Net of Allowance                                                                                                                | 870,352       | 917,436       |
| Loans acquired and accounted for under ASC 310-30, outstanding balance                                                                          | 84,500        | 95,800        |
| Loans acquired and accounted for under ASC 310-30, carrying amount                                                                              | 60,100        | 69,600        |
| Commercial and industrial loans                                                                                                                 |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 85,513        | 85,441        |
| Agricultural production financing and other loans to farmers                                                                                    |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 3,735         | 3,049         |
| Real estate loans - Construction                                                                                                                |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 47,885        | 40,991        |
| Real estate loans - Commercial and farmland                                                                                                     |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 392,476       | 425,014       |
| Real estate loans - Residential                                                                                                                 |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 307,326       | 325,141       |
| Real estate loans - Home Equity                                                                                                                 |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 73,364        | 77,053        |
| Individuals' loans for household and other personal expenditures                                                                                |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 2,138         | 2,693         |
| Other commercial loans                                                                                                                          |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 1,910         | 2,000         |
| Ameriana                                                                                                                                        |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 317,927       | 330,918       |
| Carrying Amount                                                                                                                                 | 304,615       | 319,664       |
| Carrying Amount Net of Allowance                                                                                                                | 304,615       | 319,664       |
| Ameriana | Commercial and industrial loans                                                                                                      |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 23,363        | 21,888        |
| Ameriana | Real estate loans - Construction                                                                                                     |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 30,414        | 23,365        |
| Ameriana | Real estate loans - Commercial and farmland                                                                                          |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 131,371       | 144,514       |
| Ameriana | Real estate loans - Residential                                                                                                      |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 116,116       | 123,231       |
| Ameriana | Real estate loans - Home Equity                                                                                                      |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 13,390        | 14,261        |
| Ameriana | Individuals' loans for household and other personal expenditures                                                                     |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 1,433         | 1,731         |
| Ameriana | Other commercial loans                                                                                                               |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 1,840         | 1,928         |
| C Financial                                                                                                                                     |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 94,308        | 99,166        |
| Carrying Amount                                                                                                                                 | 92,097        | 96,829        |
| Carrying Amount Net of Allowance                                                                                                                | 92,097        | 96,829        |
| C Financial | Commercial and industrial loans                                                                                                   |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 99            | 104           |
| C Financial | Real estate loans - Construction                                                                                                  |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 6,928         | 6,214         |
| C Financial | Real estate loans - Commercial and farmland                                                                                       |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 25,729        | 27,838        |
| C Financial | Real estate loans - Residential                                                                                                   |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 52,720        | 55,856        |
| C Financial | Real estate loans - Home Equity                                                                                                   |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 8,824         | 9,144         |
| C Financial | Individuals' loans for household and other personal expenditures                                                                  |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 8             | 10            |
| Community                                                                                                                                       |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 93,530        | 99,541        |
| Carrying Amount                                                                                                                                 | 87,523        | 93,355        |
| Allowance                                                                                                                                       | 105           | 4             |
| Carrying Amount Net of Allowance                                                                                                                | 87,418        | 93,351        |
| Community | Commercial and industrial loans                                                                                                     |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 7,224         | 6,769         |
| Community | Agricultural production financing and other loans to farmers                                                                        |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 2,472         | 1,761         |
| Community | Real estate loans - Construction                                                                                                    |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 9,681         | 10,436        |
| Community | Real estate loans - Commercial and farmland                                                                                         |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 47,190        | 49,997        |
| Community | Real estate loans - Residential                                                                                                     |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 19,212        | 21,886        |
| Community | Real estate loans - Home Equity                                                                                                     |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 7,445         | 8,231         |
| Community | Individuals' loans for household and other personal expenditures                                                                    |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 306           | 461           |
| CFS                                                                                                                                             |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 371,786       | 393,014       |
| Carrying Amount                                                                                                                                 | 353,882       | 373,649       |
| Allowance                                                                                                                                       | 50            | 149           |
| Carrying Amount Net of Allowance                                                                                                                | 353,832       | 373,500       |
| CFS | Commercial and industrial loans                                                                                                           |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 50,476        | 52,060        |
| CFS | Real estate loans - Construction                                                                                                          |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 862           | 976           |
| CFS | Real estate loans - Commercial and farmland                                                                                               |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 175,692       | 189,372       |
| CFS | Real estate loans - Residential                                                                                                           |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 113,633       | 118,105       |
| CFS | Real estate loans - Home Equity                                                                                                           |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 30,705        | 31,986        |
| CFS | Individuals' loans for household and other personal expenditures                                                                          |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 348           | 443           |
| CFS | Other commercial loans                                                                                                                    |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 70            | 72            |
| SCB                                                                                                                                             |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 36,796        | 38,743        |
| Carrying Amount                                                                                                                                 | 32,390        | 34,092        |
| Carrying Amount Net of Allowance                                                                                                                | 32,390        | 34,092        |
| SCB | Commercial and industrial loans                                                                                                           |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 4,351         | 4,620         |
| SCB | Agricultural production financing and other loans to farmers                                                                              |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 1,263         | 1,288         |
| SCB | Real estate loans - Commercial and farmland                                                                                               |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 12,494        | 13,293        |
| SCB | Real estate loans - Residential                                                                                                           |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 5,645         | 6,063         |
| SCB | Real estate loans - Home Equity                                                                                                           |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | 13,000        | 13,431        |
| SCB | Individuals' loans for household and other personal expenditures                                                                          |          |          |
| **Accounts, Notes, Loans and Financing Receivable [Line Items]**                                                                                |          |          |
| Loans Acquired                                                                                                                                  | $ 43          | $ 48          |

| X                                                                                                                                                                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Allowance for Loan Losses
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| - Definition
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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.
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| - Definition
The recorded balance, net of any applicable reductions (for example, unamortized accretable yield and other-than-temporary impairments), for loans accounted for as debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.
+ References
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| - Definition
The undiscounted sum of all amounts, including amounts deemed principal, interest, fees, penalties, and other under the loan, owed to the investor at the reporting date, whether or not currently due and whether or not any such amounts have been written or charged off by the investor.  This relates to loans accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.
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| - Definition
The recorded balance, net of any applicable reductions (for example, unamortized accretable yield and allowance for loan losses).  This relates to loans not accounted for debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.
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| - Definition
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