| **Acquisitions and Divestitures - Acquisitions Narrative (Details) $ / shares in Units, $ in Thousands** |           |          |           | 12 Months Ended |
|----------------------------------------------------------------------------------------------------------|-----------|----------|-----------|-----------------|
||
| **Business Acquisition [Line Items]**                                                                    |      |     |      |            |   |   |
| Value of stock issued as a part of acquisition                                                           |      |     |      |                 | $ 70,402 | $ 34,981 |
| Cash paid in acquisition                                                                                 |      |     |      |                 | 14,500 | $ 14,208 |
| Pro forma nonrecurring expense                                                                           |      |     |      |            | $ 12,000 |   |
| Common Stock                                                                                             |      |     |      |            |   |   |
| **Business Acquisition [Line Items]**                                                                    |      |     |      |            |   |   |
| Stock issued as a part of acquisition (in shares) | shares                                               |      |     |      |            | 2,769,568 | 1,574,298 |
| Value of stock issued as a part of acquisition                                                           |      |     |      |            | $ 346 | $ 197 |
| Merger with Ameriana Bancorp                                                                             |      |     |      |            |   |   |
| **Business Acquisition [Line Items]**                                                                    |      |     |      |            |   |   |
| Percentage of interest acquired                                                                          | 100.00%   |     |      |            | 100.00% |   |
| Number of banking centers acquired | bank_branch                                                         | 13        |     |      |            |   |   |
| Stock issued as a part of acquisition (in shares) | shares                                               | 2,800,000 |     |      |            |   |   |
| Value of stock issued as a part of acquisition                                                           | $ 70,400  |     |      |            |   |   |
| Core deposit intangible                                                                                  | $ 5,342   |     |      |            | $ 5,342 |   |
| Acquired intangible asset, expected useful life                                                          | 10 years  |     |      |            |   |   |
| Total purchase price                                                                                     | $ 70,402  |     |      |            | $ 70,402 |   |
| Merger with Ameriana Bancorp | Common Stock                                                              |      |     |      |            |   |   |
| **Business Acquisition [Line Items]**                                                                    |      |     |      |            |   |   |
| Number of shares of common stock                                                                         | 0.9037    |     |      |            | 0.9037 |   |
| Merger with C Financial Corporation                                                                      |      |     |      |            |   |   |
| **Business Acquisition [Line Items]**                                                                    |      |     |      |            |   |   |
| Percentage of interest acquired                                                                          |      | 100.00%  |      |            |   |   |
| Number of banking centers acquired | bank_branch                                                         |      | 6        |      |            |   |   |
| Core deposit intangible                                                                                  |      | $ 981    |      |            |   |   |
| Acquired intangible asset, expected useful life                                                          |      | 10 years |      |            |   |   |
| Total purchase price                                                                                     |      | $ 14,500 |      |            |   |   |
| Cash received by shareholders for each share of common stock held (in dollars per share) | $ / shares    |      | $ 6.738  |      |            |   |   |
| Merger with Community Bancshares, Inc.                                                                   |      |     |      |            |   |   |
| **Business Acquisition [Line Items]**                                                                    |      |     |      |            |   |   |
| Percentage of interest acquired                                                                          |      |     | 100.00%   |            |   |   |
| Number of banking centers acquired | bank_branch                                                         |      |     | 10        |            |   |   |
| Stock issued as a part of acquisition (in shares) | shares                                               |      |     | 1,600,000 |            |   |   |
| Value of stock issued as a part of acquisition                                                           |      |     | $ 35,000  |            |   |   |
| Core deposit intangible                                                                                  |      |     | $ 4,658   |            |   |   |
| Acquired intangible asset, expected useful life                                                          |      |     | 10 years  |            |   |   |
| Total purchase price                                                                                     |      |     | $ 49,189  |            |   |   |
| Share price (in dollars per share) | $ / shares                                                          |      |     | $ 85.94   |            |   |   |
| Cash paid in acquisition                                                                                 |      |     | $ 14,200  |            |   |   |
| Pro forma nonrecurring expense                                                                           |      |     |      |            |   | 1,800 |
| Pro forma revenue                                                                                        |      |     |      |            |   | $ 1,600 |
| Merger with Community Bancshares, Inc. | Common Stock                                                    |      |     |      |            |   |   |
| **Business Acquisition [Line Items]**                                                                    |      |     |      |            |   |   |
| Number of shares of common stock                                                                         |      |     | 4.0926    |            |   |   |

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Business Acquisition, Pro Forma Nonrecurring Expense
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| X                                                                                                                                                                                                                                                                                                                                 |
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Business Combinations, Acquiree, Cash Received For Each Share Currently Owned
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                    |
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| - 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.
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| - Definition
Percentage of voting equity interests acquired at the acquisition date in the business combination.
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| - Definition
Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of identifiable intangible assets recognized as of the acquisition date.
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| - Definition
Amount recognized for assets, including goodwill, in excess of (less than) the aggregate liabilities assumed.
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The number of businesses acquired by the entity during the period.
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| - Definition
The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.
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| - Definition
Number of shares of stock issued during the period pursuant to acquisitions.
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| - Definition
Value of stock issued pursuant to acquisitions during the period.
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