| **Acquisitions and Divestitures - Narrative (Details) $ / shares in Units, $ in Thousands, shares in Millions** |          |          | 3 Months Ended | 9 Months Ended | 12 Months Ended |         |
|-----------------------------------------------------------------------------------------------------------------|----------|----------|----------------|----------------|-----------------|---------|
||
| **Business Acquisition [Line Items]**                                                                           |     |     |           |           |            |    |   |
| Cash paid in acquisition                                                                                        |     |     |           | $ 14,500       |            |    |   |
| Common stock issued, value                                                                                      |     |     |           | $ 0            |            |    |   |
| Ameriana Bancorp                                                                                                |     |     |           |           |            |    |   |
| **Business Acquisition [Line Items]**                                                                           |     |     |           |           |            |    |   |
| Share price (in dollars per share) | $ / shares                                                                 |     |     |           |           |            |    | $ 25.13 |
| Merger with C Financial Corporation                                                                             |     |     |           |           |            |    |   |
| **Business Acquisition [Line Items]**                                                                           |     |     |           |           |            |    |   |
| Percentage of interest acquired                                                                                 | 100.00%  |     |           |           |            |    |   |
| Number of banking centers acquired | bank                                                                       | 6        |     |           |           |            |    |   |
| Purchase price                                                                                                  | $ 14,500 |     |           |           |            |    |   |
| Cash received by shareholders for each share of common stock held (usd per share) | $ / shares                  | $ 6.738  |     |           |           |            |    |   |
| Core deposit intangible                                                                                         | $ 981    |     |           |           |            |    |   |
| Acquired intangible asset, expected useful life                                                                 | 10 years |     |           |           |            |    |   |
| Merger with Community Bancshares, Inc.                                                                          |     |     |           |           |            |    |   |
| **Business Acquisition [Line Items]**                                                                           |     |     |           |           |            |    |   |
| Share price (in dollars per share) | $ / shares                                                                 |     | $ 85.94  |           |           |            |    |   |
| Percentage of interest acquired                                                                                 |     | 100.00%  |           |           |            |    |   |
| Number of banking centers acquired | bank                                                                       |     | 10       |           |           |            |    |   |
| Purchase price                                                                                                  |     | $ 49,189 |           |           |            |    |   |
| Core deposit intangible                                                                                         |     | $ 4,658  |           |           |            |    |   |
| Acquired intangible asset, expected useful life                                                                 |     | 10 years |           |           |            |    |   |
| Cash paid in acquisition                                                                                        |     | $ 14,200 |           |           |            |    |   |
| Stock issued as a part of acquisition (in shares) | shares                                                      |     | 1.6      |           |           |            |    |   |
| Common stock issued, value                                                                                      |     | $ 35,000 |           |           |            |    |   |
| Pro forma operating revenue                                                                                     |     |     |           |           | $ 1,600         |    |   |
| Pro forma nonrecurring expense                                                                                  |     |     |           |           | $ 1,800         |    |   |
| Merger with Community Bancshares, Inc. | Common Stock                                                           |     |     |           |           |            |    |   |
| **Business Acquisition [Line Items]**                                                                           |     |     |           |           |            |    |   |
| Number of shares of common stock                                                                                |     | 4.0926   |           |           |            |    |   |
| Merger with CFS Bancorp, Inc. (Citizens)                                                                        |     |     |           |           |            |    |   |
| **Business Acquisition [Line Items]**                                                                           |     |     |           |           |            |    |   |
| Pro forma operating revenue                                                                                     |     |     |           |           |            | $ 4,900 |   |
| Pro forma nonrecurring expense                                                                                  |     |     |           |           |            | $ 9,500 |   |
| Ameriana Bancorp | Forecast                                                                                     |     |     |           |           |            |    |   |
| **Business Acquisition [Line Items]**                                                                           |     |     |           |           |            |    |   |
| Estimated transaction value                                                                                     |     |     | $ 68,800       |           |            |    |   |

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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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Percentage of voting equity interests acquired at the acquisition date in the business combination.
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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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| - Definition
Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.
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The amount of identifiable intangible assets recognized as of the acquisition date.
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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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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.
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Number of shares of stock issued during the period pursuant to acquisitions.
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Value of stock issued pursuant to acquisitions during the period.
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