| **OTHER INTANGIBLES - Narrative (Details) - USD ($) $ in Thousands** | 3 Months Ended | 9 Months Ended |          |         |
|----------------------------------------------------------------------|----------------|----------------|----------|---------|
||
| **Indefinite-lived Intangible Assets [Line Items]**                  |           |           |     |    |   |   |
| Intangible asset amortization                                        | $ 2,303        | $ 1,463        | $ 5,972  | $ 4,284 |   |   |
| Minimum                                                              |           |           |     |    |   |   |
| **Indefinite-lived Intangible Assets [Line Items]**                  |           |           |     |    |   |   |
| Useful life of core deposit intangibles and other intangibles        |           |           | 2 years  |    |   |   |
| Maximum                                                              |           |           |     |    |   |   |
| **Indefinite-lived Intangible Assets [Line Items]**                  |           |           |     |    |   |   |
| Useful life of core deposit intangibles and other intangibles        |           |           | 10 years |    |   |   |
| Level One                                                            |           |           |     |    |   |   |
| **Indefinite-lived Intangible Assets [Line Items]**                  |           |           |     |    |   |   |
| Other intangibles                                                    |           |           |     |    | $ 18,642 |   |
| Level One | Core Deposits                                            |           |           |     |    |   |   |
| **Indefinite-lived Intangible Assets [Line Items]**                  |           |           |     |    |   |   |
| Other intangibles                                                    |           |           |     |    | 17,200 |   |
| Level One | Non-compete                                              |           |           |     |    |   |   |
| **Indefinite-lived Intangible Assets [Line Items]**                  |           |           |     |    |   |   |
| Other intangibles                                                    |           |           |     |    | $ 1,400 |   |
| Hoosier                                                              |           |           |     |    |   |   |
| **Indefinite-lived Intangible Assets [Line Items]**                  |           |           |     |    |   |   |
| Other intangibles                                                    |           |           |     |    |   | $ 2,247 |
| Hoosier | Customer Relationships                                     |           |           |     |    |   |   |
| **Indefinite-lived Intangible Assets [Line Items]**                  |           |           |     |    |   |   |
| Other intangibles                                                    |           |           |     |    |   | $ 2,200 |

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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of identifiable intangible assets recognized as of the acquisition date.
+ References
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| - Definition
Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
+ References
No definition available.
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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.
+ References
No definition available.
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