| **Other Intangibles - Schedule of Core Deposit and Other Intangibles (Details) - USD ($) $ in Thousands** | 9 Months Ended | 12 Months Ended |
|-----------------------------------------------------------------------------------------------------------|----------------|-----------------|
||
| **Acquired Finite-Lived Intangible Assets [Line Items]**                                                  |           |            |
| Gross carrying amount                                                                                     | $ 85,869       | $ 63,940        |
| Accumulated amortization                                                                                  | (59,815)       | (54,721)        |
| Total other intangibles                                                                                   | 26,054         | 31,148          |
| Core deposit intangibles acquired                                                                         |           |            |
| **Acquired Finite-Lived Intangible Assets [Line Items]**                                                  |           |            |
| Intangibles acquired                                                                                      |                | 18,164          |
| Other intangibles                                                                                         |           |            |
| **Acquired Finite-Lived Intangible Assets [Line Items]**                                                  |           |            |
| Intangibles acquired                                                                                      |                | $ 3,765         |

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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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+ References
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| - Definition
Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.
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| - Definition
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Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.
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