| **Core Deposit and Other Intangibles - Schedule of Core Deposit and Other Intangibles (Details) - USD ($) $ in Thousands** | 9 Months Ended | 12 Months Ended |
|----------------------------------------------------------------------------------------------------------------------------|----------------|-----------------|
||
| **Goodwill and Intangible Assets Disclosure [Abstract]**                                                                   |           |            |
| Gross carrying amount                                                                                                      | $ 61,799       | $ 58,360        |
| Core deposit and other intangibles acquired                                                                                |                | 4,181           |
| Accumulated amortization                                                                                                   | (48,097)       | (45,164)        |
| Measurement period adjustment                                                                                              | 2,142          |                 |
| Core deposit and other intangibles reduction                                                                               |                | (742)           |
| Core deposit and other intangibles                                                                                         | $ 15,844       | $ 16,635        |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275
+ Details**Name:**us-gaap_FiniteLivedIntangibleAssetsNet**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of increase (decrease) in carrying value of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.
+ References
No definition available.
+ Details**Name:**us-gaap_FiniteLivedIntangibleAssetsPeriodIncreaseDecrease**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of increase (decrease) to assets, excluding financial assets and goodwill, lacking physical substance with a finite life for purchase accounting adjustments.
+ References
No definition available.
+ Details**Name:**us-gaap_FiniteLivedIntangibleAssetsPurchaseAccountingAdjustments**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.
+ References
No definition available.
+ Details**Name:**us-gaap_FinitelivedIntangibleAssetsAcquired1**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - References
No definition available.
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