| **ACQUISITIONS - Narrative (Details) $ / shares in Units, $ in Thousands** |           | 9 Months Ended | 12 Months Ended |
|----------------------------------------------------------------------------|-----------|----------------|-----------------|
||
| **Business Acquisition [Line Items]**                                      |      |           |            |   |
| Cash paid in acquisition                                                   |      | $ 0            | $ 79,324        |   |
| Series A Preferred Stock                                                   |      |           |            |   |
| **Business Acquisition [Line Items]**                                      |      |           |            |   |
| Preferred Stock, issued (in shares) | shares                               |      | 10,000         |            | 10,000 |
| Liquidation value per share (in dollars per share) | $ / shares            |      | $ 2,500        |            | $ 2,500 |
| Preferred Class B                                                          |      |           |            |   |
| **Business Acquisition [Line Items]**                                      |      |           |            |   |
| Entity listing, depository receipt ratio                                   | 0.01      |           |            |   |
| Preferred Class B | Level One                                              |      |           |            |   |
| **Business Acquisition [Line Items]**                                      |      |           |            |   |
| Entity listing, depository receipt ratio                                   | 0.01      |           |            |   |
| Level One                                                                  |      |           |            |   |
| **Business Acquisition [Line Items]**                                      |      |           |            |   |
| Percentage of interest acquired                                            | 100.00%   |           |            |   |
| Number of banking centers | banking_center                                 | 17        |           |            |   |
| Exchange ratio                                                             | 0.7167    |           |            |   |
| Cash payment per share (in dollars per share) | $ / shares                 | $ 10.17   |           |            |   |
| Cash paid in acquisition                                                   | $ 79,300  |           |            |   |
| Other intangibles                                                          | 18,642    |           |            |   |
| Operating revenue                                                          |      |           |            | $ 56,900 |
| Provision expense related to CECL Day 1 adjustments                        |      |           |            | 16,800 |
| Acquisition-related expenses                                               |      |           |            | $ 16,500 |
| Level One | Other Intangible Assets                                        |      |           |            |   |
| **Business Acquisition [Line Items]**                                      |      |           |            |   |
| Other intangibles                                                          | 18,600    |           |            |   |
| Level One | Core Deposits                                                  |      |           |            |   |
| **Business Acquisition [Line Items]**                                      |      |           |            |   |
| Other intangibles                                                          | $ 17,200  |           |            |   |
| Estimated life                                                             | 10 years  |           |            |   |
| Level One | Non-compete                                                    |      |           |            |   |
| **Business Acquisition [Line Items]**                                      |      |           |            |   |
| Other intangibles                                                          | $ 1,400   |           |            |   |
| Estimated life                                                             | 2 years   |           |            |   |
| Level One | Common Stock                                                   |      |           |            |   |
| **Business Acquisition [Line Items]**                                      |      |           |            |   |
| Issuance of common stock related to acquisitions (in shares) | shares      | 5,600,000 |           |            |   |
| Level One | Series A Preferred Stock                                       |      |           |            |   |
| **Business Acquisition [Line Items]**                                      |      |           |            |   |
| Preferred Stock, issued (in shares) | shares                               | 10,000    |           |            |   |
| Dividend rate %                                                            | 7.50%     |           |            |   |
| Liquidation value per share (in dollars per share) | $ / shares            | $ 2,500   |           |            |   |

| X                                                                                                                                                                                                                                                                                      |
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Business Acquisition, Acquisition Related Expenses
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Business Acquisition, Cash Payment, Per Share
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Business Acquisition, Exchange Ratio
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| - Definition
Business Combination, Provision Allowance For Credit Losses - Loans
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| - Definition
Depository Share Interest Ratio
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| - Definition
Number Of Banking Centers
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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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| - Definition
Number of shares of equity interests issued or issuable to acquire entity.
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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
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
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
The percentage rate used to calculate dividend payments on preferred stock.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The per share liquidation preference (or restrictions) of nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) that has a preference in involuntary liquidation considerably in excess of the par or stated value of the shares. The liquidation preference is the difference between the preference in liquidation and the par or stated values of the share.
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| - Definition
Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.
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