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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details) $ in Thousands | 4 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Apr. 30, 2022 USD ($) | Dec. 31, 2022 USD ($) segment | Jun. 30, 2022 USD ($) segment | Dec. 31, 2022 USD ($) item | Dec. 31, 2021 USD ($)
Accounting Policies [Line Items] |  |  |  |  |
Number of bank branches | item |  |  |  | 114 |
Number of ATM's | item |  |  |  | 130 |
Number of operating segments | segment |  | 2 | 1 |  |
Accruals for uncertain tax positions |  | $ 0 |  | $ 0 | $ 0
Impairment charges for goodwill | $ 0 |  | $ 0 | 0 |
Available for sale securities, allowance for credit losses |  | 0 |  | 0 |
Goodwill |  | 925,211 |  | 925,211 | 935,560
Loans held for investment, accrued interest receivable |  | $ 58,900 |  | $ 58,900 | 43,300
Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] |  | Other Assets |  | Other Assets |
HTM securities, Accrued interest receivable |  | $ 8,600 |  | $ 8,600 | 7,000
Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] |  | Other Assets |  | Other Assets |
AFS securities, accrued interest receivable |  | $ 14,200 |  | $ 14,200 | $ 14,500
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] |  | Other Assets |  | Other Assets |
Restricted equity securities as a percentage of outstanding borrowings, required by FHLB |  |  |  | 4.25% | 3.75%
Restricted equity securities as a percentage of outstanding borrowings, required by FRB |  |  |  | 6.00% | 6.00%
Debt security, duration to be placed in nonaccrual status |  |  |  | 90 days |
ALLL, reasonable and supportable forecast period |  |  |  | 2 years |
Commercial and consumer loans on nonaccrual status, period |  |  |  | 90 days |
Liabilities for post retirement benefits payable to other beneficiaries |  | $ 13,300 |  | $ 13,300 | $ 14,900
Minimum |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |
Intangible assets, amortization period (years) |  |  |  | 4 years |
Period past due to change TDR status |  |  |  | 30 days |
Estimated useful life of bank premises |  |  |  | 3 years |
Percentage of fair value of the derivative instruments for the hedge to be highly effective |  |  |  | 80.00% |
Maximum |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |
Intangible assets, amortization period (years) |  |  |  | 10 years |
Estimated useful life of bank premises |  |  |  | 40 years |
Percentage of fair value of the derivative instruments for the hedge to be highly effective |  |  |  | 125.00% |
Non-real Estate Secured Loans [Member] |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |
Consumer loans, period for past due status |  | 120 days |  | 120 days |
Real Estate Secured Loans [Member] |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |
Consumer loans, period for past due status |  | 180 days |  | 180 days |

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