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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details) $ in Thousands | 9 Months Ended |
--- | --- | ---
Sep. 30, 2021 USD ($) item | Dec. 31, 2020 USD ($)
Accounting Policies [Line Items] |  |
Number of bank branches | item | 130 |
Number of ATM's | item | 150 |
Goodwill | $ 935,560 | $ 935,560
Accrued interest receivable | 46,200 | 56,700
Available-for-sale Securities |  |
Accounting Policies [Line Items] |  |
Accrued interest receivable | 13,000 | 11,900
Held-to-maturity Securities |  |
Accounting Policies [Line Items] |  |
Accrued interest receivable | $ 5,100 | $ 6,800

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