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LOANS AND ALLOWANCE FOR CREDIT LOSSES - Narrative (Details) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2021 USD ($) contract | Mar. 31, 2020 USD ($) contract | Dec. 31, 2020 USD ($) contract
Financing Receivable Allowance For Credit Losses [Line Items] |  |  |
Allowance for credit losses provision | $ 0 | $ 1,400,000 |
Loan basis points | 0.42% |  | 0.55%
Percentage of loan growth excluding PPP loans | 1.60% |  |
Loans classified in doubtful or loss risk rating | $ 0 |  | $ 0
Number of loans modified as TDRs | contract | 1 | 0 | 4
Increase in allowance for loan losses due to TDRs | $ 0 |  | $ 0
Troubled debt restructuring charge-offs | $ 0 |  | 0
COVID-19 |  |  |
Financing Receivable Allowance For Credit Losses [Line Items] |  |  |
Allowance for credit losses provision |  |  | $ 13,200,000

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