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LOANS AND ALLOWANCE FOR LOAN LOSSES - Troubled Debt Restructuring (Details) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 USD ($) loan | Sep. 30, 2020 USD ($) borrower | Sep. 30, 2021 USD ($) loan borrower | Sep. 30, 2020 USD ($) borrower
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Number of Loans | 2 | 3 | 6 | 15
Pre-Modification Outstanding Recorded Investment | $ 502,000 | $ 1,458,000 | $ 6,596,000 | $ 5,100,000
Post-Modification Outstanding Recorded Investment | 502,000 | 1,458,000 | 6,596,000 | 5,100,000
Allowance for loan and lease losses, period increase (decrease) | 200,000 |  | 1,900,000 | 100,000
Financing receivables, impaired, troubled debt restructuring, write-down | $ 0 | $ 0 | $ 0 | $ 0
Commercial and agricultural: | Commercial and industrial |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Number of Loans | 2 | 2 | 2 | 4
Pre-Modification Outstanding Recorded Investment | $ 502,000 | $ 1,138,000 | $ 502,000 | $ 2,068,000
Post-Modification Outstanding Recorded Investment | $ 502,000 | $ 1,138,000 | $ 502,000 | $ 2,068,000
Commercial and agricultural: | Commercial mortgages |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Number of Loans | borrower |  |  | 2 |
Residential mortgages |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Number of Loans | borrower |  | 1 |  | 4
Pre-Modification Outstanding Recorded Investment |  | $ 320,000 |  | $ 997,000
Post-Modification Outstanding Recorded Investment |  | $ 320,000 |  | $ 997,000
Commercial mortgages: | Commercial mortgages |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Number of Loans |  |  | 4 | 4
Pre-Modification Outstanding Recorded Investment |  |  | $ 6,094,000 | $ 1,297,000
Post-Modification Outstanding Recorded Investment |  |  | $ 6,094,000 | $ 1,297,000
Consumer loans: | Home equity lines and loans |  |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |  |
Number of Loans | borrower |  |  |  | 3
Pre-Modification Outstanding Recorded Investment |  |  |  | $ 738,000
Post-Modification Outstanding Recorded Investment |  |  |  | $ 738,000

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