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LOANS AND ALLOWANCE FOR LOAN LOSSES (Narrative) (Details) $ in Thousands | 3 Months Ended | 6 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | ---
Jun. 30, 2020 USD ($) loan | Jun. 30, 2019 USD ($) loan | Jun. 30, 2020 USD ($) loan | Jun. 30, 2019 USD ($) loan | Dec. 31, 2019 USD ($) | Mar. 31, 2020 USD ($) | Mar. 31, 2019 USD ($) | Dec. 31, 2018 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Loans and Leases Receivable, Related Parties, Description |  |  | At June 30, 2020 and December 31, 2019, outstanding loans to certain officers, directors and their associated companies was less than 5% of the Company's shareholders' equity. |  | At September 30, 2019 and December 31, 2018, outstanding loans to certain officers, directors and their associated companies was less than 5% of the Company's shareholders' equity. |  |  |
Allowance for credit losses | $ 35,539 | $ 26,163 | $ 35,539 | $ 26,163 | $ 25,171 | $ 26,521 | $ 25,201 | $ 24,712
Financing Receivable, Allowance for Credit Loss, Writeoff | (484) | (271) | $ (974) | (607) | (2,713) |  |  |
Other industry exposures |  |  | 0 |  |  |  |  |
Interest lost on nonaccrual loans | 87 | $ 115 | $ 166 | $ 224 |  |  |  |
Recorded Investment | $ 3,431 |  | $ 3,431 |  | 3,629 |  |  |
Loans modified | loan | 0 | 0 | 0 | 0 |  |  |  |
Proceeds from the sale of mortgage loans |  |  | $ 176,250 | $ 79,575 |  |  |  |
Gain on sale of mortgage loans |  |  | 6,095 | $ 1,998 |  |  |  |
Loans held for sale, at fair value (book value of $35,909 and $11,915, respectively) | $ 36,590 |  | 36,590 |  | 11,854 |  |  |
FHLB advances, general debt obligations, pledged collateral | $ 1,300,000 |  | $ 1,300,000 |  | 1,400,000 |  |  |
Financing Receivable, Modifications, Number of Contracts | loan | 0 | 0 | 0 | 0 |  |  |  |
SBA PPP Portfolio Segment |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Allowance for credit losses | $ 113 | $ 0 | $ 113 | $ 0 | 0 | 0 | 0 | 0
Financing Receivable, Allowance for Credit Loss, Writeoff | 0 | 0 | 0 | 0 |  |  |  |
Residential Real Estate |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Allowance for credit losses | 8,603 | 6,249 | 8,603 | 6,249 | 5,842 | 5,897 | 6,153 | 6,071
Financing Receivable, Allowance for Credit Loss, Writeoff | 0 | (14) | (96) | (25) | (462) |  |  |
Mortgage Loans in Process of Foreclosure, Amount | 1,400 |  | 1,400 |  | 1,300 |  |  |
Commercial Real Estate |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Allowance for credit losses | 18,386 | 12,152 | 18,386 | 12,152 | 12,414 | 13,374 | 11,838 | 11,654
Financing Receivable, Allowance for Credit Loss, Writeoff | (21) | 0 | (71) | (65) | (300) |  |  |
Commercial |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Allowance for credit losses | 4,679 | 4,107 | 4,679 | 4,107 | 3,769 | 4,114 | 3,616 | 3,620
Financing Receivable, Allowance for Credit Loss, Writeoff | (420) | (217) | (673) | (453) | (1,167) |  |  |
Home Equity |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Allowance for credit losses | 3,084 | 2,992 | 3,084 | 2,992 | 2,423 | 2,480 | 3,027 | 2,796
Financing Receivable, Allowance for Credit Loss, Writeoff | (17) | (34) | (51) | (44) | (412) |  |  |
Consumer |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Allowance for credit losses | 504 | 383 | 504 | 383 | 507 | 473 | 259 | 234
Financing Receivable, Allowance for Credit Loss, Writeoff | (26) | (6) | (83) | (20) | (301) |  |  |
HPFC Portfolio Segment |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Allowance for credit losses | 170 | 280 | 170 | 280 | 216 | $ 183 | $ 308 | $ 337
Financing Receivable, Allowance for Credit Loss, Writeoff | 0 | 0 | 0 | 0 | (71) |  |  |
Fixed Rate Residential Mortgage |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Proceeds from the sale of mortgage loans | 197,800 | 49,600 | 267,000 | 77,600 |  |  |  |
Gain on sale of mortgage loans | 4,600 | 1,200 | 6,100 | 2,000 |  |  |  |
Loans held for sale, at fair value (book value of $35,909 and $11,915, respectively) | 36,600 |  | 36,600 |  | 11,900 |  |  |
Commercial |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Recorded Investment | 114 |  | 114 |  | 123 |  |  |
Nonoperating Income (Expense) | Fixed Rate Residential Mortgage |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Gain on sale of mortgage loans | $ 1,300 | $ (60) | 742 | $ (64) |  |  |  |
Unrealized gain (loss) on loans held for sale |  |  | $ 681 |  | (61) |  |  |
Minimum |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Number of Months | 18 |  | 18 |  |  |  |  |
Maximum |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Number of Months | 24 |  | 24 |  |  |  |  |
Non-Residential Building Operators Industry Sector | Loan Concentration Risk | Total Loan Portfolio |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Concentration risk (percentage) |  |  | 13.00% |  |  |  |  |
Non-Residential Building Operators Industry Sector | Loan Concentration Risk | Commercial Real Estate |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Concentration risk (percentage) |  |  | 32.00% |  |  |  |  |
Performing | Loans |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Recorded Investment | $ 2,900 |  | $ 2,900 |  | 3,000 |  |  |
Non-performing | Loans |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |
Recorded Investment | $ 555 |  | $ 555 |  | $ 636 |  |  |

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