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LOANS AND ALLOWANCE FOR LOAN LOSSES - Impaired Loans (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Dec. 31, 2017
Unpaid Principal Balance [Abstract] |  |  |  |  |
Unpaid principal balance, total | $ 9,387 |  | $ 9,387 |  | $ 14,094
Recorded Investment [Abstract] |  |  |  |  |
Recorded investment, total | 9,342 |  | 9,342 |  | 13,926
Allowance for loan losses allocated | 1,738 |  | 1,738 |  | 5,937
Average Recorded Investment [Abstract] |  |  |  |  |
Average recorded investment, total | 11,490 | $ 13,273 | 12,303 | $ 12,825 |
Interest Income, Accrual Method [Abstract] |  |  |  |  |
Interest income, accrual method, total | 19 | 51 | 40 | 126 |
Commercial Mortgages | Construction |  |  |  |  |
Unpaid Principal Balance [Abstract] |  |  |  |  |
With no related allowance, Unpaid Principal Balance | 336 |  | 336 |  | 364
Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Recorded Investment | 338 |  | 338 |  | 365
Average Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Average Recorded Investment | 345 | 1,555 | 352 | 1,130 |
Interest Income, Accrual Method [Abstract] |  |  |  |  |
With no related allowance, Interest Income, Accrual Method | 3 | 3 | 6 | 6 |
Commercial Mortgages | Commercial mortgages, other |  |  |  |  |
Unpaid Principal Balance [Abstract] |  |  |  |  |
With no related allowance, Unpaid Principal Balance | 4,366 |  | 4,366 |  | 4,135
With related allowance, Unpaid Principal Balance | 2,173 |  | 2,173 |  | 2,989
Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Recorded Investment | 4,370 |  | 4,370 |  | 4,138
With related allowance, Recorded Investment | 2,139 |  | 2,139 |  | 2,799
Allowance for loan losses allocated | 453 |  | 453 |  | 802
Average Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Average Recorded Investment | 4,290 | 5,879 | 4,240 | 6,538 |
With related allowance, Average Recorded Investment | 2,467 | 4,461 | 2,578 | 3,723 |
Interest Income, Accrual Method [Abstract] |  |  |  |  |
With no related allowance, Interest Income, Accrual Method | 5 | 32 | 10 | 90 |
With related allowance, Interest Income, Accrual Method | 1 | 4 | 3 | 7 |
Residential mortgages |  |  |  |  |
Unpaid Principal Balance [Abstract] |  |  |  |  |
With no related allowance, Unpaid Principal Balance | 439 |  | 439 |  | 450
Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Recorded Investment | 417 |  | 417 |  | 427
Average Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Average Recorded Investment | 421 | 417 | 423 | 410 |
Interest Income, Accrual Method [Abstract] |  |  |  |  |
With no related allowance, Interest Income, Accrual Method | 2 | 2 | 4 | 4 |
Consumer loans: | Home equity lines and loans |  |  |  |  |
Unpaid Principal Balance [Abstract] |  |  |  |  |
With no related allowance, Unpaid Principal Balance | 60 |  | 60 |  | 64
Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Recorded Investment | 61 |  | 61 |  | 64
Average Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Average Recorded Investment | 61 | 71 | 62 | 79 |
With related allowance, Average Recorded Investment | 0 | 180 | 0 | 240 |
Interest Income, Accrual Method [Abstract] |  |  |  |  |
With no related allowance, Interest Income, Accrual Method | 1 | 1 | 2 | 1 |
With related allowance, Interest Income, Accrual Method | 0 | 0 | 0 | 0 |
Commercial and industrial | Commercial and agricultural: |  |  |  |  |
Unpaid Principal Balance [Abstract] |  |  |  |  |
With no related allowance, Unpaid Principal Balance | 643 |  | 643 |  | 861
With related allowance, Unpaid Principal Balance | 1,370 |  | 1,370 |  | 5,231
Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Recorded Investment | 647 |  | 647 |  | 867
With related allowance, Recorded Investment | 1,370 |  | 1,370 |  | 5,266
Allowance for loan losses allocated | 1,285 |  | 1,285 |  | $ 5,135
Average Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Average Recorded Investment | 710 | 626 | 762 | 649 |
With related allowance, Average Recorded Investment | 3,196 | 84 | 3,886 | 56 |
Interest Income, Accrual Method [Abstract] |  |  |  |  |
With no related allowance, Interest Income, Accrual Method | 7 | 8 | 15 | 17 |
With related allowance, Interest Income, Accrual Method | $ 0 | $ 1 | $ 0 | $ 1 |

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