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LOANS AND ALLOWANCE FOR LOAN LOSSES - Impaired Loans (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2017 | Sep. 30, 2016 | Dec. 31, 2016
Unpaid Principal Balance [Abstract] |  |  |  |  |
Unpaid principal balance, total | $ 12,194 |  | $ 12,194 |  | $ 12,852
Recorded Investment [Abstract] |  |  |  |  |
Recorded investment, total | 11,092 |  | 11,092 |  | 11,926
Allowance for loan losses allocated | 1,168 |  | 1,168 |  | 876
Average Recorded Investment [Abstract] |  |  |  |  |
Average recorded investment, total | 12,100 | $ 13,434 | 12,391 | $ 14,023 |
Interest Income, Accrual Method [Abstract] |  |  |  |  |
Interest income, accrual method, total | 26 | 79 | 128 | 240 |
Commercial Mortgages | Construction |  |  |  |  |
Unpaid Principal Balance [Abstract] |  |  |  |  |
With no related allowance, Unpaid Principal Balance | 395 |  | 395 |  | 277
Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Recorded Investment | 396 |  | 396 |  | 278
Average Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Average Recorded Investment | 974 | 310 | 946 | 329 |
Interest Income, Accrual Method [Abstract] |  |  |  |  |
With no related allowance, Interest Income, Accrual Method | 3 | 4 | 9 | 11 |
Commercial Mortgages | Commercial mortgages, other |  |  |  |  |
Unpaid Principal Balance [Abstract] |  |  |  |  |
With no related allowance, Unpaid Principal Balance | 4,274 |  | 4,274 |  | 8,792
With related allowance, Unpaid Principal Balance | 5,875 |  | 5,875 |  | 2,245
Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Recorded Investment | 4,277 |  | 4,277 |  | 7,857
With related allowance, Recorded Investment | 4,785 |  | 4,785 |  | 2,247
Allowance for loan losses allocated | 1,009 |  | 1,009 |  | 735
Average Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Average Recorded Investment | 4,946 | 6,124 | 5,973 | 6,760 |
With related allowance, Average Recorded Investment | 4,721 | 5,151 | 3,989 | 4,998 |
Interest Income, Accrual Method [Abstract] |  |  |  |  |
With no related allowance, Interest Income, Accrual Method | 5 | 60 | 73 | 181 |
With related allowance, Interest Income, Accrual Method | 4 | 1 | 10 | 4 |
Residential mortgages |  |  |  |  |
Unpaid Principal Balance [Abstract] |  |  |  |  |
With no related allowance, Unpaid Principal Balance | 457 |  | 457 |  | 395
Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Recorded Investment | 434 |  | 434 |  | 396
Average Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Average Recorded Investment | 439 | 443 | 416 | 358 |
Interest Income, Accrual Method [Abstract] |  |  |  |  |
With no related allowance, Interest Income, Accrual Method | 2 | 2 | 6 | 3 |
Consumer loans: | Home equity lines and loans |  |  |  |  |
Unpaid Principal Balance [Abstract] |  |  |  |  |
With no related allowance, Unpaid Principal Balance | 66 |  | 66 |  | 93
With related allowance, Unpaid Principal Balance | 0 |  | 0 |  | 360
Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Recorded Investment | 67 |  | 67 |  | 95
With related allowance, Recorded Investment | 0 |  | 0 |  | 360
Allowance for loan losses allocated | 0 |  | 0 |  | 141
Average Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Average Recorded Investment | 68 | 101 | 76 | 104 |
With related allowance, Average Recorded Investment | 0 | 360 | 180 | 362 |
Interest Income, Accrual Method [Abstract] |  |  |  |  |
With no related allowance, Interest Income, Accrual Method | 1 | 1 | 2 | 4 |
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 | 714 |  | 714 |  | 690
With related allowance, Unpaid Principal Balance | 413 |  | 413 |  | 0
Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Recorded Investment | 719 |  | 719 |  | 693
With related allowance, Recorded Investment | 414 |  | 414 |  | 0
Allowance for loan losses allocated | 159 |  | 159 |  | $ 0
Average Recorded Investment [Abstract] |  |  |  |  |
With no related allowance, Average Recorded Investment | 661 | 900 | 666 | 1,083 |
With related allowance, Average Recorded Investment | 291 | 45 | 145 | 29 |
Interest Income, Accrual Method [Abstract] |  |  |  |  |
With no related allowance, Interest Income, Accrual Method | 8 | 10 | 24 | 33 |
With related allowance, Interest Income, Accrual Method | $ 3 | $ 1 | $ 4 | $ 4 |

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