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LOANS AND ALLOWANCE FOR LOAN LOSSES - Allowances (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Dec. 31, 2017 | Jun. 30, 2018 | Dec. 31, 2017
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |  |
Beginning balance | $ 21,390 | $ 14,960 | $ 21,161 | $ 14,253 | $ 14,253 |  |
Charge-offs | (4,303) | (447) | (4,875) | (892) |  |  |
Recoveries | 196 | 170 | 288 | 282 |  |  |
Net recoveries (charge-offs) | (4,107) | (277) | (4,587) | (610) |  |  |
Provision | 2,362 | 421 | 3,071 | 1,461 |  |  |
Ending balance | 19,645 | 15,104 | 19,645 | 15,104 | 21,161 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  | $ 1,738 | $ 5,937
Collectively evaluated for impairment |  |  |  |  |  | 17,907 | 15,195
Total ending allowance balance | 21,390 | 14,960 | 21,161 | 14,253 | 14,253 | 19,645 | 21,161
Loans [Abstract] |  |  |  |  |  |  |
Loans individually evaluated for impairment |  |  |  |  |  | 9,342 | 13,926
Loans collectively evaluated for impairment |  |  |  |  |  | 1,328,768 | 1,300,864
Total recorded investment in loans |  |  |  |  |  | 1,338,110 | 1,315,582
Loans acquired with deteriorated credit quality |  |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |  |
Beginning balance |  |  | 29 |  |  |  |
Ending balance |  |  |  |  | 29 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |  |
Total ending allowance balance |  |  | 29 |  | 29 |  | 29
Loans [Abstract] |  |  |  |  |  |  |
Total recorded investment in loans |  |  |  |  |  | 0 | 792
Commercial and agricultural: |  |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |  |
Beginning balance | 7,003 | 1,650 | 6,976 | 1,589 | 1,589 |  |
Charge-offs | (3,624) | (2) | (3,644) | (7) |  |  |
Recoveries | 11 | 36 | 21 | 61 |  |  |
Net recoveries (charge-offs) | (3,613) | 34 | (3,623) | 54 |  |  |
Provision | 1,579 | 199 | 1,616 | 240 |  |  |
Ending balance | 4,969 | 1,883 | 4,969 | 1,883 | 6,976 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  | 1,285 | 5,135
Collectively evaluated for impairment |  |  |  |  |  | 3,684 | 1,841
Total ending allowance balance | 7,003 | 1,650 | 6,976 | 1,589 | 1,589 | 4,969 | 6,976
Loans [Abstract] |  |  |  |  |  |  |
Loans individually evaluated for impairment |  |  |  |  |  | 2,017 | 6,133
Loans collectively evaluated for impairment |  |  |  |  |  | 192,040 | 193,443
Total recorded investment in loans |  |  |  |  |  | 194,057 | 199,576
Commercial and agricultural: | Loans acquired with deteriorated credit quality |  |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |  |
Beginning balance |  |  | 0 |  |  |  |
Ending balance |  |  |  |  | 0 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |  |
Total ending allowance balance |  |  | 0 |  | 0 |  | 0
Loans [Abstract] |  |  |  |  |  |  |
Total recorded investment in loans |  |  |  |  |  |  | 0
Commercial Mortgages |  |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |  |
Beginning balance | 8,640 | 7,749 | 8,514 | 7,270 | 7,270 |  |
Charge-offs | (145) | 0 | (145) | 0 |  |  |
Recoveries | 1 | 2 | 2 | 3 |  |  |
Net recoveries (charge-offs) | (144) | 2 | (143) | 3 |  |  |
Provision | 244 | 27 | 369 | 505 |  |  |
Ending balance | 8,740 | 7,778 | 8,740 | 7,778 | 8,514 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  | 453 | 802
Collectively evaluated for impairment |  |  |  |  |  | 8,287 | 7,683
Total ending allowance balance | 8,640 | 7,749 | 8,514 | 7,270 | 7,270 | 8,740 | 8,514
Loans [Abstract] |  |  |  |  |  |  |
Loans individually evaluated for impairment |  |  |  |  |  | 6,847 | 7,302
Loans collectively evaluated for impairment |  |  |  |  |  | 661,711 | 638,080
Total recorded investment in loans |  |  |  |  |  | 668,558 | 646,174
Commercial Mortgages | Loans acquired with deteriorated credit quality |  |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |  |
Beginning balance |  |  | 29 |  |  |  |
Ending balance |  |  |  |  | 29 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |  |
Total ending allowance balance |  |  | 29 |  | 29 |  | 29
Loans [Abstract] |  |  |  |  |  |  |
Total recorded investment in loans |  |  |  |  |  |  | 792
Residential mortgages |  |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |  |
Beginning balance | 1,407 | 1,512 | 1,316 | 1,523 | 1,523 |  |
Charge-offs | (71) | (48) | (165) | (60) |  |  |
Recoveries | 0 | 13 | 5 | 30 |  |  |
Net recoveries (charge-offs) | (71) | (35) | (160) | (30) |  |  |
Provision | 109 | 40 | 289 | 24 |  |  |
Ending balance | 1,445 | 1,517 | 1,445 | 1,517 | 1,316 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  | 0 | 0
Collectively evaluated for impairment |  |  |  |  |  | 1,445 | 1,316
Total ending allowance balance | 1,407 | 1,512 | 1,316 | 1,523 | 1,523 | 1,445 | 1,316
Loans [Abstract] |  |  |  |  |  |  |
Loans individually evaluated for impairment |  |  |  |  |  | 417 | 427
Loans collectively evaluated for impairment |  |  |  |  |  | 193,514 | 194,510
Total recorded investment in loans |  |  |  |  |  | 193,931 | 194,937
Residential mortgages | Loans acquired with deteriorated credit quality |  |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |  |
Beginning balance |  |  | 0 |  |  |  |
Ending balance |  |  |  |  | 0 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |  |
Total ending allowance balance |  |  | 0 |  | 0 |  | 0
Loans [Abstract] |  |  |  |  |  |  |
Total recorded investment in loans |  |  |  |  |  | 0 | 0
Consumer loans: |  |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |  |
Beginning balance | 4,340 | 4,049 | 4,355 | 3,871 | 3,871 |  |
Charge-offs | (463) | (397) | (921) | (825) |  |  |
Recoveries | 184 | 119 | 260 | 188 |  |  |
Net recoveries (charge-offs) | (279) | (278) | (661) | (637) |  |  |
Provision | 430 | 155 | 797 | 692 |  |  |
Ending balance | 4,491 | 3,926 | 4,491 | 3,926 | 4,355 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |  |
Individually evaluated for impairment |  |  |  |  |  | 0 | 0
Collectively evaluated for impairment |  |  |  |  |  | 4,491 | 4,355
Total ending allowance balance | $ 4,340 | $ 4,049 | 4,355 | $ 3,871 | 3,871 | 4,491 | 4,355
Loans [Abstract] |  |  |  |  |  |  |
Loans individually evaluated for impairment |  |  |  |  |  | 61 | 64
Loans collectively evaluated for impairment |  |  |  |  |  | 281,503 | 274,831
Total recorded investment in loans |  |  |  |  |  | $ 281,564 | 274,895
Consumer loans: | Loans acquired with deteriorated credit quality |  |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |  |
Beginning balance |  |  | 0 |  |  |  |
Ending balance |  |  |  |  | 0 |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |  |
Total ending allowance balance |  |  | $ 0 |  | $ 0 |  | 0
Loans [Abstract] |  |  |  |  |  |  |
Total recorded investment in loans |  |  |  |  |  |  | $ 0

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