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LOANS AND ALLOWANCE FOR LOAN LOSSES - Allowances (Details) - USD ($) $ in Thousands | 3 Months Ended |  |  |  |
--- | --- | --- | --- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Mar. 31, 2018 | Dec. 31, 2017 | Jun. 30, 2017 | Jun. 30, 2016
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | $ 21,161 |  |  |  |  |
Charge-offs | (571) | $ (444) |  |  |  |
Recoveries | 91 | 111 |  |  |  |
Net recoveries (charge-offs) | (480) | (333) |  |  |  |
Provision | 709 | 1,040 |  |  |  |
Ending balance | 21,390 | 14,960 |  |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Individually evaluated for impairment |  |  | $ 5,681 | $ 5,937 |  |
Collectively evaluated for impairment |  |  | 15,709 | 15,195 |  |
Total ending allowance balance | 21,161 | 14,960 | 21,390 | 21,161 | $ 21,161 | $ 14,253
Loans [Abstract] |  |  |  |  |  |
Loans individually evaluated for impairment |  |  | 13,640 | 13,926 |  |
Loans collectively evaluated for impairment |  |  | 1,309,889 | 1,300,864 |  |
Total ending loans balance |  |  | 1,323,529 | 1,315,582 |  |
Loans acquired with deteriorated credit quality |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | 29 |  |  |  |  |
Ending balance |  |  |  |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Total ending allowance balance | 29 |  |  | 29 |  |
Loans [Abstract] |  |  |  |  |  |
Total ending loans balance |  |  | 0 | 792 |  |
Commercial and agricultural: |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | 6,976 |  |  |  |  |
Charge-offs | (19) | (5) |  |  |  |
Recoveries | 9 | 24 |  |  |  |
Net recoveries (charge-offs) | (10) | 19 |  |  |  |
Provision | 37 | 42 |  |  |  |
Ending balance | 7,003 | 1,650 |  |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Individually evaluated for impairment |  |  | 4,910 | 5,135 |  |
Collectively evaluated for impairment |  |  | 2,093 | 1,841 |  |
Total ending allowance balance | 6,976 | 1,650 | 7,003 | 6,976 | 6,976 | 1,589
Loans [Abstract] |  |  |  |  |  |
Loans individually evaluated for impairment |  |  | 5,795 | 6,133 |  |
Loans collectively evaluated for impairment |  |  | 195,242 | 193,443 |  |
Total ending loans balance |  |  | 201,037 | 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 |  |  |  |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Total ending allowance balance | 0 |  |  | 0 |  |
Loans [Abstract] |  |  |  |  |  |
Total ending loans balance |  |  |  | 0 |  |
Commercial Mortgages |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | 8,514 |  |  |  |  |
Charge-offs | 0 | 0 |  |  |  |
Recoveries | 1 | 1 |  |  |  |
Net recoveries (charge-offs) | 1 | 1 |  |  |  |
Provision | 125 | 478 |  |  |  |
Ending balance | 8,640 | 7,749 |  |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Individually evaluated for impairment |  |  | 771 | 802 |  |
Collectively evaluated for impairment |  |  | 7,869 | 7,683 |  |
Total ending allowance balance | 8,514 | 7,749 | 8,640 | 8,514 | 8,514 | 7,270
Loans [Abstract] |  |  |  |  |  |
Loans individually evaluated for impairment |  |  | 7,359 | 7,302 |  |
Loans collectively evaluated for impairment |  |  | 642,054 | 638,080 |  |
Total ending loans balance |  |  | 649,413 | 646,174 |  |
Commercial Mortgages | Loans acquired with deteriorated credit quality |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | 29 |  |  |  |  |
Ending balance |  |  |  |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Total ending allowance balance | 29 |  |  | 29 |  |
Loans [Abstract] |  |  |  |  |  |
Total ending loans balance |  |  |  | 792 |  |
Residential mortgages |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | 1,316 |  |  |  |  |
Charge-offs | (94) | (12) |  |  |  |
Recoveries | 5 | 17 |  |  |  |
Net recoveries (charge-offs) | (89) | 5 |  |  |  |
Provision | 180 | (16) |  |  |  |
Ending balance | 1,407 | 1,512 |  |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Individually evaluated for impairment |  |  | 0 | 0 |  |
Collectively evaluated for impairment |  |  | 1,407 | 1,316 |  |
Total ending allowance balance | 1,316 | 1,512 | 1,407 | 1,316 | 1,316 | 1,523
Loans [Abstract] |  |  |  |  |  |
Loans individually evaluated for impairment |  |  | 425 | 427 |  |
Loans collectively evaluated for impairment |  |  | 194,671 | 194,510 |  |
Total ending loans balance |  |  | 195,096 | 194,937 |  |
Residential mortgages | Loans acquired with deteriorated credit quality |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | 0 |  |  |  |  |
Ending balance |  |  |  |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Total ending allowance balance | 0 |  |  | 0 |  |
Loans [Abstract] |  |  |  |  |  |
Total ending loans balance |  |  | 0 | 0 |  |
Consumer loans: |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | 4,355 |  |  |  |  |
Charge-offs | (458) | (427) |  |  |  |
Recoveries | 76 | 69 |  |  |  |
Net recoveries (charge-offs) | (382) | (358) |  |  |  |
Provision | 367 | 536 |  |  |  |
Ending balance | 4,340 | 4,049 |  |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Individually evaluated for impairment |  |  | 0 | 0 |  |
Collectively evaluated for impairment |  |  | 4,340 | 4,355 |  |
Total ending allowance balance | 4,355 | $ 4,049 | 4,340 | 4,355 | $ 4,355 | $ 3,871
Loans [Abstract] |  |  |  |  |  |
Loans individually evaluated for impairment |  |  | 61 | 64 |  |
Loans collectively evaluated for impairment |  |  | 277,922 | 274,831 |  |
Total ending loans balance |  |  | $ 277,983 | 274,895 |  |
Consumer loans: | Loans acquired with deteriorated credit quality |  |  |  |  |  |
Allowance for loan losses, by portfolio segment [Roll Forward] |  |  |  |  |  |
Beginning balance | 0 |  |  |  |  |
Ending balance |  |  |  |  |  |
Ending allowance balance attributable to loans [Abstract] |  |  |  |  |  |
Total ending allowance balance | $ 0 |  |  | 0 |  |
Loans [Abstract] |  |  |  |  |  |
Total ending loans balance |  |  |  | $ 0 |  |

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