LOANS AND ALLOWANCE FOR LOAN LOSSES - Receivables Past Due (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Non-accrual	$ 17,279	$ 18,008
Loans Past Due 90 Days or More and Still Accruing	3	7
Aging of the recorded investment in loans past due [Abstract]
Past Due	10,567	14,370
Loans Not Past Due	1,492,179	1,298,533
Total recorded investment in loans	1,502,746	1,312,903
30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	6,113	4,672
60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	1,082	1,668
90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	3,372	8,029
Commercial and agricultural
Aging of the recorded investment in loans past due [Abstract]
Total recorded investment in loans	396,698	230,922
Commercial Mortgages
Aging of the recorded investment in loans past due [Abstract]
Total recorded investment in loans	672,540	650,570
Commercial Mortgages | Construction
Financing Receivable, Past Due [Line Items]
Non-accrual	70	80
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Loans Not Past Due	47,329	44,082
Total recorded investment in loans	47,329	44,082
Commercial Mortgages | Construction | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Commercial Mortgages | Construction | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Commercial Mortgages | Construction | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Commercial Mortgages | Commercial mortgages
Financing Receivable, Past Due [Line Items]
Non-accrual	6,416	8,407
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	3,274	2,883
Loans Not Past Due	621,937	603,605
Total recorded investment in loans	625,211	606,488
Commercial Mortgages | Commercial mortgages | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	1,046	441
Commercial Mortgages | Commercial mortgages | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	347	277
Commercial Mortgages | Commercial mortgages | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	1,881	2,165
Residential mortgages
Financing Receivable, Past Due [Line Items]
Non-accrual	2,537	2,155
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	1,687	2,775
Loans Not Past Due	207,006	186,099
Total recorded investment in loans	208,693	188,874
Residential mortgages | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	590	1,016
Residential mortgages | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	364	803
Residential mortgages | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	733	956
Consumer Loans
Aging of the recorded investment in loans past due [Abstract]
Total recorded investment in loans	224,815	242,537
Consumer Loans | Home equity lines and loans
Financing Receivable, Past Due [Line Items]
Non-accrual	1,061	641
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	329	653
Loans Not Past Due	85,855	91,412
Total recorded investment in loans	86,184	92,065
Consumer Loans | Home equity lines and loans | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	180	353
Consumer Loans | Home equity lines and loans | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	53	151
Consumer Loans | Home equity lines and loans | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	96	149
Consumer Loans | Indirect consumer loans
Financing Receivable, Past Due [Line Items]
Non-accrual	755	571
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	987	2,278
Loans Not Past Due	124,331	133,088
Total recorded investment in loans	125,318	135,366
Consumer Loans | Indirect consumer loans | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	499	1,546
Consumer Loans | Indirect consumer loans | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	102	377
Consumer Loans | Indirect consumer loans | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	386	355
Consumer Loans | Direct consumer loans
Financing Receivable, Past Due [Line Items]
Non-accrual	1	7
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	3	49
Loans Not Past Due	13,310	15,057
Total recorded investment in loans	13,313	15,106
Consumer Loans | Direct consumer loans | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	2	32
Consumer Loans | Direct consumer loans | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	1	11
Consumer Loans | Direct consumer loans | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	6
Commercial and industrial | Commercial and agricultural
Financing Receivable, Past Due [Line Items]
Non-accrual	6,439	6,147
Loans Past Due 90 Days or More and Still Accruing	3	7
Aging of the recorded investment in loans past due [Abstract]
Past Due	4,287	5,732
Loans Not Past Due	391,993	224,916
Total recorded investment in loans	396,280	230,648
Commercial and industrial | Commercial and agricultural | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	3,796	1,285
Commercial and industrial | Commercial and agricultural | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	215	49
Commercial and industrial | Commercial and agricultural | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	276	4,398
Agricultural | Commercial and agricultural
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Loans Not Past Due	418	274
Total recorded investment in loans	418	274
Agricultural | Commercial and agricultural | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Agricultural | Commercial and agricultural | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Agricultural | Commercial and agricultural | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	$ 0	$ 0