LOANS AND ALLOWANCE FOR LOAN LOSSES - Receivables Past Due (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	$ 9,952	$ 18,008
Loans Past Due 90 Days or More and Still Accruing	2	7
Past due	10,480	14,370
Loans Not Past Due	1,531,018	1,298,533
Total recorded investment in loans	1,541,498	1,312,903
30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	4,598	4,672
60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	4,357	1,668
90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,525	8,029
Commercial, and Agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total recorded investment in loans	370,252	230,922
Commercial mortgages:
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total recorded investment in loans	719,145	650,570
Residential Mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	1,632	2,155
Loans Past Due 90 Days or More and Still Accruing	0	0
Past due	1,684	2,775
Loans Not Past Due	238,329	186,099
Total recorded investment in loans	240,013	188,874
Residential Mortgages | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	817	1,016
Residential Mortgages | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	406	803
Residential Mortgages | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	461	956
Consumer Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total recorded investment in loans	212,088	242,537
Construction | Commercial mortgages:
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	55	80
Loans Past Due 90 Days or More and Still Accruing	0	0
Past due	0	0
Loans Not Past Due	62,164	44,082
Total recorded investment in loans	62,164	44,082
Construction | Commercial mortgages: | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Construction | Commercial mortgages: | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Construction | Commercial mortgages: | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Commercial mortgages | Commercial mortgages:
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	4,415	8,407
Loans Past Due 90 Days or More and Still Accruing	0	0
Past due	5,442	2,883
Loans Not Past Due	651,539	603,605
Total recorded investment in loans	656,981	606,488
Commercial mortgages | Commercial mortgages: | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,438	440
Commercial mortgages | Commercial mortgages: | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	3,696	277
Commercial mortgages | Commercial mortgages: | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	308	2,165
Home equity lines and loans | Consumer Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	1,159	641
Loans Past Due 90 Days or More and Still Accruing	0	0
Past due	1,036	653
Loans Not Past Due	77,725	91,412
Total recorded investment in loans	78,761	92,065
Home equity lines and loans | Consumer Loans | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	521	353
Home equity lines and loans | Consumer Loans | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	41	151
Home equity lines and loans | Consumer Loans | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	474	149
Indirect Consumer Loans | Consumer Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	519	571
Loans Past Due 90 Days or More and Still Accruing	0	0
Past due	1,718	2,278
Loans Not Past Due	119,135	133,088
Total recorded investment in loans	120,853	135,366
Indirect Consumer Loans | Consumer Loans | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,268	1,546
Indirect Consumer Loans | Consumer Loans | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	198	377
Indirect Consumer Loans | Consumer Loans | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	252	355
Direct consumer loans | Consumer Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	5	7
Loans Past Due 90 Days or More and Still Accruing	0	0
Past due	36	49
Loans Not Past Due	12,438	15,057
Total recorded investment in loans	12,474	15,106
Direct consumer loans | Consumer Loans | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	34	32
Direct consumer loans | Consumer Loans | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	2	11
Direct consumer loans | Consumer Loans | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	6
Commercial and industrial | Commercial, and Agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	2,167	6,147
Loans Past Due 90 Days or More and Still Accruing	2	7
Past due	564	5,732
Loans Not Past Due	369,404	224,916
Total recorded investment in loans	369,968	230,648
Commercial and industrial | Commercial, and Agricultural | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	520	1,285
Commercial and industrial | Commercial, and Agricultural | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	14	49
Commercial and industrial | Commercial, and Agricultural | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	30	4,398
Agricultural | Commercial, and Agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Loans Not Past Due	284	274
Total recorded investment in loans	284	274
Agricultural | Commercial, and Agricultural | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Agricultural | Commercial, and Agricultural | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Agricultural | Commercial, and Agricultural | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	$ 0	$ 0