LOANS AND ALLOWANCE FOR CREDIT LOSSES - Receivables Past Due (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Non-accrual with no allowance for credit losses	$ 5,787
Non-accrual	6,826	$ 8,178
Loans Past Due 90 Days or More and Still Accruing	0	1
Financing receivable	1,930,688	1,829,448
Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	7,919	6,603
30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	6,164	4,084
60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	444	1,045
90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,311	1,474
Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,922,769	1,822,845
Construction
Financing Receivable, Past Due [Line Items]
Financing receivable	140,480
Commercial mortgages, other
Financing Receivable, Past Due [Line Items]
Financing receivable	946,053
Home equity lines and loans
Financing Receivable, Past Due [Line Items]
Financing receivable	87,078
Indirect consumer loans
Financing Receivable, Past Due [Line Items]
Financing receivable	211,046
Direct consumer loans
Financing Receivable, Past Due [Line Items]
Financing receivable	10,186
Commercial mortgages, other
Financing Receivable, Past Due [Line Items]
Financing receivable	1,086,533	996,913
Commercial mortgages, other | Construction
Financing Receivable, Past Due [Line Items]
Non-accrual	0	5
Loans Past Due 90 Days or More and Still Accruing	0	0
Financing receivable	140,480	108,243
Commercial mortgages, other | Construction | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	2,206	0
Commercial mortgages, other | Construction | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	2,206	0
Commercial mortgages, other | Construction | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
Commercial mortgages, other | Construction | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
Commercial mortgages, other | Construction | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	138,274	108,243
Commercial mortgages, other | Commercial mortgages, other
Financing Receivable, Past Due [Line Items]
Non-accrual	3,824	3,928
Loans Past Due 90 Days or More and Still Accruing	0	0
Financing receivable	946,053	888,670
Commercial mortgages, other | Commercial mortgages, other | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,338	1,544
Commercial mortgages, other | Commercial mortgages, other | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,073	1,058
Commercial mortgages, other | Commercial mortgages, other | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	4	0
Commercial mortgages, other | Commercial mortgages, other | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	261	486
Commercial mortgages, other | Commercial mortgages, other | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	944,715	887,126
Residential Mortgages
Financing Receivable, Past Due [Line Items]
Non-accrual	776	986
Loans Past Due 90 Days or More and Still Accruing	0	0
Financing receivable	281,361	285,672
Residential Mortgages | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,535	2,363
Residential Mortgages | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,217	1,360
Residential Mortgages | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	63	709
Residential Mortgages | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	255	294
Residential Mortgages | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	279,826	283,309
Consumer Loans
Financing Receivable, Past Due [Line Items]
Financing receivable	308,310	294,570
Consumer Loans | Home equity lines and loans
Financing Receivable, Past Due [Line Items]
Non-accrual	565	760
Loans Past Due 90 Days or More and Still Accruing	0	0
Financing receivable	87,078	81,401
Consumer Loans | Home equity lines and loans | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	621	756
Consumer Loans | Home equity lines and loans | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	151	193
Consumer Loans | Home equity lines and loans | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	49	121
Consumer Loans | Home equity lines and loans | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	421	442
Consumer Loans | Home equity lines and loans | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	86,457	80,645
Consumer Loans | Indirect consumer loans
Financing Receivable, Past Due [Line Items]
Non-accrual	621	540
Loans Past Due 90 Days or More and Still Accruing	0	0
Financing receivable	211,046	202,124
Consumer Loans | Indirect consumer loans | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,993	1,840
Consumer Loans | Indirect consumer loans | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,313	1,397
Consumer Loans | Indirect consumer loans | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	312	193
Consumer Loans | Indirect consumer loans | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	368	250
Consumer Loans | Indirect consumer loans | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	209,053	200,284
Consumer Loans | Direct consumer loans
Financing Receivable, Past Due [Line Items]
Non-accrual with no allowance for credit losses	8
Non-accrual	8	13
Loans Past Due 90 Days or More and Still Accruing	0	0
Financing receivable	10,186	11,045
Consumer Loans | Direct consumer loans | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	15	22
Consumer Loans | Direct consumer loans | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	9	2
Consumer Loans | Direct consumer loans | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	0	19
Consumer Loans | Direct consumer loans | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	6	1
Consumer Loans | Direct consumer loans | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	10,171	11,023
Commercial and Agricultural Sector | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Non-accrual	1,004	1,946
Loans Past Due 90 Days or More and Still Accruing	0	1
Financing receivable	254,215	252,044
Commercial and Agricultural Sector | Commercial and industrial | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	211	78
Commercial and Agricultural Sector | Commercial and industrial | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	195	74
Commercial and Agricultural Sector | Commercial and industrial | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	16	3
Commercial and Agricultural Sector | Commercial and industrial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	0	1
Commercial and Agricultural Sector | Commercial and industrial | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	254,004	251,966
Commercial and Agricultural Sector | Agricultural
Financing Receivable, Past Due [Line Items]
Non-accrual with no allowance for credit losses	0
Non-accrual	28	0
Loans Past Due 90 Days or More and Still Accruing	0	0
Financing receivable	269	249
Commercial and Agricultural Sector | Agricultural | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
Commercial and Agricultural Sector | Agricultural | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
Commercial and Agricultural Sector | Agricultural | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
Commercial and Agricultural Sector | Agricultural | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
Commercial and Agricultural Sector | Agricultural | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	$ 269	$ 249