LOANS AND ALLOWANCE FOR CREDIT LOSSES - Receivables Past Due (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Past Due [Line Items]
Financing receivable	$ 2,003,610	$ 1,972,664
Nonaccrual with No Allowance for Credit Losses	6,217	8,529
Nonaccrual	7,835	10,411
Loans Past Due 90 Days or More and Still Accruing	8	10
Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	12,305	14,360
Total Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	245
30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	4,415	9,562
30 - 59 Days Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	0
60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	3,569	943
60 - 89 Days Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	0
90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	4,321	3,855
90 Days or More Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	675
Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,991,305	1,958,304
Loans Not Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	920
Construction
Financing Receivable, Past Due [Line Items]
Financing receivable	141,604	138,887
Commercial mortgages, other
Financing Receivable, Past Due [Line Items]
Financing receivable	1,004,198	984,038
Home equity lines and loans
Financing Receivable, Past Due [Line Items]
Financing receivable	87,608	87,056
Indirect consumer loans
Financing Receivable, Past Due [Line Items]
Financing receivable	204,081	210,423
Direct consumer loans
Financing Receivable, Past Due [Line Items]
Financing receivable	9,238	9,872
Commercial Mortgages
Financing Receivable, Past Due [Line Items]
Financing receivable	1,145,802	1,122,925
Commercial Mortgages | Construction
Financing Receivable, Past Due [Line Items]
Financing receivable	141,604	138,887
Nonaccrual with No Allowance for Credit Losses	2,207	2,209
Nonaccrual	2,207	2,209
Loans Past Due 90 Days or More and Still Accruing	0	0
Commercial Mortgages | Construction | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	2,207	4,371
Commercial Mortgages | Construction | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	0	2,164
Commercial Mortgages | Construction | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	0	0
Commercial Mortgages | Construction | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	2,207	2,207
Commercial Mortgages | Construction | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	139,397	134,516
Commercial Mortgages | Commercial mortgages, other
Financing Receivable, Past Due [Line Items]
Financing receivable	1,004,198	984,038
Nonaccrual with No Allowance for Credit Losses	1,734	3,732
Nonaccrual	1,758	3,760
Loans Past Due 90 Days or More and Still Accruing	0	0
Commercial Mortgages | Commercial mortgages, other | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	3,425	1,386
Commercial Mortgages | Commercial mortgages, other | Total Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable		277
Commercial Mortgages | Commercial mortgages, other | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,012	1,022
Commercial Mortgages | Commercial mortgages, other | 30 - 59 Days Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable		0
Commercial Mortgages | Commercial mortgages, other | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	2,238	103
Commercial Mortgages | Commercial mortgages, other | 60 - 89 Days Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable		0
Commercial Mortgages | Commercial mortgages, other | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	175	261
Commercial Mortgages | Commercial mortgages, other | 90 Days or More Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable		0
Commercial Mortgages | Commercial mortgages, other | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,000,773	982,652
Commercial Mortgages | Commercial mortgages, other | Loans Not Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable		277
Residential Mortgages
Financing Receivable, Past Due [Line Items]
Financing receivable	277,246	277,992
Nonaccrual with No Allowance for Credit Losses	1,118	1,315
Nonaccrual	1,118	1,315
Loans Past Due 90 Days or More and Still Accruing	0	0
Residential Mortgages | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	2,712	3,030
Residential Mortgages | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,529	2,244
Residential Mortgages | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	594	201
Residential Mortgages | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	589	585
Residential Mortgages | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	274,534	274,962
Consumer Loans
Financing Receivable, Past Due [Line Items]
Financing receivable	300,927	307,351
Consumer Loans | Home equity lines and loans
Financing Receivable, Past Due [Line Items]
Financing receivable	87,608	87,056
Nonaccrual with No Allowance for Credit Losses	496	508
Nonaccrual	496	508
Loans Past Due 90 Days or More and Still Accruing	0	0
Consumer Loans | Home equity lines and loans | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	994	914
Consumer Loans | Home equity lines and loans | Total Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	116
Consumer Loans | Home equity lines and loans | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	612	461
Consumer Loans | Home equity lines and loans | 30 - 59 Days Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	0
Consumer Loans | Home equity lines and loans | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	100	87
Consumer Loans | Home equity lines and loans | 60 - 89 Days Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	0
Consumer Loans | Home equity lines and loans | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	282	366
Consumer Loans | Home equity lines and loans | 90 Days or More Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	0
Consumer Loans | Home equity lines and loans | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	86,614	86,142
Consumer Loans | Home equity lines and loans | Loans Not Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	116
Consumer Loans | Indirect consumer loans
Financing Receivable, Past Due [Line Items]
Financing receivable	204,081	210,423
Nonaccrual with No Allowance for Credit Losses	631	687
Nonaccrual	631	687
Loans Past Due 90 Days or More and Still Accruing	0	0
Consumer Loans | Indirect consumer loans | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,821	3,400
Consumer Loans | Indirect consumer loans | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,063	2,473
Consumer Loans | Indirect consumer loans | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	379	501
Consumer Loans | Indirect consumer loans | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	379	426
Consumer Loans | Indirect consumer loans | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	202,260	207,023
Consumer Loans | Direct consumer loans
Financing Receivable, Past Due [Line Items]
Financing receivable	9,238	9,872
Nonaccrual with No Allowance for Credit Losses	8	2
Nonaccrual	8	2
Loans Past Due 90 Days or More and Still Accruing	0	0
Consumer Loans | Direct consumer loans | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	44	22
Consumer Loans | Direct consumer loans | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	18	2
Consumer Loans | Direct consumer loans | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	20	20
Consumer Loans | Direct consumer loans | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	6	0
Consumer Loans | Direct consumer loans | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	9,194	9,850
Commercial and Agricultural Sector | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Financing receivable	279,414	264,140
Nonaccrual with No Allowance for Credit Losses	23	76
Nonaccrual	1,615	1,904
Loans Past Due 90 Days or More and Still Accruing	8	10
Commercial and Agricultural Sector | Commercial and industrial | Total Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	1,102	1,237
Commercial and Agricultural Sector | Commercial and industrial | Total Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	129
Commercial and Agricultural Sector | Commercial and industrial | 30 - 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	181	1,196
Commercial and Agricultural Sector | Commercial and industrial | 30 - 59 Days Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	0
Commercial and Agricultural Sector | Commercial and industrial | 60 - 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	238	31
Commercial and Agricultural Sector | Commercial and industrial | 60 - 89 Days Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	0
Commercial and Agricultural Sector | Commercial and industrial | 90 Days or More Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	683	10
Commercial and Agricultural Sector | Commercial and industrial | 90 Days or More Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	675
Commercial and Agricultural Sector | Commercial and industrial | Loans Not Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable	278,312	262,903
Commercial and Agricultural Sector | Commercial and industrial | Loans Not Past Due | Restructured Debt
Financing Receivable, Past Due [Line Items]
Financing receivable	804
Commercial and Agricultural Sector | Agricultural
Financing Receivable, Past Due [Line Items]
Financing receivable	221	256
Nonaccrual with No Allowance for Credit Losses	0	0
Nonaccrual	2	26
Loans Past Due 90 Days or More and Still Accruing	0	0
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	$ 221	$ 256