LOANS AND ALLOWANCE FOR CREDIT LOSSES - Credit Quality Indicator (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	$ 45,642		$ 307,790
2023	310,315		553,730
2022	549,478		302,467
2021	297,902		218,500
2020	212,684		114,216
Prior	440,662		343,382
Revolving Loans Amortized Cost	142,772		128,225
Revolving Loans Converted to Term	4,155		4,354
Total loans, net of deferred loan fees and costs	2,003,610		1,972,664
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2024	0		188
2023	104		422
2022	127		223
2021	29		127
2020	24		30
Prior	81		381
Revolving Loans Amortized Cost	2		12
Revolving Loans Converted to Term	0		0
Total	367	$ 383	1,383
Construction
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	1,076		46,951
2023	48,500		68,483
2022	77,995		19,066
2021	9,686		0
2020	0		2,235
Prior	3,865		1,671
Revolving Loans Amortized Cost	482		481
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	141,604		138,887
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	0		0
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total	0		0
Construction | Pass
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	1,076		46,951
2023	48,500		68,483
2022	77,995		19,066
2021	9,686		0
2020	0		28
Prior	1,658		1,669
Revolving Loans Amortized Cost	482		481
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	139,397		136,678
Construction | Special mention
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	0		0
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	0		0
Construction | Substandard
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		2,207
Prior	2,207		2
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	2,207		2,209
Construction | Doubtful
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	0		0
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	0		0
Commercial mortgages, other
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	13,784		111,136
2023	119,647		264,403
2022	261,652		170,392
2021	179,521		116,829
2020	115,009		57,782
Prior	306,618		257,435
Revolving Loans Amortized Cost	7,225		5,294
Revolving Loans Converted to Term	742		767
Total loans, net of deferred loan fees and costs	1,004,198		984,038
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	0		0
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total	0		0
Commercial mortgages, other | Pass
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	13,784		110,864
2023	117,235		260,763
2022	258,049		161,858
2021	171,090		113,198
2020	111,407		57,782
Prior	296,080		244,211
Revolving Loans Amortized Cost	5,127		5,197
Revolving Loans Converted to Term	742		767
Total loans, net of deferred loan fees and costs	973,514		954,640
Commercial mortgages, other | Special mention
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	0		2,533
2022	2,522		8,189
2021	8,092		2,609
2020	2,590		0
Prior	8,082		8,642
Revolving Loans Amortized Cost	2,001		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	23,287		21,973
Commercial mortgages, other | Substandard
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		272
2023	2,412		1,107
2022	1,081		345
2021	339		1,022
2020	1,012		0
Prior	2,432		4,555
Revolving Loans Amortized Cost	97		97
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	7,373		7,398
Commercial mortgages, other | Doubtful
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	24		27
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	24		27
Home equity lines and loans
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	3,298		13,552
2023	12,904		16,461
2022	16,038		5,821
2021	5,577		3,134
2020	3,009		2,867
Prior	12,785		10,693
Revolving Loans Amortized Cost	32,859		33,300
Revolving Loans Converted to Term	1,138		1,228
Total loans, net of deferred loan fees and costs	87,608		87,056
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	11		0
Revolving Loans Amortized Cost	0		6
Revolving Loans Converted to Term	0		0
Total	11		6
Home equity lines and loans | Not rated
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	3,298		13,552
2023	12,904		16,384
2022	15,846		5,821
2021	5,577		3,134
2020	3,009		2,867
Prior	12,494		10,400
Revolving Loans Amortized Cost	32,773		33,275
Revolving Loans Converted to Term	1,095		1,115
Total loans, net of deferred loan fees and costs	86,996		86,548
Home equity lines and loans | Special mention
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0
2023	0
2022	116
2021	0
2020	0
Prior	0
Revolving Loans Amortized Cost	0
Revolving Loans Converted to Term	0
Total loans, net of deferred loan fees and costs	116
Home equity lines and loans | Substandard
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	0		77
2022	76		0
2021	0		0
2020	0		0
Prior	291		293
Revolving Loans Amortized Cost	86		25
Revolving Loans Converted to Term	43		113
Total loans, net of deferred loan fees and costs	496		508
Indirect consumer
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	11,861		72,383
2023	67,540		98,254
2022	90,621		23,150
2021	20,552		9,240
2020	7,701		3,906
Prior	5,806		3,490
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	204,081		210,423
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2024	0		184
2023	104		375
2022	127		215
2021	29		121
2020	24		21
Prior	54		55
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total	338		971
Indirect consumer | Not rated
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	11,861		72,264
2023	67,401		98,008
2022	90,413		23,015
2021	20,411		9,192
2020	7,652		3,870
Prior	5,712		3,387
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	203,450		209,736
Indirect consumer | Substandard
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		119
2023	139		246
2022	208		135
2021	141		48
2020	49		36
Prior	94		103
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	631		687
Direct consumer
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	700		3,005
2023	2,622		2,745
2022	2,391		785
2021	612		258
2020	176		53
Prior	332		324
Revolving Loans Amortized Cost	2,402		2,697
Revolving Loans Converted to Term	3		5
Total loans, net of deferred loan fees and costs	9,238		9,872
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2024	0		4
2023	0		15
2022	0		8
2021	0		6
2020	0		0
Prior	0		54
Revolving Loans Amortized Cost	2		6
Revolving Loans Converted to Term	0		0
Total	2		93
Direct consumer | Not rated
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	700		3,005
2023	2,622		2,745
2022	2,391		785
2021	607		256
2020	174		53
Prior	332		324
Revolving Loans Amortized Cost	2,401		2,697
Revolving Loans Converted to Term	3		5
Total loans, net of deferred loan fees and costs	9,230		9,870
Direct consumer | Substandard
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	0		0
2022	0		0
2021	5		2
2020	2		0
Prior	0		0
Revolving Loans Amortized Cost	1		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	8		2
Commercial & industrial
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	10,909		42,110
2023	39,100		45,196
2022	43,488		22,733
2021	22,158		17,670
2020	16,492		31,256
Prior	45,253		16,459
Revolving Loans Amortized Cost	99,742		86,388
Revolving Loans Converted to Term	2,272		2,328
Total loans, net of deferred loan fees and costs	279,414		264,140
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		9
Prior	0		272
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total	0		281
Commercial & industrial | Pass
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	10,885		41,925
2023	39,011		40,564
2022	34,108		21,742
2021	21,370		13,541
2020	12,349		31,233
Prior	39,698		10,523
Revolving Loans Amortized Cost	92,497		77,176
Revolving Loans Converted to Term	1,643		1,662
Total loans, net of deferred loan fees and costs	251,561		238,366
Commercial & industrial | Special mention
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		185
2023	0		4,608
2022	9,159		0
2021	0		4,020
2020	4,060		0
Prior	4,586		4,690
Revolving Loans Amortized Cost	7,223		9,137
Revolving Loans Converted to Term	453		482
Total loans, net of deferred loan fees and costs	25,481		23,122
Commercial & industrial | Substandard
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	89		24
2022	221		991
2021	788		109
2020	83		23
Prior	205		456
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	176		161
Total loans, net of deferred loan fees and costs	1,562		1,764
Commercial & industrial | Doubtful
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	24		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	764		790
Revolving Loans Amortized Cost	22		75
Revolving Loans Converted to Term	0		23
Total loans, net of deferred loan fees and costs	810		888
Agricultural
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	2		15
2022	14		150
2021	143		0
2020	0		0
Prior	0		0
Revolving Loans Amortized Cost	62		65
Revolving Loans Converted to Term	0		26
Total loans, net of deferred loan fees and costs	221		256
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	0		0
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total	0		0
Agricultural | Pass
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	0		15
2022	14		150
2021	143		0
2020	0		0
Prior	0		0
Revolving Loans Amortized Cost	62		65
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	219		230
Agricultural | Special mention
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	0		0
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	0		0
Agricultural | Substandard
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	2		0
2022	0		0
2021	0		0
2020	0		0
Prior	0		0
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		26
Total loans, net of deferred loan fees and costs	2		26
Agricultural | Doubtful
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	0		0
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	0		0
Commercial and Agricultural
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans, net of deferred loan fees and costs	279,635		264,396
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Total	0	190
Commercial and Agricultural | Commercial & industrial
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans, net of deferred loan fees and costs	279,414		264,140
Commercial and Agricultural | Agricultural
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans, net of deferred loan fees and costs	221		256
Commercial Mortgages
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans, net of deferred loan fees and costs	1,145,802		1,122,925
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Total	0	0
Commercial Mortgages | Construction
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans, net of deferred loan fees and costs	141,604		138,887
Commercial Mortgages | Commercial mortgages, other
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans, net of deferred loan fees and costs	1,004,198		984,038
Residential Mortgages
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	4,014		18,653
2023	20,000		58,173
2022	57,279		60,370
2021	59,653		71,369
2020	70,297		16,117
Prior	66,003		53,310
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	277,246		277,992
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2024	0		0
2023	0		32
2022	0		0
2021	0		0
2020	0		0
Prior	16		0
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total	16	0	32
Residential Mortgages | Not rated
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	4,014		18,653
2023	20,000		58,098
2022	57,204		60,024
2021	59,311		71,369
2020	70,050		15,948
Prior	65,549		52,585
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	276,128		276,677
Residential Mortgages | Substandard
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
2024	0		0
2023	0		75
2022	75		346
2021	342		0
2020	247		169
Prior	454		725
Revolving Loans Amortized Cost	0		0
Revolving Loans Converted to Term	0		0
Total loans, net of deferred loan fees and costs	1,118		1,315
Consumer Loans
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans, net of deferred loan fees and costs	300,927		307,351
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Total	351	$ 193
Consumer Loans | Home equity lines and loans
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans, net of deferred loan fees and costs	87,608		87,056
Consumer Loans | Indirect consumer
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans, net of deferred loan fees and costs	204,081		210,423
Consumer Loans | Direct consumer
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, by Origination Year [Abstract]
Total loans, net of deferred loan fees and costs	$ 9,238		$ 9,872