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LOANS AND ALLOWANCE FOR LOAN LOSSES - Credit Quality Indicator (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	$ 1,520,929	$ 1,541,498
Not Rated
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	455,536	448,787
Pass
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	1,002,904	1,036,759
Special Mention
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	36,502	26,630
Substandard
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	23,670	26,813
Doubtful
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	2,317	2,509
Commercial and agricultural:
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	271,872	370,252
Commercial and agricultural: | Commercial and industrial
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	271,451	369,968
Commercial and agricultural: | Commercial and industrial | Not Rated
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Commercial and agricultural: | Commercial and industrial | Pass
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	264,526	360,500
Commercial and agricultural: | Commercial and industrial | Special Mention
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	2,565	2,999
Commercial and agricultural: | Commercial and industrial | Substandard
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	3,166	5,092
Commercial and agricultural: | Commercial and industrial | Doubtful
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	1,194	1,377
Commercial and agricultural: | Agricultural
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	421	284
Commercial and agricultural: | Agricultural | Not Rated
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Commercial and agricultural: | Agricultural | Pass
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	421	284
Commercial and agricultural: | Agricultural | Special Mention
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Commercial and agricultural: | Agricultural | Substandard
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Commercial and agricultural: | Agricultural | Doubtful
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Commercial mortgages:
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	791,476	719,145
Commercial mortgages: | Construction
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	67,644	62,164
Commercial mortgages: | Construction | Not Rated
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Commercial mortgages: | Construction | Pass
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	67,607	59,885
Commercial mortgages: | Construction | Special Mention
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Commercial mortgages: | Construction | Substandard
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	37	2,279
Commercial mortgages: | Construction | Doubtful
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Commercial mortgages: | Commercial mortgages
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	723,832	656,981
Commercial mortgages: | Commercial mortgages | Not Rated
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Commercial mortgages: | Commercial mortgages | Pass
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	670,350	616,090
Commercial mortgages: | Commercial mortgages | Special Mention
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	33,937	23,631
Commercial mortgages: | Commercial mortgages | Substandard
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	18,422	16,128
Commercial mortgages: | Commercial mortgages | Doubtful
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	1,123	1,132
Residential mortgages
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	254,641	240,013
Residential and consumer finance receivable [Abstract]
Residential and consumer loans receivable	254,641	240,013
Residential mortgages | Performing
Residential and consumer finance receivable [Abstract]
Residential and consumer loans receivable	253,796	238,381
Residential mortgages | Non-Performing
Residential and consumer finance receivable [Abstract]
Residential and consumer loans receivable	845	1,632
Residential mortgages | Not Rated
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	253,796	238,381
Residential mortgages | Pass
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Residential mortgages | Special Mention
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Residential mortgages | Substandard
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	845	1,632
Residential mortgages | Doubtful
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Consumer loans:
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	202,940	212,088
Consumer loans: | Home equity lines and loans
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	72,653	78,761
Residential and consumer finance receivable [Abstract]
Residential and consumer loans receivable	72,653	78,761
Consumer loans: | Home equity lines and loans | Performing
Residential and consumer finance receivable [Abstract]
Residential and consumer loans receivable	71,834	77,602
Consumer loans: | Home equity lines and loans | Non-Performing
Residential and consumer finance receivable [Abstract]
Residential and consumer loans receivable	819	1,159
Consumer loans: | Home equity lines and loans | Not Rated
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	71,834	77,602
Consumer loans: | Home equity lines and loans | Pass
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Consumer loans: | Home equity lines and loans | Special Mention
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Consumer loans: | Home equity lines and loans | Substandard
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	819	1,159
Consumer loans: | Home equity lines and loans | Doubtful
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Consumer loans: | Indirect consumer loans
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	120,045	120,853
Residential and consumer finance receivable [Abstract]
Residential and consumer loans receivable	120,045	120,853
Consumer loans: | Indirect consumer loans | Performing
Residential and consumer finance receivable [Abstract]
Residential and consumer loans receivable	119,678	120,334
Consumer loans: | Indirect consumer loans | Non-Performing
Residential and consumer finance receivable [Abstract]
Residential and consumer loans receivable	367	519
Consumer loans: | Indirect consumer loans | Not Rated
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	119,678	120,334
Consumer loans: | Indirect consumer loans | Pass
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Consumer loans: | Indirect consumer loans | Special Mention
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Consumer loans: | Indirect consumer loans | Substandard
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	367	519
Consumer loans: | Indirect consumer loans | Doubtful
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Consumer loans: | Direct consumer loans
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	10,242	12,474
Consumer loans: | Direct consumer loans | Not Rated
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	10,228	12,470
Consumer loans: | Direct consumer loans | Pass
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Consumer loans: | Direct consumer loans | Special Mention
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Consumer loans: | Direct consumer loans | Substandard
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	14	4
Consumer loans: | Direct consumer loans | Doubtful
Finance receivable by credit quality indicator [Abstract]
Total financing receivables	0	0
Consumer loans: | Other Direct Consumer Loans
Residential and consumer finance receivable [Abstract]
Residential and consumer loans receivable	10,242	12,474
Consumer loans: | Other Direct Consumer Loans | Performing
Residential and consumer finance receivable [Abstract]
Residential and consumer loans receivable	10,228	12,470
Consumer loans: | Other Direct Consumer Loans | Non-Performing
Residential and consumer finance receivable [Abstract]
Residential and consumer loans receivable	$ 14	$ 4

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