LOANS AND ALLOWANCE FOR CREDIT LOSSES - Troubled Debt Restructurings (TDRs) (Details) $ in Thousands	3 Months Ended
Mar. 31, 2022 USD ($) loan	Mar. 31, 2021 USD ($) loan	Dec. 31, 2021 USD ($) loan
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	228		232
TDRs, amount	$ 8,134		$ 8,239
Loans modified in TDR during the year, number \| loan	8	10
Loans modified in TDR during the year, amount	$ 230	$ 183
Minimum
Financing Receivable, Modifications [Line Items]
Threshold balance of loan individually evaluated for impairment	500
Maximum
Financing Receivable, Modifications [Line Items]
Threshold balance of TDR loans collectively included in general loan loss allocation and qualitative review	$ 500
Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	79		81
TDRs, amount	$ 3,883		$ 3,940
Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	149		151
TDRs, amount	$ 4,251		$ 4,299
Commercial Portfolio Segment \| Business Lending
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	14		14
TDRs, amount	$ 1,809		$ 1,822
Loans modified in TDR during the year, number \| loan	0	0
Loans modified in TDR during the year, amount	$ 0	$ 0
Commercial Portfolio Segment \| Business Lending \| Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	10		10
TDRs, amount	$ 1,002		$ 1,011
Commercial Portfolio Segment \| Business Lending \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	4		4
TDRs, amount	$ 807		$ 811
Residential Portfolio Segment \| Consumer Mortgage
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	107		108
TDRs, amount	$ 5,122		$ 5,114
Loans modified in TDR during the year, number \| loan	4	3
Loans modified in TDR during the year, amount	$ 195	$ 110
Residential Portfolio Segment \| Consumer Mortgage \| Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	59		61
TDRs, amount	$ 2,654		$ 2,694
Residential Portfolio Segment \| Consumer Mortgage \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	48		47
TDRs, amount	$ 2,468		$ 2,420
Consumer Portfolio Segment \| Consumer Indirect
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	69		72
TDRs, amount	$ 746		$ 829
Loans modified in TDR during the year, number \| loan	4	6
Loans modified in TDR during the year, amount	$ 35	$ 66
Consumer Portfolio Segment \| Consumer Indirect \| Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	0		0
TDRs, amount	$ 0		$ 0
Consumer Portfolio Segment \| Consumer Indirect \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	69		72
TDRs, amount	$ 746		$ 829
Consumer Portfolio Segment \| Consumer Direct
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	16		16
TDRs, amount	$ 5		$ 7
Loans modified in TDR during the year, number \| loan	0	1
Loans modified in TDR during the year, amount	$ 0	$ 7
Consumer Portfolio Segment \| Consumer Direct \| Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	0		0
TDRs, amount	$ 0		$ 0
Consumer Portfolio Segment \| Consumer Direct \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	16		16
TDRs, amount	$ 5		$ 7
Consumer Portfolio Segment \| Home Equity
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	22		22
TDRs, amount	$ 452		$ 467
Loans modified in TDR during the year, number \| loan	0	0
Loans modified in TDR during the year, amount	$ 0	$ 0
Consumer Portfolio Segment \| Home Equity \| Nonaccrual [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	10		10
TDRs, amount	$ 227		$ 235
Consumer Portfolio Segment \| Home Equity \| Accruing [Member]
Financing Receivable, Modifications [Line Items]
TDRs, number \| loan	12		12
TDRs, amount	$ 225		$ 232

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Threshold balance of financing receivables classified as a troubled debt restructuring that are collectively evaluated for impairment.

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Amount of financing receivable modified as troubled debt restructuring.

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