LOANS (Impaired Financing Receivables) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Impaired [Line Items]
Unpaid principal balance		$ 14,789	$ 8,681
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		8,286	8,228
Impaired Financing Receivable, with Related Allowance, Recorded Investment		6,327	266
Impaired Financing Receivable, Recorded Investment		14,613	8,494
Impaired Financing Receivable, Related Allowance		891	266
Average recorded investment		14,659	9,487
Interest income recognized		147	447
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	$ 21,382	18,256	18,417	$ 19,424
Financing Receivable, Allowance for Credit Loss, Writeoff	0	(1,485)
Financing Receivable, Allowance for Credit Losses, Recovery	19	22
Provisions	450	295
Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest			2,496
Commercial real estate
Financing Receivable, Impaired [Line Items]
Unpaid principal balance		12,029	4,994
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		5,641	4,797
Impaired Financing Receivable, with Related Allowance, Recorded Investment		6,290	93
Impaired Financing Receivable, Recorded Investment		11,931	4,890
Impaired Financing Receivable, Related Allowance		854	93
Average recorded investment		11,937	4,866
Interest income recognized		110	254
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	17,313	13,285	13,095	13,744
Financing Receivable, Allowance for Credit Loss, Writeoff	0	(1,247)
Financing Receivable, Allowance for Credit Losses, Recovery	0	1
Provisions	484	787
Commercial real estate \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest			3,734
Residential first mortgages
Financing Receivable, Impaired [Line Items]
Unpaid principal balance		794	879
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		751	866
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	0
Impaired Financing Receivable, Recorded Investment		751	866
Impaired Financing Receivable, Related Allowance		0	0
Average recorded investment		756	874
Interest income recognized		11	32
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	284	1,024	1,002	1,305
Financing Receivable, Allowance for Credit Loss, Writeoff	0	(142)
Financing Receivable, Allowance for Credit Losses, Recovery	0	0
Provisions	(39)	(139)
Residential first mortgages \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest			(679)
Residential rentals
Financing Receivable, Impaired [Line Items]
Unpaid principal balance		741	982
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		736	942
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	0
Impaired Financing Receivable, Recorded Investment		736	942
Impaired Financing Receivable, Related Allowance		0	0
Average recorded investment		744	959
Interest income recognized		10	48
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	1,546	1,361	2,175	1,413
Financing Receivable, Allowance for Credit Loss, Writeoff	0	(46)
Financing Receivable, Allowance for Credit Losses, Recovery	0	0
Provisions	(43)	(6)
Residential rentals \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest			(586)
Home equity and second mortgages
Financing Receivable, Impaired [Line Items]
Unpaid principal balance		666	626
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		651	601
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	0
Impaired Financing Receivable, Recorded Investment		651	601
Impaired Financing Receivable, Related Allowance		0	0
Average recorded investment		657	604
Interest income recognized		4	14
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	178	263	274	261
Financing Receivable, Allowance for Credit Loss, Writeoff	0	0
Financing Receivable, Allowance for Credit Losses, Recovery	0	1
Provisions	(10)	1
Home equity and second mortgages \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest			(86)
Commercial loans
Financing Receivable, Impaired [Line Items]
Unpaid principal balance		0	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		0	0
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	0
Impaired Financing Receivable, Recorded Investment		0	0
Impaired Financing Receivable, Related Allowance		0	0
Average recorded investment		0	0
Interest income recognized		0	0
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	319	1,012	582	1,222
Financing Receivable, Allowance for Credit Loss, Writeoff	0	(50)
Financing Receivable, Allowance for Credit Losses, Recovery	1	5
Provisions	26	(165)
Commercial loans \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest			(290)
Commercial equipment
Financing Receivable, Impaired [Line Items]
Unpaid principal balance		559	1,200
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		507	1,022
Impaired Financing Receivable, with Related Allowance, Recorded Investment		37	173
Impaired Financing Receivable, Recorded Investment		544	1,195
Impaired Financing Receivable, Related Allowance		37	173
Average recorded investment		565	2,184
Interest income recognized		12	99
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	1,532	917	971	1,058
Financing Receivable, Allowance for Credit Loss, Writeoff	0	0
Financing Receivable, Allowance for Credit Losses, Recovery	18	15
Provisions	60	(156)
Commercial equipment \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest			483
Construction and land development
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	137	365	260	$ 401
Financing Receivable, Allowance for Credit Loss, Writeoff	0	0
Financing Receivable, Allowance for Credit Losses, Recovery	0	0
Provisions	$ (41)	$ (36)
Construction and land development \| Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Impaired [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest			$ (82)

Amount excluding accrued interest, of allowance for credit loss on financing receivable.

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Amount of increase in allowance for credit loss on financing receivable from recovery.

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Amount of writeoff of financing receivable, charged against allowance for credit loss.

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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Amount of allowance for credit losses related to recorded investment.

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Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

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Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

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Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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