NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)	12 Months Ended
Dec. 31, 2021 USD ($) segment	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Number of reportable segments \| segment	1
Contractual performance period of nonaccrual loans to be restored to accrual status	6 months
Purchased loans past due as deterioration indicator	90 days
Minimum period past due to charge off loans	120 days
Number of distinct segments in loan portfolio \| segment	3
Credit losses related to unfunded loan commitments	$ 13,537,000	$ 11,385,000	$ 9,836,000
Threshold amount of estimate loss for evaluating individual loans for impairment	100,000
Accrued interest related to unrecognized tax benefits	0
Fair value of trust assets under management	$ 1,232,919,000	1,103,228,000
Trust revenue is earned and collected monthly	84.00%
Commercial
Credit losses related to unfunded loan commitments	$ 8,293,000	6,308,000	4,788,000
Commercial \| Maximum
Threshold amount of loan balance for evaluating individual impairment loss	200,000
Residential mortgage
Credit losses related to unfunded loan commitments	4,338,000	4,253,000	4,182,000
Residential mortgage \| Maximum
Threshold amount of loan balance for evaluating individual impairment loss	400,000
Consumer
Credit losses related to unfunded loan commitments	235,000	239,000	$ 281,000
Consumer \| Maximum
Threshold amount of loan balance for evaluating individual impairment loss	400,000
Unfunded Loan Commitment
Credit losses related to unfunded loan commitments	$ 0	$ 0

The fair value of trust assets under management.

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- Definition

The amount of estimated loss on a financing receivable with relationships less than $200,000 in the aggregate which will trigger that financing receivable to be individually evaluated for impairment.

+ References

No definition available.

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Threshold for determining if a financing receivable with an estimated loss of $100,000 or more, will be individually evaluated for impairment.

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- Definition

Minimum loan period past due on a contractual basis to be generally charged off, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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The number of distinct loan segments in loan portfolio.

+ References

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Period of contractual performance of nonaccrual loans restored to accrual status, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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The minimum period of past due of purchased loans considered as indicator of deterioration, 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

The percent of trust revenue earned and collected monthly.

+ References

No definition available.

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- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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- Definition

Amount of interest expense accrued for an underpayment of income taxes.

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