NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)	12 Months Ended
Dec. 31, 2024 USD ($) item segment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Number of reportable segments \| segment	1
Contractual performance period of nonaccrual loans to be restored to accrual status	6 months
Credit losses related to unfunded loan commitments	$ 20,035,000	$ 19,208,000	$ 16,615,000
Debt security delinquent period to put in nonaccrual status	90 days
Allowance for credit losses related to the available-for-sale portfolio	$ 0	0
Interest receivable	1,964,000	2,018,000
Interest receivable excluded from the estimate of credit losses	$ 6,680,000	$ 7,099,000
Minimum of credit extension of loans for inclusion in individual review for credit losses \| item	1
Repayment period of credit facilities	1 year
Weighted-average remaining life of the entire portfolio	4 years 14 days	4 years 5 months 23 days	4 years 4 months 9 days
Forecast relevant to collectability of cash flows	2 years
Loans Portfolio, Number of Extension For Individual Review \| item	1
Accrued interest related to unrecognized tax benefits	$ 0
Fair value of trust assets under management	$ 1,347,853,000	$ 1,188,082,000
Trust revenue is earned and collected monthly	81.00%
Minimum \| Buildings and improvements
Useful lives	3 years
Minimum \| Furniture and equipment
Useful lives	3 years
Maximum \| Buildings and improvements
Useful lives	40 years
Maximum \| Furniture and equipment
Useful lives	7 years
Residential mortgage
Threshold amount of financing receivables individually evaluated for credit losses	$ 200,000
Consumer
Threshold amount of financing receivables individually evaluated for credit losses	$ 400,000

The fair value of trust assets under management.

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- Definition

Repayment term of credit facilities, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The period debt security becomes delinquent in principal and interest to put in nonaccrual status, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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No definition available.

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Estimate weighted-average remaining life of financing receivable.

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No definition available.

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The forecast period as forward-looking information that is both reasonable and supportable and relevant to the collectability of cash flows of financing receivable, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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No definition available.

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- Definition

The threshold amount of financing receivables for credit losses review that were individually evaluated for impairment.

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No definition available.

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- Definition

The number of extensions of credit to a loan after which the loan gets included in individual review for credit losses.

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No definition available.

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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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- 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 investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
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- Definition

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
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-Publisher FASB
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- Definition

Amount of interest income from financing receivable before allowance for credit loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1402
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- Definition

Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

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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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

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- Definition

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

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