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LOANS AND ALLOWANCE FOR CREDIT LOSSES - Loan Portfolio (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	$ 2,028,954		$ 1,972,664
Allowance for credit losses	(21,441)	$ (21,031)	(22,517)	$ (20,252)	$ (20,172)	$ (19,659)
Loans, net	2,007,513		1,950,147
Commercial Mortgages
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	1,174,939		1,122,925
Allowance for credit losses	(10,762)	(10,530)	(12,026)	(11,025)	(10,994)	(11,576)
Commercial Mortgages | Construction
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	138,710		138,887
Allowance for credit losses	0		0
Commercial Mortgages | Commercial mortgages, other
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	1,036,229		984,038
Residential Mortgages
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	274,099		277,992
Allowance for credit losses	(2,218)	(2,106)	(2,194)	(1,868)	(1,905)	(1,845)
Consumer Loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	290,650		307,351
Allowance for credit losses	(3,565)	$ (3,501)	(3,242)	$ (3,213)	$ (3,152)	$ (2,865)
Consumer Loans | Home equity lines and loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	92,449		87,056
Consumer Loans | Indirect consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	189,504		210,423
Consumer Loans | Direct consumer loans
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	8,697		9,872
Commercial and industrial
Composition of loan portfolio [Abstract]
Total loans, net of deferred loan fees and costs	$ 289,266		$ 264,396

X

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

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- Definition

Amortized cost excluding accrued interest, after allowance for credit loss, of financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

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- Definition

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+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-5

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