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LOANS AND ALLOWANCE FOR LOAN LOSSES - Troubled Debt Restructuring (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020 USD ($) loan	Sep. 30, 2020 USD ($) loan	Sep. 30, 2019 USD ($) loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans | loan	3	15	2
Pre-modification outstanding recorded investment	$ 1,458	$ 5,100	$ 4,360
Post-modification outstanding recorded investment	$ 1,458	$ 5,100	$ 4,360
Commercial and agricultural: | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans | loan	2	4
Pre-modification outstanding recorded investment	$ 1,138	$ 2,068
Post-modification outstanding recorded investment	$ 1,138	$ 2,068
Commercial loan portfolio | Commercial mortgages, other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans | loan	0	4	1
Pre-modification outstanding recorded investment	$ 0	$ 1,297	$ 4,223
Post-modification outstanding recorded investment	$ 0	$ 1,297	$ 4,223
Commercial loan portfolio | Residential mortgages
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans | loan	1	4
Pre-modification outstanding recorded investment	$ 320	$ 997
Post-modification outstanding recorded investment	$ 320	$ 997
Consumer loans: | Home equity lines and loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans | loan	0	3	1
Pre-modification outstanding recorded investment	$ 0	$ 738	$ 137
Post-modification outstanding recorded investment	$ 0	$ 738	$ 137

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

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Amount, after troubled debt restructuring, of modified financing receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

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Amount, before troubled debt restructuring, of financing receivable to be modified.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

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