LOANS, Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for loan losses [Roll Forward]
Balance, beginning of period	$ 49,284	$ 47,583	$ 47,233
Charge-offs	(13,727)	(15,486)	(16,757)
Recoveries	5,924	6,350	6,123
Provision	8,430	10,837	10,984
Balance, end of period	49,911	49,284	47,583
Acquired Impaired [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	33	147	108
Charge-offs	0	(381)	(270)
Recoveries	0	0	0
Provision	130	267	309
Balance, end of period	163	33	147
Residential Portfolio Segment [Member] \| Consumer Mortgage [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	10,124	10,465	10,094
Charge-offs	(1,372)	(836)	(707)
Recoveries	60	136	50
Provision	1,457	359	1,028
Balance, end of period	10,269	10,124	10,465
Commercial Portfolio Segment [Member] \| Business Lending [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	18,522	17,257	17,220
Charge-offs	(2,334)	(3,566)	(4,959)
Recoveries	826	485	656
Provision	2,412	4,346	4,340
Balance, end of period	19,426	18,522	17,257
Consumer Portfolio Segment [Member] \| Consumer Indirect [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	14,366	13,468	13,782
Charge-offs	(7,631)	(8,382)	(8,456)
Recoveries	4,180	4,874	4,516
Provision	2,797	4,406	3,626
Balance, end of period	13,712	14,366	13,468
Consumer Portfolio Segment [Member] \| Consumer Direct [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	3,095	3,039	2,979
Charge-offs	(1,945)	(1,777)	(2,081)
Recoveries	710	807	849
Provision	1,395	1,026	1,292
Balance, end of period	3,255	3,095	3,039
Consumer Portfolio Segment [Member] \| Home Equity [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	2,144	2,107	2,399
Charge-offs	(445)	(544)	(284)
Recoveries	148	48	52
Provision	282	533	(60)
Balance, end of period	2,129	2,144	2,107
Unallocated Financing Receivables [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	1,000	1,100	651
Charge-offs	0	0	0
Recoveries	0	0	0
Provision	(43)	(100)	449
Balance, end of period	$ 957	$ 1,000	$ 1,100

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

+ References

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- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount of expense related to estimated loss from loan and lease transactions.

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