LOANS, Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Allowance for loan losses [Roll Forward]
Beginning balance	$ 49,618	$ 47,451	$ 47,583	$ 47,233
Charge-offs	(3,267)	(3,224)	(10,636)	(9,447)
Recoveries	1,567	1,442	4,844	4,594
Provision	2,215	2,314	8,342	5,603
Ending balance	50,133	47,983	50,133	47,983
Acquired Impaired [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	33	63	147	108
Charge-offs	0	0	(368)	(184)
Recoveries	0	0	0	0
Provision	15	(11)	269	128
Ending balance	48	52	48	52
Residential Portfolio Segment [Member] \| Business Lending [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	18,439	17,230	17,257	17,220
Charge-offs	(73)	(124)	(2,000)	(1,062)
Recoveries	93	127	404	481
Provision	321	399	3,119	993
Ending balance	18,780	17,632	18,780	17,632
Commercial Portfolio Segment [Member] \| Consumer Mortgage [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	10,473	10,197	10,465	10,094
Charge-offs	(144)	(198)	(588)	(541)
Recoveries	46	24	109	42
Provision	(205)	280	184	708
Ending balance	10,170	10,303	10,170	10,303
Consumer Portfolio Segment [Member] \| Consumer Indirect [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	14,424	13,918	13,468	13,782
Charge-offs	(2,364)	(2,328)	(6,031)	(5,969)
Recoveries	1,190	1,058	3,688	3,379
Provision	1,719	1,130	3,844	2,586
Ending balance	14,969	13,778	14,969	13,778
Consumer Portfolio Segment [Member] \| Consumer Direct [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	3,164	2,945	3,039	2,979
Charge-offs	(465)	(574)	(1,324)	(1,463)
Recoveries	223	221	612	648
Provision	299	426	894	854
Ending balance	3,221	3,018	3,221	3,018
Consumer Portfolio Segment [Member] \| Home Equity [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	2,015	2,242	2,107	2,399
Charge-offs	(221)	0	(325)	(228)
Recoveries	15	12	31	44
Provision	225	(52)	221	(13)
Ending balance	2,034	2,202	2,034	2,202
Unallocated Financing Receivables [Member]
Allowance for loan losses [Roll Forward]
Beginning balance	1,070	856	1,100	651
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	(159)	142	(189)	347
Ending balance	$ 911	$ 998	$ 911	$ 998

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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