LOANS, Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for loan losses [Roll Forward]
Balance, beginning of period	$ 47,233	$ 45,401	$ 45,341
Charge-offs	(16,757)	(12,183)	(12,071)
Recoveries	6,123	5,939	5,684
Provision	10,984	8,076	6,447
Balance, end of period	47,583	47,233	45,401
Acquired Impaired [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	108	168	173
Charge-offs	(270)	(97)	(103)
Recoveries	0	0	0
Provision	309	37	98
Balance, end of period	147	108	168
Residential Portfolio Segment [Member] \| Consumer Mortgage [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	10,094	10,198	10,286
Charge-offs	(707)	(647)	(1,374)
Recoveries	50	115	80
Provision	1,028	428	1,206
Balance, end of period	10,465	10,094	10,198
Commercial Portfolio Segment [Member] \| Business Lending [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	17,220	15,749	15,787
Charge-offs	(4,959)	(1,872)	(2,146)
Recoveries	656	616	877
Provision	4,340	2,727	1,231
Balance, end of period	17,257	17,220	15,749
Consumer Portfolio Segment [Member] \| Consumer Indirect [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	13,782	12,422	11,544
Charge-offs	(8,456)	(7,643)	(6,714)
Recoveries	4,516	4,168	3,943
Provision	3,626	4,835	3,649
Balance, end of period	13,468	13,782	12,422
Consumer Portfolio Segment [Member] \| Consumer Direct [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	2,979	2,997	3,083
Charge-offs	(2,081)	(1,706)	(1,490)
Recoveries	849	901	722
Provision	1,292	787	682
Balance, end of period	3,039	2,979	2,997
Consumer Portfolio Segment [Member] \| Home Equity [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	2,399	2,666	2,701
Charge-offs	(284)	(218)	(244)
Recoveries	52	139	62
Provision	(60)	(188)	147
Balance, end of period	2,107	2,399	2,666
Unallocated Financing Receivables [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	651	1,201	1,767
Charge-offs	0	0	0
Recoveries	0	0	0
Provision	449	(550)	(566)
Balance, end of period	$ 1,100	$ 651	$ 1,201

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
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