LOANS AND ASSET QUALITY - Non-accrual loans (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	$ 3,751	$ 3,706	$ 3,706
Transfer into non-accrual	1,239	1,187
Loans paid down/payoffs	(476)	(846)
Loans brought to accrual status	(291)	(312)
Loans charged off	(357)	(1,378)	(1,913)
Balance	3,866	2,357	3,751
Commercial and Industrial
Financing Receivable Nonaccrual Status [Roll Forward]
Transfer into non-accrual	48
Balance	48
Commercial Real Estate
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	647	300	300
Transfer into non-accrual		325
Loans paid down/payoffs	(16)	(10)
Loans brought to accrual status	(132)
Loans charged off			(364)
Balance	499	615	647
Consumer and Indirect
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	456	831	831
Transfer into non-accrual	586	759
Loans paid down/payoffs	(144)	(482)
Loans brought to accrual status	(159)	(177)
Loans charged off	(354)	(524)	(695)
Balance	385	407	456
Residential Real estate
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	2,648	2,575	2,575
Transfer into non-accrual	605	103
Loans paid down/payoffs	(316)	(354)
Loans brought to accrual status		(135)
Loans charged off	(3)	(854)	(854)
Balance	$ 2,934	$ 1,335	$ 2,648