LOANS AND ALLOWANCE FOR LOAN LOSSES - Allowances (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance:	$ 14,253	$ 14,260	$ 13,686
Charge Offs	(2,571)	(2,830)	(1,631)
Recoveries	457	386	634
Net (charge offs) recoveries	(2,114)	(2,444)	(997)
Provision	9,022	2,437	1,571
Ending balance	21,161	14,253	14,260
Ending allowance balance attributable to loans:
Individually evaluated for impairment				$ 5,937	$ 876
Collectively evaluated for impairment				15,195	13,293
Allowance for loan losses	14,253	14,260	13,686	21,161	14,253
Loans:
Loans individually evaluated for impairment				13,926	11,926
Loans collectively evaluated for impairment				1,300,864	1,190,138
Total ending loans balance				1,315,582	1,203,482
Commercial, and Agricultural
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance:	1,589	1,831	1,460
Charge Offs	(96)	(217)	(186)
Recoveries	109	92	96
Net (charge offs) recoveries	13	(125)	(90)
Provision	5,374	(117)	461
Ending balance	6,976	1,589	1,831
Ending allowance balance attributable to loans:
Individually evaluated for impairment				5,135	0
Collectively evaluated for impairment				1,841	1,589
Allowance for loan losses	1,589	1,831	1,460	6,976	1,589
Loans:
Loans individually evaluated for impairment				6,133	693
Loans collectively evaluated for impairment				193,443	176,334
Total ending loans balance				199,576	177,027
Commercial mortgages:
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance:	7,270	7,112	6,326
Charge Offs	(419)	(911)	(104)
Recoveries	5	10	131
Net (charge offs) recoveries	(414)	(901)	27
Provision	1,658	1,059	759
Ending balance	8,514	7,270	7,112
Ending allowance balance attributable to loans:
Individually evaluated for impairment				802	735
Collectively evaluated for impairment				7,683	6,476
Allowance for loan losses	7,270	7,112	6,326	8,514	7,270
Loans:
Loans individually evaluated for impairment				7,302	10,382
Loans collectively evaluated for impairment				638,080	558,451
Total ending loans balance				646,174	570,156
Residential Mortgages
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance:	1,523	1,464	1,572
Charge Offs	(225)	(65)	(47)
Recoveries	30	0	0
Net (charge offs) recoveries	(195)	(65)	(47)
Provision	(12)	124	(61)
Ending balance	1,316	1,523	1,464
Ending allowance balance attributable to loans:
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				1,316	1,498
Allowance for loan losses	1,523	1,464	1,572	1,316	1,523
Loans:
Loans individually evaluated for impairment				427	396
Loans collectively evaluated for impairment				194,510	198,474
Total ending loans balance				194,937	198,965
Consumer Loans
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance:	3,871	3,853	4,328
Charge Offs	(1,831)	(1,637)	(1,294)
Recoveries	313	284	407
Net (charge offs) recoveries	(1,518)	(1,353)	(887)
Provision	2,002	1,371	412
Ending balance	4,355	3,871	3,853
Ending allowance balance attributable to loans:
Individually evaluated for impairment				0	141
Collectively evaluated for impairment				4,355	3,730
Allowance for loan losses	3,871	3,853	$ 4,328	4,355	3,871
Loans:
Loans individually evaluated for impairment				64	455
Loans collectively evaluated for impairment				274,831	256,879
Total ending loans balance				274,895	257,334
Loans acquired with deteriorated credit quality
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance:	84
Ending balance	29	84
Ending allowance balance attributable to loans:
Allowance for loan losses	84	84		29	84
Loans:
Total ending loans balance				792	1,418
Loans acquired with deteriorated credit quality | Commercial, and Agricultural
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance:	0
Ending balance	0	0
Ending allowance balance attributable to loans:
Allowance for loan losses	0	0		0	0
Loans:
Total ending loans balance				0	0
Loans acquired with deteriorated credit quality | Commercial mortgages:
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance:	59
Ending balance	29	59
Ending allowance balance attributable to loans:
Allowance for loan losses	59	59		29	59
Loans:
Total ending loans balance				792	1,323
Loans acquired with deteriorated credit quality | Residential Mortgages
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance:	25
Ending balance	0	25
Ending allowance balance attributable to loans:
Allowance for loan losses	25	25		0	25
Loans:
Total ending loans balance				0	95
Loans acquired with deteriorated credit quality | Consumer Loans
Allowance for loan losses, by portfolio segment [Roll Forward]
Beginning balance:	0
Ending balance	0	0
Ending allowance balance attributable to loans:
Allowance for loan losses	$ 0	$ 0		0	0
Loans:
Total ending loans balance				$ 0	$ 0