LOANS AND ALLOWANCE FOR LOAN LOSSES - Receivables Past Due (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	$ 12,914	$ 12,043
Loans Past Due 90 Days or More and Still Accruing	27	13
Aging of the recorded investment in loans past due [Abstract]
Past Due	16,631	17,873
Loans Not Past Due	1,219,386	1,184,191
Total ending loans balance	1,237,387	1,203,482
30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	5,284	4,969
60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	4,153	6,383
90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	7,194	6,521
Loans acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	1,370	1,418
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	1,370	1,418
Commercial and agricultural:
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	178,534	177,027
Commercial and agricultural: | Loans acquired with deteriorated credit quality
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	0	0
Commercial mortgages:
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	604,166	570,156
Commercial mortgages: | Loans acquired with deteriorated credit quality
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	1,275	1,323
Commercial mortgages: | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	1,308	19
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	1,289	1,177
Loans Not Past Due	50,551	45,333
Total ending loans balance	51,840	46,510
Commercial mortgages: | Construction | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Commercial mortgages: | Construction | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	1,177
Commercial mortgages: | Construction | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	1,289	0
Commercial mortgages: | Construction | Loans acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	0	0
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	0	0
Commercial mortgages: | Commercial mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	5,639	5,454
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	6,824	7,524
Loans Not Past Due	544,227	514,799
Total ending loans balance	552,326	523,646
Commercial mortgages: | Commercial mortgages | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	941	652
Commercial mortgages: | Commercial mortgages | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	3,361	4,460
Commercial mortgages: | Commercial mortgages | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	2,522	2,412
Commercial mortgages: | Commercial mortgages | Loans acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	1,275	1,323
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	1,275	1,323
Residential mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	3,524	4,201
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	4,288	4,919
Loans Not Past Due	194,109	193,951
Total ending loans balance	198,492	198,965
Residential mortgages | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	2,276	2,100
Residential mortgages | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	254	436
Residential mortgages | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	1,758	2,383
Residential mortgages | Loans acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	95	95
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	95	95
Consumer Loans
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	256,195	257,334
Consumer Loans | Loans acquired with deteriorated credit quality
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	0	0
Consumer Loans | Credit cards
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	0	0
Loans Past Due 90 Days or More and Still Accruing	18	11
Aging of the recorded investment in loans past due [Abstract]
Past Due	48	23
Loans Not Past Due	1,361	1,453
Total ending loans balance	1,409	1,476
Consumer Loans | Credit cards | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	17	3
Consumer Loans | Credit cards | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	13	9
Consumer Loans | Credit cards | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	18	11
Consumer Loans | Credit cards | Loans acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	0	0
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	0	0
Consumer Loans | Home equity lines and loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	1,647	1,670
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	1,600	1,376
Loans Not Past Due	97,691	97,477
Total ending loans balance	99,291	98,853
Consumer Loans | Home equity lines and loans | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	289	227
Consumer Loans | Home equity lines and loans | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	209	0
Consumer Loans | Home equity lines and loans | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	1,102	1,149
Consumer Loans | Home equity lines and loans | Loans acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	0	0
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	0	0
Consumer Loans | Indirect consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	765	654
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	2,339	2,602
Loans Not Past Due	136,264	137,391
Total ending loans balance	138,603	139,993
Consumer Loans | Indirect consumer loans | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	1,538	1,773
Consumer Loans | Indirect consumer loans | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	313	287
Consumer Loans | Indirect consumer loans | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	488	542
Consumer Loans | Indirect consumer loans | Loans acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	0	0
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	0	0
Consumer Loans | Direct consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	31	45
Loans Past Due 90 Days or More and Still Accruing	0	0
Aging of the recorded investment in loans past due [Abstract]
Past Due	78	83
Loans Not Past Due	16,814	16,929
Total ending loans balance	16,892	17,012
Consumer Loans | Direct consumer loans | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	68	54
Consumer Loans | Direct consumer loans | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	2	7
Consumer Loans | Direct consumer loans | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	8	22
Consumer Loans | Direct consumer loans | Loans acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	0	0
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	0	0
Commercial and industrial | Commercial and agricultural:
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	0	0
Loans Past Due 90 Days or More and Still Accruing	9	2
Aging of the recorded investment in loans past due [Abstract]
Past Due	165	169
Loans Not Past Due	177,868	176,497
Total ending loans balance	178,033	176,666
Commercial and industrial | Commercial and agricultural: | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	155	160
Commercial and industrial | Commercial and agricultural: | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	1	7
Commercial and industrial | Commercial and agricultural: | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	9	2
Commercial and industrial | Commercial and agricultural: | Loans acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	0	0
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	0	0
Agricultural | Commercial and agricultural:
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Loans Not Past Due	501	361
Total ending loans balance	501	361
Agricultural | Commercial and agricultural: | 30 - 59 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Agricultural | Commercial and agricultural: | 60 - 89 Days Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Agricultural | Commercial and agricultural: | 90 Days or More Past Due
Aging of the recorded investment in loans past due [Abstract]
Past Due	0	0
Agricultural | Commercial and agricultural: | Loans acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	0	0
Aging of the recorded investment in loans past due [Abstract]
Total ending loans balance	$ 0	$ 0