LOANS AND ALLOWANCE FOR LOAN LOSSES - Loans where there was a payment default within twelve months following the modification - (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) item	Dec. 31, 2016 USD ($) item	Dec. 31, 2015 USD ($) item
Loans by class modified as troubled debt restructurings for which there was a payment default within twelve months following the modification
Number of Loans | item	6	5	7
Recorded Investment	$ 720	$ 409	$ 1,183
Period of contractually past due loans under the modified terms, to be considered in payment default	90 days
Additional disclosures
Recorded investment in loans modified other than troubled debt restructurings	$ 21,072	$ 12,484
Commercial real estate | Other
Loans by class modified as troubled debt restructurings for which there was a payment default within twelve months following the modification
Number of Loans | item	4	2	3
Recorded Investment	$ 511	$ 149	$ 863
Residential | 1-4 family
Loans by class modified as troubled debt restructurings for which there was a payment default within twelve months following the modification
Number of Loans | item	2	2	2
Recorded Investment	$ 209	$ 250	$ 232
Residential | Home equity
Loans by class modified as troubled debt restructurings for which there was a payment default within twelve months following the modification
Number of Loans | item		1	2
Recorded Investment		$ 10	$ 88