ACQUISITION OF FIRST NATIONAL BANKSHARES CORPORATION (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jan. 15, 2016 USD ($) Branch shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Business Acquisition [Line Items]
Goodwill	$ 35,371	$ 35,371		$ 33,796	$ 33,796
Estimated amortization of core deposit intangible [Abstract]
2016	711
2017	495
2018	475
2019	473
2020	334
Thereafter	$ 887
First National Bankshares [Member]
Business Acquisition [Line Items]
Merger consideration entitled to common stock (in shares) | shares			1.859
Goodwill			$ 1,580
Number of branch locations acquired | Branch			6
Net assets acquired via acquisition [Abstract]
Cash and due from banks			$ 11,912
Time deposits with other banks			4,473
Securities available for sale			76,612
Loans, net			132,798
Premises and equipment			5,839
Goodwill and other intangible assets			4,883
Other assets			824
Total assets acquired			237,341
Deposits			(205,174)
Repurchase agreements			(2,168)
FHLB borrowings			(1,347)
Subordinated debt			(5,307)
Other liabilities			(1,304)
Total liabilities assumed			(215,300)
Net assets acquired			22,041
Fair value of non-impaired loans acquired			125,669
Gross contractual amounts receivable			127,347
First National Bankshares [Member] | Core Deposits [Member]
Business Acquisition [Line Items]
Estimated useful life	10 years
Estimated amortization of core deposit intangible [Abstract]
2016			455
2017			428
2018			364
2019			309
2020			289
Thereafter			1,463
Total core deposit intangible acquired			$ 3,308