LOANS AND ALLOWANCE FOR LOAN LOSSES - Summary of Credit Exposure (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 1,651,863	$ 1,359,544	$ 1,307,375
Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,633,511	1,329,802
Special mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	7,729	23,213
Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	10,623	6,529
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total loans	248,758	197,508	192,663
Commercial and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	246,621	196,890
Commercial and industrial | Special mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	807	348
Commercial and industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,330	270
Construction and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	229,307	196,774	201,067
Construction and development | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	227,862	196,515
Construction and development | Special mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	259
Construction and development | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,445	0
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	599,153	418,137	393,314
Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	587,603	412,488
Commercial real estate | Special mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,165	1,135
Commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	6,385	4,514
Farmland
Financing Receivable, Recorded Investment [Line Items]
Total loans	65,209	59,023	54,349
Farmland | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	64,797	58,623
Farmland | Special mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	50	226
Farmland | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	362	174
1-4 family residential
Financing Receivable, Recorded Investment [Line Items]
Total loans	392,456	374,371	365,889
1-4 family residential | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	391,556	373,154
1-4 family residential | Special mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	293	442
1-4 family residential | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	607	775
Multi-family residential
Financing Receivable, Recorded Investment [Line Items]
Total loans	38,523	36,574	23,235
Multi-family residential | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	37,284	16,073
Multi-family residential | Special mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,239	20,284
Multi-family residential | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	217
Consumer and Overdrafts
Financing Receivable, Recorded Investment [Line Items]
Total loans	54,273	51,561
Consumer and Overdrafts | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	54,183	51,409
Consumer and Overdrafts | Special mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	45	65
Consumer and Overdrafts | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	45	87
Agricultural
Financing Receivable, Recorded Investment [Line Items]
Total loans	24,184	25,596	$ 24,449
Agricultural | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	23,605	24,650
Agricultural | Special mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	130	454
Agricultural | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 449	$ 492