LOANS AND ALLOWANCE FOR LOAN LOSSES - Summary of the Company's Loan Portfolio by Category and Credit Quality Indicator (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 1,358,412	$ 1,258,779	$ 1,110,521
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,348,096	1,249,968
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	291	3,105
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	9,995	5,706
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	30	0
Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,112,565	1,047,074
Mortgage Loans on Real Estate [Member] | Construction and development [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	160,921	157,667	122,501
Mortgage Loans on Real Estate [Member] | 1-4 Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	286,976	276,922	252,003
Mortgage Loans on Real Estate [Member] | Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	50,770	51,283	50,770
Mortgage Loans on Real Estate [Member] | Farmland [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	20,902	23,838	14,130
Mortgage Loans on Real Estate [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	592,996	537,364	462,422
Mortgage Loans on Real Estate [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,106,439	1,040,512
Mortgage Loans on Real Estate [Member] | Pass [Member] | Construction and development [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	160,273	157,385
Mortgage Loans on Real Estate [Member] | Pass [Member] | 1-4 Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	285,196	275,492
Mortgage Loans on Real Estate [Member] | Pass [Member] | Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	50,770	51,283
Mortgage Loans on Real Estate [Member] | Pass [Member] | Farmland [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	18,638	19,611
Mortgage Loans on Real Estate [Member] | Pass [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	591,562	536,741
Mortgage Loans on Real Estate [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	69	2,847
Mortgage Loans on Real Estate [Member] | Special Mention [Member] | Construction and development [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Mortgage Loans on Real Estate [Member] | Special Mention [Member] | 1-4 Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	69	74
Mortgage Loans on Real Estate [Member] | Special Mention [Member] | Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Mortgage Loans on Real Estate [Member] | Special Mention [Member] | Farmland [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	2,773
Mortgage Loans on Real Estate [Member] | Special Mention [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Mortgage Loans on Real Estate [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	6,027	3,715
Mortgage Loans on Real Estate [Member] | Substandard [Member] | Construction and development [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	648	282
Mortgage Loans on Real Estate [Member] | Substandard [Member] | 1-4 Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,681	1,356
Mortgage Loans on Real Estate [Member] | Substandard [Member] | Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Mortgage Loans on Real Estate [Member] | Substandard [Member] | Farmland [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,264	1,454
Mortgage Loans on Real Estate [Member] | Substandard [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,434	623
Mortgage Loans on Real Estate [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	30	0
Mortgage Loans on Real Estate [Member] | Doubtful [Member] | Construction and development [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Mortgage Loans on Real Estate [Member] | Doubtful [Member] | 1-4 Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	30	0
Mortgage Loans on Real Estate [Member] | Doubtful [Member] | Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Mortgage Loans on Real Estate [Member] | Doubtful [Member] | Farmland [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Mortgage Loans on Real Estate [Member] | Doubtful [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	193,563	135,392	125,230
Commercial and industrial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	190,578	134,522
Commercial and industrial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Commercial and industrial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,985	870
Commercial and industrial [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	52,284	76,313	$ 83,465
Consumer [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	51,079	74,934
Consumer [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	222	258
Consumer [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	983	1,121
Consumer [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 0	$ 0