LOANS AND ALLOWANCE FOR LOAN LOSSES - Summary of the Company's Loan Portfolio by Category and Credit Quality Indicator (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 1,494,919	$ 1,400,825	$ 1,272,950
Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,485,134	1,391,054
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	218	236
Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	9,362	9,462
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	205	73
Total mortgage loans on real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,199,233	1,143,944
Total mortgage loans on real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,193,464	1,138,315
Total mortgage loans on real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	69
Total mortgage loans on real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,564	5,487
Total mortgage loans on real estate | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	205	73
Total mortgage loans on real estate | Construction and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	171,483	157,946	162,337
Total mortgage loans on real estate | Construction and development | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	170,907	157,360
Total mortgage loans on real estate | Construction and development | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total mortgage loans on real estate | Construction and development | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	443	586
Total mortgage loans on real estate | Construction and development | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	133	0
Total mortgage loans on real estate | 1-4 Family
Financing Receivable, Recorded Investment [Line Items]
Total loans	299,061	287,137	277,978
Total mortgage loans on real estate | 1-4 Family | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	297,532	285,692
Total mortgage loans on real estate | 1-4 Family | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	69
Total mortgage loans on real estate | 1-4 Family | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,457	1,303
Total mortgage loans on real estate | 1-4 Family | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	72	73
Total mortgage loans on real estate | Multifamily
Financing Receivable, Recorded Investment [Line Items]
Total loans	57,487	50,501	54,504
Total mortgage loans on real estate | Multifamily | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	57,378	50,501
Total mortgage loans on real estate | Multifamily | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total mortgage loans on real estate | Multifamily | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	109	0
Total mortgage loans on real estate | Multifamily | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total mortgage loans on real estate | Farmland
Financing Receivable, Recorded Investment [Line Items]
Total loans	24,457	21,356	20,725
Total mortgage loans on real estate | Farmland | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	22,193	19,092
Total mortgage loans on real estate | Farmland | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total mortgage loans on real estate | Farmland | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,264	2,264
Total mortgage loans on real estate | Farmland | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total mortgage loans on real estate | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	646,745	627,004	554,155
Total mortgage loans on real estate | Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	645,454	625,670
Total mortgage loans on real estate | Commercial real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Total mortgage loans on real estate | Commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,291	1,334
Total mortgage loans on real estate | Commercial real estate | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total loans	255,476	210,924	135,965
Commercial and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	252,462	207,941
Commercial and industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Commercial and industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,014	2,983
Commercial and industrial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Consumer
Financing Receivable, Recorded Investment [Line Items]
Total loans	40,210	45,957	$ 67,286
Consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	39,208	44,798
Consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	218	167
Consumer | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	784	992
Consumer | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 0	$ 0