LOANS - Summary of Risk Category of Loans by Class of Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Risk Category Of Loans [Line Items]
Loans	$ 2,859,774	$ 2,816,464
Construction and land development
Risk Category Of Loans [Line Items]
Loans	627,178	591,541
Commercial real estate:
Risk Category Of Loans [Line Items]
Loans	997,958	993,912
Residential real estate:
Risk Category Of Loans [Line Items]
Loans	648,586	643,601
Commercial and industrial
Risk Category Of Loans [Line Items]
Loans	581,598	582,641
Consumer and other
Risk Category Of Loans [Line Items]
Loans	4,454	4,769
Pass
Risk Category Of Loans [Line Items]
Loans	2,806,649	2,764,188
Pass | Construction and land development
Risk Category Of Loans [Line Items]
Loans	627,178	591,293
Pass | Commercial and industrial
Risk Category Of Loans [Line Items]
Loans	543,565	539,442
Pass | Consumer and other
Risk Category Of Loans [Line Items]
Loans	4,454	4,769
Special Mention
Risk Category Of Loans [Line Items]
Loans	5,431	3,013
Special Mention | Construction and land development
Risk Category Of Loans [Line Items]
Loans	0	248
Special Mention | Commercial and industrial
Risk Category Of Loans [Line Items]
Loans	600	943
Special Mention | Consumer and other
Risk Category Of Loans [Line Items]
Loans	0	0
Substandard
Risk Category Of Loans [Line Items]
Loans	47,694	49,263
Substandard | Construction and land development
Risk Category Of Loans [Line Items]
Loans	0	0
Substandard | Commercial and industrial
Risk Category Of Loans [Line Items]
Loans	37,433	42,256
Substandard | Consumer and other
Risk Category Of Loans [Line Items]
Loans	0	0
Nonfarm, nonresidential | Commercial real estate:
Risk Category Of Loans [Line Items]
Loans	955,348	944,021
Nonfarm, nonresidential | Pass | Commercial real estate:
Risk Category Of Loans [Line Items]
Loans	946,120	941,260
Nonfarm, nonresidential | Special Mention | Commercial real estate:
Risk Category Of Loans [Line Items]
Loans	4,012	997
Nonfarm, nonresidential | Substandard | Commercial real estate:
Risk Category Of Loans [Line Items]
Loans	5,216	1,764
Other | Commercial real estate:
Risk Category Of Loans [Line Items]
Loans	42,610	49,891
Other | Pass | Commercial real estate:
Risk Category Of Loans [Line Items]
Loans	42,610	49,891
Other | Special Mention | Commercial real estate:
Risk Category Of Loans [Line Items]
Loans	0	0
Other | Substandard | Commercial real estate:
Risk Category Of Loans [Line Items]
Loans	0	0
Closed-end 1-4 family | Residential real estate:
Risk Category Of Loans [Line Items]
Loans	456,610	455,920
Closed-end 1-4 family | Pass | Residential real estate:
Risk Category Of Loans [Line Items]
Loans	453,892	452,363
Closed-end 1-4 family | Special Mention | Residential real estate:
Risk Category Of Loans [Line Items]
Loans	819	825
Closed-end 1-4 family | Substandard | Residential real estate:
Risk Category Of Loans [Line Items]
Loans	1,899	2,732
Other | Residential real estate:
Risk Category Of Loans [Line Items]
Loans	191,976	187,681
Other | Pass | Residential real estate:
Risk Category Of Loans [Line Items]
Loans	188,830	185,170
Other | Special Mention | Residential real estate:
Risk Category Of Loans [Line Items]
Loans	0	0
Other | Substandard | Residential real estate:
Risk Category Of Loans [Line Items]
Loans	$ 3,146	$ 2,511