LOANS - Summary of Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss and Fee	$ 2,859,774	$ 2,816,464
Deferred loan fees, net	(4,006)	(4,020)
Total loans	2,855,768	2,812,444
Allowance for loan losses	(38,403)	(45,436)	$ (27,857)	$ (23,451)
Financing receivable, after allowance for credit loss	2,817,365	2,767,008
Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss and Fee	627,178	591,541
Allowance for loan losses	(6,417)	(4,847)	(4,742)	(4,743)
Commercial real estate:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss and Fee	997,958	993,912
Allowance for loan losses	(9,018)	(8,113)	(7,027)	(6,725)
Commercial real estate: | Nonfarm, nonresidential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss and Fee	955,348	944,021
Commercial real estate: | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss and Fee	42,610	49,891
Residential real estate:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss and Fee	648,586	643,601
Allowance for loan losses	(4,767)	(4,462)	(4,810)	(4,743)
Residential real estate: | Closed-end 1-4 family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss and Fee	456,610	455,920
Residential real estate: | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss and Fee	191,976	187,681
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss and Fee	581,598	582,641
Allowance for loan losses	(18,146)	(27,957)	(11,229)	(7,166)
Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss and Fee	4,454	4,769
Allowance for loan losses	$ (55)	$ (57)	$ (49)	$ (74)