LOANS - Activity in Allowance for Loan Losses by Portfolio Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 45,436	$ 23,451
Provision for loan losses	13,022	5,055
Loans charged-off	(20,530)	(653)
Recoveries	475	4
Total ending allowance balance	38,403	27,857
Construction and land development
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	4,847	4,743
Provision for loan losses	1,570	(1)
Loans charged-off	0	0
Recoveries	0	0
Total ending allowance balance	6,417	4,742
Commercial real estate:
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	8,113	6,725
Provision for loan losses	905	302
Loans charged-off	0	0
Recoveries	0	0
Total ending allowance balance	9,018	7,027
Residential real estate:
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	4,462	4,743
Provision for loan losses	312	80
Loans charged-off	(8)	(15)
Recoveries	1	2
Total ending allowance balance	4,767	4,810
Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	27,957	7,166
Provision for loan losses	10,222	4,631
Loans charged-off	(20,501)	(568)
Recoveries	468	0
Total ending allowance balance	18,146	11,229
Consumer and other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	57	74
Provision for loan losses	13	43
Loans charged-off	(21)	(70)
Recoveries	6	2
Total ending allowance balance	$ 55	$ 49