LOANS AND ALLOWANCE FOR CREDIT LOSSES - Composition of Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	$ 66,337	$ 43,354
Nonaccrual Loans with no ACL	44,142	16,564
NTM Loans
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	20,619	13,019
Traditional Loans
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	45,718	30,335
Commercial | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	28,042	19,114
Nonaccrual Loans with no ACL	11,027	337
Commercial | Commercial real estate
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	6,471	0
Nonaccrual Loans with no ACL	6,471	0
Commercial | SBA
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	4,919	5,230
Nonaccrual Loans with no ACL	1,621	1,474
Commercial | Construction
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	0	0
Nonaccrual Loans with no ACL	0	0
Commercial | NTM Loans | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	0	0
Commercial | NTM Loans | Commercial real estate
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	0	0
Commercial | NTM Loans | SBA
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	0	0
Commercial | NTM Loans | Construction
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	0	0
Commercial | Traditional Loans | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	28,042	19,114
Commercial | Traditional Loans | Commercial real estate
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	6,471	0
Commercial | Traditional Loans | SBA
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	4,919	5,230
Commercial | Traditional Loans | Construction
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	0	0
Consumer | Single family residential mortgage
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	26,267	18,625
Nonaccrual Loans with no ACL	24,385	14,373
Consumer | Other consumer
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	638	385
Nonaccrual Loans with no ACL	638	380
Consumer | NTM Loans | Single family residential mortgage
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	20,619	13,019
Consumer | NTM Loans | Other consumer
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	0	0
Consumer | Traditional Loans | Single family residential mortgage
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	5,648	5,606
Consumer | Traditional Loans | Other consumer
Financing Receivable, Past Due [Line Items]
Total non-accrual loans	$ 638	$ 385