CREDIT QUALITY ASSESSMENT - Non-accrual Loans (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Nonaccrual [Line Items]
Average non-accrual loans for the period	$ 104,183	$ 72,562
Contractual interest income due on non- accrual loans during the period	1,732	18,301
Commercial real estate: | Commercial investor real estate
Financing Receivable, Nonaccrual [Line Items]
Average non-accrual loans for the period	44,002	26,849
Contractual interest income due on non- accrual loans during the period	649	6,547
Commercial real estate: | Commercial owner-occupied real estate
Financing Receivable, Nonaccrual [Line Items]
Average non-accrual loans for the period	9,939	6,605
Contractual interest income due on non- accrual loans during the period	185	2,741
Commercial real estate: | Commercial AD&C
Financing Receivable, Nonaccrual [Line Items]
Average non-accrual loans for the period	15,010	4,267
Contractual interest income due on non- accrual loans during the period	256	4,505
Commercial Business
Financing Receivable, Nonaccrual [Line Items]
Average non-accrual loans for the period	18,040	16,532
Contractual interest income due on non- accrual loans during the period	428	2,858
Residential real estate: | Residential mortgage
Financing Receivable, Nonaccrual [Line Items]
Average non-accrual loans for the period	9,903	11,634
Contractual interest income due on non- accrual loans during the period	110	918
Residential real estate: | Residential construction
Financing Receivable, Nonaccrual [Line Items]
Average non-accrual loans for the period	0	0
Contractual interest income due on non- accrual loans during the period	0	0
Consumer
Financing Receivable, Nonaccrual [Line Items]
Average non-accrual loans for the period	7,289	6,675
Contractual interest income due on non- accrual loans during the period	$ 104	$ 732