Loans and Allowance for Credit Losses - Summary of Amortized Cost of Nonaccrual Loans with No Related Allowance (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	$ 97,029	$ 56,347
Amortized Cost of Non-Accrual Loans with no related Allowance	68,190
Commercial and Industrial Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	42,613
Amortized Cost of Non-Accrual Loans with no related Allowance	22,102
Specialty Lending Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	1,455
Amortized Cost of Non-Accrual Loans with no related Allowance	1,011
Commercial Real Estate Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	46,379
Amortized Cost of Non-Accrual Loans with no related Allowance	38,495
Consumer Real Estate Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	5,521
Amortized Cost of Non-Accrual Loans with no related Allowance	5,521
Consumer Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	184
Amortized Cost of Non-Accrual Loans with no related Allowance	184
Credit Cards Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	808
Amortized Cost of Non-Accrual Loans with no related Allowance	808
Leases and Other Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	69
Amortized Cost of Non-Accrual Loans with no related Allowance	$ 69