Loans and Allowance for Credit Losses - Summary of Amortized Cost of Nonaccrual Loans with No Related Allowance (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	$ 82,245	$ 56,347
Amortized Cost of Non-Accrual Loans with no related Allowance	56,227
Commercial and Industrial Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	39,982
Amortized Cost of Non-Accrual Loans with no related Allowance	19,683
Specialty Lending Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	538
Amortized Cost of Non-Accrual Loans with no related Allowance	538
Commercial Real Estate Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	35,531
Amortized Cost of Non-Accrual Loans with no related Allowance	29,812
Consumer Real Estate Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	5,148
Amortized Cost of Non-Accrual Loans with no related Allowance	5,148
Consumer Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	208
Amortized Cost of Non-Accrual Loans with no related Allowance	208
Credit Cards Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	815
Amortized Cost of Non-Accrual Loans with no related Allowance	815
Leases and Other Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Non- Accrual Loans	23
Amortized Cost of Non-Accrual Loans with no related Allowance	$ 23