Loans and Allowance for Credit Losses - Summary of Amortized Cost of Nonaccrual Loans with No Related Allowance (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans	$ 58,219	$ 87,823
Amortized Cost of Nonaccrual Loans with no related Allowance	50,460	42,122
Commercial and Industrial Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans	20,724	33,769
Amortized Cost of Nonaccrual Loans with no related Allowance	17,250	9,916
Specialty Lending Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans	16,999	19,437
Amortized Cost of Nonaccrual Loans with no related Allowance	16,387	242
Commercial Real Estate Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans	15,067	28,386
Amortized Cost of Nonaccrual Loans with no related Allowance	11,394	25,733
Consumer Real Estate Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans	4,731	5,345
Amortized Cost of Nonaccrual Loans with no related Allowance	4,731	5,345
Consumer Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans	92	88
Amortized Cost of Nonaccrual Loans with no related Allowance	92	88
Credit Cards Portfolio [Member]
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans	606	798
Amortized Cost of Nonaccrual Loans with no related Allowance	$ 606	$ 798