Quality of Non-Covered Loans (Excluding PCI Loans and Leases) (Parenthetical) (Detail) - Taxi Medallion Loans - Commercial and Industrial - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 483,000	$ 530,000
Loans 90 Days Or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 33,600	$ 35,500