Quality of Non-Covered Loans (Excluding PCI Loans) (Parenthetical) (Detail) - Non-Covered Loans - USD ($) $ in Thousands	Sep. 30, 2016		Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 69,973		$ 53,430
Loans 90 Days Or More Past Due | Purchased Credit-Impaired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	950,000		969,000
Financing Receivable, 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	26,572	[1]	$ 6,605
Financing Receivable, 30-89 Days Past Due | Purchased Credit-Impaired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 4,000

[1] Excludes $4,000 and $950,000 of non-covered PCI loans that were 30-89 days past due and 90 days or more past due, respectively.