Loans and Lease Finance Receivables and Allowance for Loan Losses - Schedule of Recorded Investment in, and Aging of, Past Due and Nonaccrual Loans, Excluding PCI Loans by Class of Loans (Parenthetical) (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Receivables [Abstract]
Nonaccruing loans, current	$ 20,100,000	$ 23,900,000
Nonaccruing loans, 30-59 days past due	3,700,000	473,000
Nonaccruing loans, 90+ days past due	8,500,000	14,700,000
Nonaccruing loans, 60-89 days past due		$ 854,000