Loans and Lease Finance Receivables and Allowance for Loan Losses - Summary of Activity Related to Loans Held-for-Sale (Detail) (Loans Held-for-Sale [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Loans Held-for-Sale [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance, beginning of period	$ 3,667	$ 0
Originations of mortgage loans	0	485
Sales of mortgage loans	0	(485)
Transfer of mortgage loans to held for investment	0	0
Sales of other loans	(3,667)	0
Transfers of other loans to held-for-sale	0	3,667
Write-down of loans held-for-sale	0	0
Balance, end of period	$ 0	$ 3,667