Loans and Lease Finance Receivables and Allowance for Loan Losses - Summary of Activity Related to Troubled Debt Restructurings (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Financing Receivable, Modifications [Line Items]
Total TDRs	$ 32,321	$ 60,333	$ 32,321	$ 60,333
Performing TDRs [Member]
Financing Receivable, Modifications [Line Items]
Beginning balance	37,321	45,376	42,687	53,589
New modifications	112	30	1,118	30
Payoffs and payments, net	(17,141)	(240)	(23,513)	(8,969)
TDRs returned to accrual status	0	0	0	516
TDRs placed on nonaccrual status	0	0	0	0
Ending balance	20,292	45,166	20,292	45,166
Nonperforming TDRs [Member]
Financing Receivable, Modifications [Line Items]
Beginning balance	12,360	16,774	12,622	20,285
New modifications	0	330	82	330
Charge-offs	0	0	(38)	0
Transfer to OREO	0	0	0	(842)
Payoffs and payments, net	(331)	(842)	(637)	(4,090)
TDRs returned to accrual status	0	(1,095)	0	(516)
TDRs placed on nonaccrual status	0	0	0	0
Ending balance	$ 12,029	$ 15,167	$ 12,029	$ 15,167