Loans and Allowance for Loan Losses - Recorded Investment in Loans Modified in TDRs within Previous 12 months Subsequently Defaulted (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	$ 0	$ 635	$ 41	$ 635
Commercial loans
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	515	0	515
Consumer loans
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	120	41	120
Software
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	0	0	0
Hardware
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	515	0	515
Premium wine
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	0	0	0
Other
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	$ 0		$ 0