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		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	$ 4,224	$ 3,600	$ 6,974	$ 3,700
Commercial loans
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	4,154	2,311	6,904	2,411
Commercial loans | Software
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	0	0	100
Commercial loans | Hardware
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	4,154	452	4,154	452
Commercial loans | Premium wine
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	1,859	0	1,859
Commercial loans | Other
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	0	2,750	0
Consumer loans
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	$ 70	$ 1,289	$ 70	$ 1,289