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	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	$ 2,036	$ 1,988	$ 6,967
Hardware
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	1,627	1,868	1,885
Venture capital/private equity
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	38	0	0
Premium wine
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	0	1,949
Commercial, Other
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	365	0	0
Commercial loans
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	2,030	1,868	3,834
Real estate secured loans
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	0	120	0
Other Loans
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	6	0	3,133
Consumer loans
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	$ 6	$ 120	$ 3,133