Loans and Allowance for Loan Losses Summary of Loans Modified in Troubled Debt Restructurings ("TDRs") by Portfolio Segment and Class of Financing Receivables (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	$ 22,433	$ 34,328
Software
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	5,860	2,021
Hardware
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	13,329	20,514
Venture capital/private equity
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	77	0
Premium wine
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	1,442	2,593
Commercial, Other
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	1,055	5,900
Commercial loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	21,763	31,028
Real estate secured loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	0	2,199
Consumer, Other
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	670	1,101
Consumer loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	$ 670	$ 3,300