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	6 Months Ended
	Jun. 30, 2014 troubled_debt_restructuring	Dec. 31, 2013
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	15
Loans modified in TDRs	$ 20,315	$ 22,433
Commercial loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	19,979	21,763
Consumer loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	336	670
Software
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	13,053	5,860
Hardware
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	4,108	13,329
Venture capital/private equity
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	0	77
Premium wine
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	2,014	1,442
Other
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	804	1,055
Consumer loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	$ 336	$ 670