Loans and Allowance for Loan Losses Recorded Investment in Loans Modified in TDRs (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	$ 13,848,000	[1]	$ 28,723,000	[1]	$ 13,599,000	[1]
Loans classified as TDRs, charge-offs	11,100,000		14,300,000		2,800,000
Loans modified in TDRs	22,433,000		34,328,000
Software
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	4,932,000		1,939,000		615,000
Loans modified in TDRs	5,860,000		2,021,000
Hardware
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	8,143,000		20,514,000		4,018,000
Loans modified in TDRs	13,329,000		20,514,000
Venture capital/private equity
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	77,000		0		0
Loans modified in TDRs	77,000		0
Premium wine
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	0		1,024,000		1,949,000
Loans modified in TDRs	1,442,000		2,593,000
Commercial, Other
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	690,000		4,878,000		3,884,000
Loans modified in TDRs	1,055,000		5,900,000
Commercial loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	13,842,000		28,355,000		10,466,000
Loans modified in TDRs	21,763,000		31,028,000
Real estate secured loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	0		368,000		0
Loans modified in TDRs	0		2,199,000
Consumer, Other
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	6,000		0		3,133,000
Loans modified in TDRs	670,000		1,101,000
Consumer loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	6,000		368,000		3,133,000
Loans modified in TDRs	670,000		3,300,000
Forgiveness Of Principal
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period			9,000,000
Payment Deferrals Granted
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period			$ 19,000,000

[1] During 2013 , 2012, and 2011 we had partial charge-offs of $11.1 million, $14.3 million, and $2.8 million respectively, on loans classified as TDRs.