Recorded Investment in Loans Modified in TDRs (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	$ 3,706		$ 3,888
Commercial loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	3,421	[1]	3,888	[1]
Commercial loans | Software
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	600		651
Commercial loans | Hardware
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period			3,237
Commercial loans | Premium wine
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	405
Commercial loans | Other loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	2,416
Consumer loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	285
Consumer loans | Real estate secured loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	249
Consumer loans | Other loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs during the period	$ 36

[1] During the three months ended March 31, 2012, we had partial charge-offs of $0.8 million on loans classified as TDRs. There were no partial charge-offs on loans classified as TDRs during the three months ended March 31, 2011.