Recorded Investment in Loans Modified in TDRs within the Previous 12 months that Subsequently Defaulted (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	$ 6,967
Commercial loans
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	3,834
Commercial loans | Hardware
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	1,885
Commercial loans | Premium wine
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	1,949
Consumer loans
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	3,133
Consumer loans | Other loans
Financing Receivable, Modifications [Line Items]
TDRs modified within the previous 12 months that defaulted in the period	$ 3,133