Summary of Loans Modified in Troubled Debt Restructurings ("TDRs") by Portfolio Segment and Class of Financing Receivables (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	$ 23,487	$ 34,275
Commercial loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	19,904	13,208
Commercial loans | Software
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	2,459	1,142
Commercial loans | Hardware
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	12,193	5,183
Commercial loans | Premium wine
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	1,971	1,949
Commercial loans | Commercial Other Financing Receivable
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	3,281	4,934
Consumer loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	3,583	21,067
Consumer loans | Real estate secured loans
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	2,363	17,934
Consumer loans | Consumer Other Financing Receivable
Financing Receivable, Modifications [Line Items]
Loans modified in TDRs	$ 1,220	$ 3,133