Fair value of SBA loans and the sensitivity to immediate changes in those assumptions (Detail) (Commercial Loans [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Commercial Loans [Member]
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Servicing Asset at Amortized Cost	$ 695	$ 1,087
Interests Continued To Be Held By Transferor Fair Value	2,414	3,336
Weighted average life (in years)	3 years 1 month 0 days	3 years 2 months 0 days
Servicing Assets And Servicing Liabilities At Fair Value Assumptions Used To Estimate Fair Value Prepayment Speed	5.60%	5.50%
Impact on fair value of 10% adverse change	(33)	(46)
Impact on fair value of 20% adverse change	(68)	(95)
Servicing Assets And Servicing Liabilities At Fair Value Assumptions Used To Estimate Fair Value Discount Rate	13.00%	13.00%
Impact on fair value of 10% adverse change	(72)	(103)
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 20 Percent Adverse Change in Discount Rate	$ (148)	$ (210)

The carrying amount (fair value) as of the balance sheet date of the transferor's interests in transferred financial assets (typically securitized receivables, generally not involved in the collection of principal) following transfer of significant portions of such financial instruments to other parties. Such interests could be ancillary cash flows and interest-only strips.

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The hypothetical financial impact of a 10 percent adverse change of the discount rate on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date.

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Amortized carrying amount (balance) as of the balance sheet date of an asset representing net future revenues from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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The estimated speed of prepayments of principal on financial assets which may be one of the factors applied in estimating the fair value of servicing assets and servicing liabilities.

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Weighted average life of financial assets and financial liabilities, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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