Assets and Liabilities Measured at Fair Value on Recurring and Non-Recurring Basis Based on Fair Value Hierarchy (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Common stock warrant liability	$ 10,800	$ 7,500	$ 2,350	$ 2,850	$ 2,000	$ 1,403
Investment securities, available for sale			3,060
Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Nonrecurring fair value measurements, Assets	1,359
Real estate owned, net | Discontinued Operations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Nonrecurring fair value measurements, Assets	95		830
Commercial Real Estate Loans Held For Investment | Discontinued Operations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Nonrecurring fair value measurements, Assets			51
Quoted Prices in Active Markets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Common stock warrant liability
Investment securities, available for sale			3,060
Quoted Prices in Active Markets (Level 1) | Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Nonrecurring fair value measurements, Assets
Quoted Prices in Active Markets (Level 1) | Real estate owned, net | Discontinued Operations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Nonrecurring fair value measurements, Assets
Quoted Prices in Active Markets (Level 1) | Commercial Real Estate Loans Held For Investment | Discontinued Operations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Nonrecurring fair value measurements, Assets
Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Common stock warrant liability
Investment securities, available for sale
Significant Other Observable Inputs (Level 2) | Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Nonrecurring fair value measurements, Assets	1,359
Significant Other Observable Inputs (Level 2) | Real estate owned, net | Discontinued Operations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Nonrecurring fair value measurements, Assets
Significant Other Observable Inputs (Level 2) | Commercial Real Estate Loans Held For Investment | Discontinued Operations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Nonrecurring fair value measurements, Assets
Significant Unobservable Inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Common stock warrant liability	10,800		2,350
Investment securities, available for sale
Significant Unobservable Inputs (Level 3) | Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Nonrecurring fair value measurements, Assets
Significant Unobservable Inputs (Level 3) | Real estate owned, net | Discontinued Operations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Nonrecurring fair value measurements, Assets	95		830
Significant Unobservable Inputs (Level 3) | Commercial Real Estate Loans Held For Investment | Discontinued Operations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Nonrecurring fair value measurements, Assets			$ 51