Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail)

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Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2014
Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale $ 1,128,624 $ 530,926
Stock warrants   2
Mortgage-backed securities [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 584,157 217,059
U.S. government agency securities [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 172,793 83,536
Corporate bonds [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 16,940 20,835
U.S treasury securities [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 163  
Other securities [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 22,704 2,886
Equity security [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 450  
U.S. treasury securities [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 163 19,997
SBA loan pools securities [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 114,117 12,629
Municipal bonds-tax exempt [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 4,429 13,937
Municipal bonds-taxable [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 16,660 32,354
Collateralized mortgage obligations [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 196,211 127,693
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 172,956 103,533
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets [Member] | U.S. government agency securities [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 172,793 83,536
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets [Member] | U.S treasury securities [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 163  
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets [Member] | U.S. treasury securities [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale   19,997
Recurring Basis [Member] | Significant Observable Inputs with No Active Market with Identical Characteristics [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 954,500 426,645
Recurring Basis [Member] | Significant Observable Inputs with No Active Market with Identical Characteristics [Member] | Mortgage-backed securities [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 584,157 217,059
Recurring Basis [Member] | Significant Observable Inputs with No Active Market with Identical Characteristics [Member] | Corporate bonds [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 16,940 20,835
Recurring Basis [Member] | Significant Observable Inputs with No Active Market with Identical Characteristics [Member] | Other securities [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 22,704 2,886
Recurring Basis [Member] | Significant Observable Inputs with No Active Market with Identical Characteristics [Member] | SBA loan pools securities [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 114,117 12,629
Recurring Basis [Member] | Significant Observable Inputs with No Active Market with Identical Characteristics [Member] | Municipal bonds-tax exempt [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 3,711 13,189
Recurring Basis [Member] | Significant Observable Inputs with No Active Market with Identical Characteristics [Member] | Municipal bonds-taxable [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 16,660 32,354
Recurring Basis [Member] | Significant Unobservable Inputs [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 1,168 748
Stock warrants   2
Recurring Basis [Member] | Significant Unobservable Inputs [Member] | Equity security [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 450  
Recurring Basis [Member] | Significant Unobservable Inputs [Member] | Municipal bonds-tax exempt [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 718 748
Recurring Basis [Member] | Collateralized mortgage obligations [Member] | Significant Observable Inputs with No Active Market with Identical Characteristics [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale $ 196,211 $ 127,693