Annual report pursuant to Section 13 and 15(d)

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

v3.3.1.900
Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)
$ in Thousands
Dec. 31, 2015
Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale $ 698,296 $ 1,060,717
Municipal bonds-tax exempt [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 163,902 4,390
Municipal bonds-taxable [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 14,033 16,922
Collateralized mortgage obligations [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 96,986 188,047
U.S. government agency securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 47,822 128,207
Other securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 22,753 22,893
Equity securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale   414
Recurring Basis [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 698,296 1,060,717
Recurring Basis [Member] | SBA loan pools securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 63,266 109,447
Recurring Basis [Member] | Municipal bonds-tax exempt [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 163,902 4,390
Recurring Basis [Member] | Municipal bonds-taxable [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 14,033 16,922
Recurring Basis [Member] | Collateralized mortgage obligations [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 96,986 188,047
Recurring Basis [Member] | Mortgage-backed securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 284,381 573,286
Recurring Basis [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 47,822 128,207
Recurring Basis [Member] | Corporate bonds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 4,993 16,948
Recurring Basis [Member] | U.S treasury securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 160 163
Recurring Basis [Member] | Other securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 22,753 22,893
Recurring Basis [Member] | Equity securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale   414
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 22,913 23,056
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets [Member] | SBA loan pools securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 0 0
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets [Member] | Municipal bonds-tax exempt [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 0 0
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets [Member] | Municipal bonds-taxable [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 0 0
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets [Member] | Collateralized mortgage obligations [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 0 0
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets [Member] | Mortgage-backed securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 0 0
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 0 0
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets [Member] | Corporate bonds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 0 0
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 160 163
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets [Member] | Other securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 22,753 22,893
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets [Member] | Equity securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale   0
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 675,383 1,036,538
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 63,266 109,447
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 163,902 3,681
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 14,033 16,922
Recurring Basis [Member] | Significant Observable Inputs with No Active Market with Identical Characteristics [Member] | Collateralized mortgage obligations [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 96,986 188,047
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 284,381 573,286
Recurring Basis [Member] | Significant Observable Inputs with No Active Market with Identical Characteristics [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 47,822 128,207
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 4,993 16,948
Recurring Basis [Member] | Significant Observable Inputs with No Active Market with Identical Characteristics [Member] | U.S treasury securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 0 0
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 0 0
Recurring Basis [Member] | Significant Observable Inputs with No Active Market with Identical Characteristics [Member] | Equity securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale   0
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 0 1,123
Recurring Basis [Member] | Significant Unobservable Inputs [Member] | SBA loan pools securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 0 0
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 0 709
Recurring Basis [Member] | Significant Unobservable Inputs [Member] | Municipal bonds-taxable [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 0 0
Recurring Basis [Member] | Significant Unobservable Inputs [Member] | Collateralized mortgage obligations [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 0 0
Recurring Basis [Member] | Significant Unobservable Inputs [Member] | Mortgage-backed securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 0 0
Recurring Basis [Member] | Significant Unobservable Inputs [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 0 0
Recurring Basis [Member] | Significant Unobservable Inputs [Member] | Corporate bonds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 0 0
Recurring Basis [Member] | Significant Unobservable Inputs [Member] | U.S treasury securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale 0 0
Recurring Basis [Member] | Significant Unobservable Inputs [Member] | Other securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale $ 0 0
Recurring Basis [Member] | Significant Unobservable Inputs [Member] | Equity securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total securities available for sale   $ 414