Fair Value Disclosures - Schedule of Financial Instruments Carried at Fair Value (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	$ 818,495	$ 794,543
Total assets measured at fair value on a recurring basis	819,497	796,051
Other real estate owned	2,121	3,591
Loans held for sale	35,425	54,782
Impaired loans (collateral dependent),net	62,884	46,499
Total assets measured at fair value on a nonrecurring basis	100,430	104,872
Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other liabilities	2,708	3,380
GSE | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	2,993	35,010
CMO
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	314,839	261,216
CMO | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	314,839	261,215
FNMA MBS
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	395,960	405,764
FNMA MBS | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	395,960	405,764
FHLMC MBS
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	77,144	63,514
FHLMC MBS | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	77,144	63,515
GNMA MBS
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	26,939	28,416
GNMA MBS | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	26,939	28,416
Other investments | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	620	623
Other assets | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	1,002	1,508
Quoted Prices in Active Markets for Identical Asset (Level 1)
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total assets measured at fair value on a recurring basis	620	623
Other real estate owned	0	0
Loans held for sale	0	0
Impaired loans (collateral dependent),net	0	0
Total assets measured at fair value on a nonrecurring basis	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other liabilities	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | GSE | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | CMO | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | FNMA MBS | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | FHLMC MBS | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | GNMA MBS | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Quoted Prices in Active Markets for Identical Asset (Level 1) | Other investments | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	620	623
Quoted Prices in Active Markets for Identical Asset (Level 1) | Other assets | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Significant Other Observable Inputs (Level 2)
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total assets measured at fair value on a recurring basis	818,877	795,428
Other real estate owned	0	0
Loans held for sale	35,425	54,782
Impaired loans (collateral dependent),net	0	0
Total assets measured at fair value on a nonrecurring basis	35,425	54,782
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other liabilities	2,708	3,380
Significant Other Observable Inputs (Level 2) | GSE | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	2,993	35,010
Significant Other Observable Inputs (Level 2) | CMO | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	314,839	261,215
Significant Other Observable Inputs (Level 2) | FNMA MBS | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	395,960	405,764
Significant Other Observable Inputs (Level 2) | FHLMC MBS | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	77,144	63,515
Significant Other Observable Inputs (Level 2) | GNMA MBS | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	26,939	28,416
Significant Other Observable Inputs (Level 2) | Other investments | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Significant Other Observable Inputs (Level 2) | Other assets | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	1,002	1,508
Significant Unobservable Inputs (Level 3)
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Total assets measured at fair value on a recurring basis	0	0
Other real estate owned	2,121	3,591
Loans held for sale	0	0
Impaired loans (collateral dependent),net	62,884	46,499
Total assets measured at fair value on a nonrecurring basis	65,005	50,090
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other liabilities	0	0
Significant Unobservable Inputs (Level 3) | GSE | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | CMO | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | FNMA MBS | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | FHLMC MBS | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | GNMA MBS | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | Other investments | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | Other assets | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Investment securities available for sale	$ 0	$ 0