Quarterly report pursuant to Section 13 or 15(d)

Securities - Available for Sale Securities, Continuous Unrealized Loss Position, Fair value (Detail)

v3.7.0.1
Securities - Available for Sale Securities, Continuous Unrealized Loss Position, Fair value (Detail)
$ in Thousands
 6 Months Ended 12 Months Ended
Jun. 30, 2017
USD ($)
Security
Dec. 31, 2016
USD ($)
Security
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 2,442 $ 4,496
Available-for-Sale Within One Year, Estimated Fair Value $ 291,460 $ 320,260
Available-for-Sale Within One Year, Number of Securities | Security 106 128
Available-for-Sale More than One Year, Gross Unrealized Loss $ 693 $ 757
Available-for-Sale More than One Year, Estimated Fair Value $ 30,102 $ 26,991
Available-for-Sale More than One Year, Number of Securities | Security 19 15
Available-for-Sale, Gross Unrealized Loss $ 3,135 $ 5,253
Available-for-Sale, Estimated Fair Value $ 321,562 $ 347,251
Available-for-Sale, Number of Securities | Security 125 143
Municipal bonds-tax exempt [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 118 $ 1,995
Available-for-Sale Within One Year, Estimated Fair Value $ 5,128 $ 125,004
Available-for-Sale Within One Year, Number of Securities | Security 7 54
Available-for-Sale More than One Year, Gross Unrealized Loss $ 0 $ 0
Available-for-Sale More than One Year, Estimated Fair Value $ 0 $ 0
Available-for-Sale More than One Year, Number of Securities | Security 0 0
Available-for-Sale, Gross Unrealized Loss $ 118 $ 1,995
Available-for-Sale, Estimated Fair Value $ 5,128 $ 125,004
Available-for-Sale, Number of Securities | Security 7 54
Municipal bonds-taxable [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 0 $ 9
Available-for-Sale Within One Year, Estimated Fair Value $ 154 $ 2,904
Available-for-Sale Within One Year, Number of Securities | Security 1 2
Available-for-Sale More than One Year, Gross Unrealized Loss $ 0 $ 0
Available-for-Sale More than One Year, Estimated Fair Value $ 0 $ 0
Available-for-Sale More than One Year, Number of Securities | Security 0 0
Available-for-Sale, Gross Unrealized Loss $ 0 $ 9
Available-for-Sale, Estimated Fair Value $ 154 $ 2,904
Available-for-Sale, Number of Securities | Security 1 2
Mutual funds [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 290 $ 413
Available-for-Sale Within One Year, Estimated Fair Value $ 21,596 $ 21,478
Available-for-Sale Within One Year, Number of Securities | Security 3 4
Available-for-Sale More than One Year, Gross Unrealized Loss $ 111 $ 109
Available-for-Sale More than One Year, Estimated Fair Value $ 914 $ 916
Available-for-Sale More than One Year, Number of Securities | Security 3 3
Available-for-Sale, Gross Unrealized Loss $ 401 $ 522
Available-for-Sale, Estimated Fair Value $ 22,510 $ 22,394
Available-for-Sale, Number of Securities | Security 6 7
Mortgage-backed securities [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 1,432 $ 1,345
Available-for-Sale Within One Year, Estimated Fair Value $ 189,400 $ 102,647
Available-for-Sale Within One Year, Number of Securities | Security 62 38
Available-for-Sale More than One Year, Gross Unrealized Loss $ 64 $ 112
Available-for-Sale More than One Year, Estimated Fair Value $ 6,868 $ 11,350
Available-for-Sale More than One Year, Number of Securities | Security 2 3
Available-for-Sale, Gross Unrealized Loss $ 1,496 $ 1,457
Available-for-Sale, Estimated Fair Value $ 196,268 $ 113,997
Available-for-Sale, Number of Securities | Security 64 41
Collateralized mortgage obligations [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 560 $ 676
Available-for-Sale Within One Year, Estimated Fair Value $ 67,725 $ 60,786
Available-for-Sale Within One Year, Number of Securities | Security 30 27
Available-for-Sale More than One Year, Gross Unrealized Loss $ 376 $ 326
Available-for-Sale More than One Year, Estimated Fair Value $ 18,424 $ 10,579
Available-for-Sale More than One Year, Number of Securities | Security 12 7
Available-for-Sale, Gross Unrealized Loss $ 936 $ 1,002
Available-for-Sale, Estimated Fair Value $ 86,149 $ 71,365
Available-for-Sale, Number of Securities | Security 42 34
U.S. government agency securities [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 42 $ 58
Available-for-Sale Within One Year, Estimated Fair Value $ 7,457 $ 7,441
Available-for-Sale Within One Year, Number of Securities | Security 3 3
Available-for-Sale More than One Year, Gross Unrealized Loss $ 0 $ 0
Available-for-Sale More than One Year, Estimated Fair Value $ 0 $ 0
Available-for-Sale More than One Year, Number of Securities | Security 0 0
Available-for-Sale, Gross Unrealized Loss $ 42 $ 58
Available-for-Sale, Estimated Fair Value $ 7,457 $ 7,441
Available-for-Sale, Number of Securities | Security 3 3
SBA loan pool securities [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 0 $ 0
Available-for-Sale Within One Year, Estimated Fair Value $ 0 $ 0
Available-for-Sale Within One Year, Number of Securities | Security 0 0
Available-for-Sale More than One Year, Gross Unrealized Loss $ 142 $ 210
Available-for-Sale More than One Year, Estimated Fair Value $ 3,896 $ 4,146
Available-for-Sale More than One Year, Number of Securities | Security 2 2
Available-for-Sale, Gross Unrealized Loss $ 142 $ 210
Available-for-Sale, Estimated Fair Value $ 3,896 $ 4,146
Available-for-Sale, Number of Securities | Security 2 2