Quarterly report pursuant to Section 13 or 15(d)

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

v3.4.0.3
Securities - Available for Sale Securities, Continuous Unrealized Loss Position, Fair value (Detail)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2016
USD ($)
Security
Dec. 31, 2015
USD ($)
Security
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 467 $ 2,628
Available-for-Sale Within One Year, Estimated Fair Value $ 136,122 $ 359,531
Available-for-Sale Within One Year, Number of Securities | Security 33 104
Available-for-Sale More than One Year, Gross Unrealized Loss $ 531 $ 2,191
Available-for-Sale More than One Year, Estimated Fair Value $ 50,184 $ 87,120
Available-for-Sale More than One Year, Number of Securities | Security 25 36
Available-for-Sale, Gross Unrealized Loss $ 998 $ 4,819
Available-for-Sale, Estimated Fair Value $ 186,306 $ 446,651
Available-for-Sale, Number of Securities | Security 58 140
Municipal bonds-tax exempt [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 0 $ 19
Available-for-Sale Within One Year, Estimated Fair Value $ 854 $ 8,922
Available-for-Sale Within One Year, Number of Securities | Security 1 6
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 $ 19
Available-for-Sale, Estimated Fair Value $ 854 $ 8,922
Available-for-Sale, Number of Securities | Security 1 6
Municipal bonds-taxable [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss   $ 88
Available-for-Sale Within One Year, Estimated Fair Value   $ 7,106
Available-for-Sale Within One Year, Number of Securities | Security   4
Available-for-Sale More than One Year, Gross Unrealized Loss   $ 0
Available-for-Sale More than One Year, Estimated Fair Value   $ 0
Available-for-Sale More than One Year, Number of Securities | Security   0
Available-for-Sale, Gross Unrealized Loss   $ 88
Available-for-Sale, Estimated Fair Value   $ 7,106
Available-for-Sale, Number of Securities | Security   4
Mutual funds [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 0 $ 66
Available-for-Sale Within One Year, Estimated Fair Value $ 0 $ 21,820
Available-for-Sale Within One Year, Number of Securities | Security 0 3
Available-for-Sale More than One Year, Gross Unrealized Loss $ 87 $ 97
Available-for-Sale More than One Year, Estimated Fair Value $ 939 $ 928
Available-for-Sale More than One Year, Number of Securities | Security 3 3
Available-for-Sale, Gross Unrealized Loss $ 87 $ 163
Available-for-Sale, Estimated Fair Value $ 939 $ 22,748
Available-for-Sale, Number of Securities | Security 3 6
Collateralized mortgage obligations [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 43 $ 335
Available-for-Sale Within One Year, Estimated Fair Value $ 18,161 $ 48,970
Available-for-Sale Within One Year, Number of Securities | Security 7 18
Available-for-Sale More than One Year, Gross Unrealized Loss $ 179 $ 662
Available-for-Sale More than One Year, Estimated Fair Value $ 15,364 $ 32,964
Available-for-Sale More than One Year, Number of Securities | Security 8 13
Available-for-Sale, Gross Unrealized Loss $ 222 $ 997
Available-for-Sale, Estimated Fair Value $ 33,525 $ 81,934
Available-for-Sale, Number of Securities | Security 15 31
Mortgage-backed securities [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 281 $ 1,734
Available-for-Sale Within One Year, Estimated Fair Value $ 65,007 $ 193,931
Available-for-Sale Within One Year, Number of Securities | Security 12 52
Available-for-Sale More than One Year, Gross Unrealized Loss $ 166 $ 727
Available-for-Sale More than One Year, Estimated Fair Value $ 18,704 $ 21,659
Available-for-Sale More than One Year, Number of Securities | Security 8 9
Available-for-Sale, Gross Unrealized Loss $ 447 $ 2,461
Available-for-Sale, Estimated Fair Value $ 83,711 $ 215,590
Available-for-Sale, Number of Securities | Security 20 61
U.S. government agency securities [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 0 $ 201
Available-for-Sale Within One Year, Estimated Fair Value $ 0 $ 23,289
Available-for-Sale Within One Year, Number of Securities | Security 0 8
Available-for-Sale More than One Year, Gross Unrealized Loss $ 8 $ 455
Available-for-Sale More than One Year, Estimated Fair Value $ 7,984 $ 24,533
Available-for-Sale More than One Year, Number of Securities | Security 3 8
Available-for-Sale, Gross Unrealized Loss $ 8 $ 656
Available-for-Sale, Estimated Fair Value $ 7,984 $ 47,822
Available-for-Sale, Number of Securities | Security 3 16
SBA loan pool securities [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 125 $ 161
Available-for-Sale Within One Year, Estimated Fair Value $ 47,102 $ 50,499
Available-for-Sale Within One Year, Number of Securities | Security 12 12
Available-for-Sale More than One Year, Gross Unrealized Loss $ 91 $ 250
Available-for-Sale More than One Year, Estimated Fair Value $ 7,193 $ 7,036
Available-for-Sale More than One Year, Number of Securities | Security 3 3
Available-for-Sale, Gross Unrealized Loss $ 216 $ 411
Available-for-Sale, Estimated Fair Value $ 54,295 $ 57,535
Available-for-Sale, Number of Securities | Security 15 15
Corporate bonds [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 18 $ 24
Available-for-Sale Within One Year, Estimated Fair Value $ 4,998 $ 4,994
Available-for-Sale Within One Year, Number of Securities | Security 1 1
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 $ 18 $ 24
Available-for-Sale, Estimated Fair Value $ 4,998 $ 4,994
Available-for-Sale, Number of Securities | Security 1 1