Quarterly report pursuant to Section 13 or 15(d)

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

v3.3.0.814
Securities - Available for Sale Securities, Continuous Unrealized Loss Position, Fair value (Detail)
$ in Thousands
 9 Months Ended 12 Months Ended
Sep. 30, 2015
USD ($)
Security
Dec. 31, 2014
USD ($)
Security
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 478 $ 833
Available-for-Sale Within One Year, Estimated Fair Value $ 127,587 $ 276,192
Available-for-Sale Within One Year, Number of Securities | Security 35 60
Available-for-Sale More than One Year, Holding Period, Gross Unrealized Loss $ 1,326 $ 4,133
Available-for-Sale More than One Year, Holding Period, Estimated Fair Value $ 93,702 $ 184,458
Available-for-Sale More than One Year, Holding Period, Number of Securities | Security 38 73
Available-for-Sale, Gross Unrealized Loss $ 1,804 $ 4,966
Available-for-Sale, Estimated Fair Value $ 221,289 $ 460,650
Available-for-Sale, Number of Securities | Security 73 133
Municipal bonds-tax exempt [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 40  
Available-for-Sale Within One Year, Estimated Fair Value $ 3,864  
Available-for-Sale Within One Year, Number of Securities | Security 2  
Available-for-Sale More than One Year, Holding Period, Gross Unrealized Loss $ 0  
Available-for-Sale More than One Year, Holding Period, Estimated Fair Value $ 0  
Available-for-Sale More than One Year, Holding Period, Number of Securities | Security 0  
Available-for-Sale, Gross Unrealized Loss $ 40  
Available-for-Sale, Estimated Fair Value $ 3,864  
Available-for-Sale, Number of Securities | Security 2  
Municipal bonds-taxable [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 $ 374 $ 0
Available-for-Sale Within One Year, Number of Securities | Security 1 0
Available-for-Sale More than One Year, Holding Period, Gross Unrealized Loss $ 0 $ 91
Available-for-Sale More than One Year, Holding Period, Estimated Fair Value $ 0 $ 5,538
Available-for-Sale More than One Year, Holding Period, Number of Securities | Security 0 5
Available-for-Sale, Gross Unrealized Loss $ 0 $ 91
Available-for-Sale, Estimated Fair Value $ 374 $ 5,538
Available-for-Sale, Number of Securities | Security 1 5
Collateralized mortgage obligations [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 21 $ 350
Available-for-Sale Within One Year, Estimated Fair Value $ 20,276 $ 78,191
Available-for-Sale Within One Year, Number of Securities | Security 5 21
Available-for-Sale More than One Year, Holding Period, Gross Unrealized Loss $ 354 $ 724
Available-for-Sale More than One Year, Holding Period, Estimated Fair Value $ 27,156 $ 33,308
Available-for-Sale More than One Year, Holding Period, Number of Securities | Security 12 13
Available-for-Sale, Gross Unrealized Loss $ 375 $ 1,074
Available-for-Sale, Estimated Fair Value $ 47,432 $ 111,499
Available-for-Sale, Number of Securities | Security 17 34
Mortgage-backed securities [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 369 $ 288
Available-for-Sale Within One Year, Estimated Fair Value $ 76,181 $ 102,704
Available-for-Sale Within One Year, Number of Securities | Security 20 21
Available-for-Sale More than One Year, Holding Period, Gross Unrealized Loss $ 406 $ 915
Available-for-Sale More than One Year, Holding Period, Estimated Fair Value $ 22,447 $ 50,625
Available-for-Sale More than One Year, Holding Period, Number of Securities | Security 9 19
Available-for-Sale, Gross Unrealized Loss $ 775 $ 1,203
Available-for-Sale, Estimated Fair Value $ 98,628 $ 153,329
Available-for-Sale, Number of Securities | Security 29 40
U.S. government agency securities [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 24 $ 0
Available-for-Sale Within One Year, Estimated Fair Value $ 7,971 $ 5,000
Available-for-Sale Within One Year, Number of Securities | Security 3 1
Available-for-Sale More than One Year, Holding Period, Gross Unrealized Loss $ 287 $ 1,822
Available-for-Sale More than One Year, Holding Period, Estimated Fair Value $ 27,694 $ 73,142
Available-for-Sale More than One Year, Holding Period, Number of Securities | Security 9 26
Available-for-Sale, Gross Unrealized Loss $ 311 $ 1,822
Available-for-Sale, Estimated Fair Value $ 35,665 $ 78,142
Available-for-Sale, Number of Securities | Security 12 27
SBA loan pool securities [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 15 $ 155
Available-for-Sale Within One Year, Estimated Fair Value $ 13,911 $ 85,062
Available-for-Sale Within One Year, Number of Securities | Security 3 15
Available-for-Sale More than One Year, Holding Period, Gross Unrealized Loss $ 186 $ 433
Available-for-Sale More than One Year, Holding Period, Estimated Fair Value $ 7,474 $ 11,975
Available-for-Sale More than One Year, Holding Period, Number of Securities | Security 3 4
Available-for-Sale, Gross Unrealized Loss $ 201 $ 588
Available-for-Sale, Estimated Fair Value $ 21,385 $ 97,037
Available-for-Sale, Number of Securities | Security 6 19
Corporate bonds [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ 9 $ 4
Available-for-Sale Within One Year, Estimated Fair Value $ 5,010 $ 5,021
Available-for-Sale Within One Year, Number of Securities | Security 1 1
Available-for-Sale More than One Year, Holding Period, Gross Unrealized Loss $ 5 $ 68
Available-for-Sale More than One Year, Holding Period, Estimated Fair Value $ 7,994 $ 7,925
Available-for-Sale More than One Year, Holding Period, Number of Securities | Security 2 2
Available-for-Sale, Gross Unrealized Loss $ 14 $ 72
Available-for-Sale, Estimated Fair Value $ 13,004 $ 12,946
Available-for-Sale, Number of Securities | Security 3 3
Other 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, Holding Period, Gross Unrealized Loss $ 88 $ 80
Available-for-Sale More than One Year, Holding Period, Estimated Fair Value $ 937 $ 1,945
Available-for-Sale More than One Year, Holding Period, Number of Securities | Security 3 4
Available-for-Sale, Gross Unrealized Loss $ 88 $ 80
Available-for-Sale, Estimated Fair Value $ 937 $ 1,945
Available-for-Sale, Number of Securities | Security 3 4
Equity security [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss   $ 36
Available-for-Sale Within One Year, Estimated Fair Value   $ 214
Available-for-Sale Within One Year, Number of Securities | Security   1
Available-for-Sale More than One Year, Holding Period, Gross Unrealized Loss   $ 0
Available-for-Sale More than One Year, Holding Period, Estimated Fair Value   $ 0
Available-for-Sale More than One Year, Holding Period, Number of Securities | Security   0
Available-for-Sale, Gross Unrealized Loss   $ 36
Available-for-Sale, Estimated Fair Value   $ 214
Available-for-Sale, Number of Securities | Security   1