Annual report pursuant to Section 13 and 15(d)

Securities - Summary of Investment Securities Available for Sale (Detail)

v3.6.0.2
Securities - Summary of Investment Securities Available for Sale (Detail) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost $ 521,053 $ 700,627
Gross Unrealized Gain 1,164 2,488
Gross Unrealized Loss 5,253 4,819
Estimated Fair Value 516,964 698,296
Collateralized mortgage obligations [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 77,447 97,904
Gross Unrealized Gain 6 79
Gross Unrealized Loss 1,002 997
Estimated Fair Value 76,451 96,986
Mortgage-backed securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 230,489 286,450
Gross Unrealized Gain 598 392
Gross Unrealized Loss 1,457 2,461
Estimated Fair Value 229,630 284,381
U.S. government agency securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 7,499 48,478
Gross Unrealized Gain 0 0
Gross Unrealized Loss 58 656
Estimated Fair Value 7,441 47,822
SBA loan pool securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 4,356 63,670
Gross Unrealized Gain 0 7
Gross Unrealized Loss 210 411
Estimated Fair Value 4,146 63,266
Municipal bonds-tax exempt [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 159,789 162,101
Gross Unrealized Gain 236 1,820
Gross Unrealized Loss 1,995 19
Estimated Fair Value 158,030 163,902
Municipal bonds-taxable [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 13,391 13,932
Gross Unrealized Gain 319 189
Gross Unrealized Loss 9 88
Estimated Fair Value 13,701 14,033
Corporate bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 5,010 5,017
Gross Unrealized Gain 5 0
Gross Unrealized Loss 0 24
Estimated Fair Value 5,015 4,993
U.S. treasury securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 156 159
Gross Unrealized Gain 0 1
Gross Unrealized Loss 0 0
Estimated Fair Value 156 160
Other securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 22,916 22,916
Gross Unrealized Gain 0 0
Gross Unrealized Loss 522 163
Estimated Fair Value $ 22,394 $ 22,753