Quarterly report pursuant to Section 13 or 15(d)

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

v3.7.0.1
Securities - Summary of Investment Securities Available for Sale (Detail) - USD ($)
$ in Thousands
Jun. 30, 2017
Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost $ 571,611 $ 521,053
Gross Unrealized Gain 3,370 1,164
Gross Unrealized Loss 3,135 5,253
Estimated Fair Value 571,846 516,964
Municipal bonds-tax exempt [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 158,614 159,789
Gross Unrealized Gain 2,567 236
Gross Unrealized Loss 118 1,995
Estimated Fair Value 161,063 158,030
Municipal bonds-taxable [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 531 13,391
Gross Unrealized Gain 6 319
Gross Unrealized Loss 0 9
Estimated Fair Value 537 13,701
Corporate bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 5,006 5,010
Gross Unrealized Gain 16 5
Gross Unrealized Loss 0 0
Estimated Fair Value 5,022 5,015
Mutual funds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 22,916 22,916
Gross Unrealized Gain 0 0
Gross Unrealized Loss 401 522
Estimated Fair Value 22,515 22,394
Mortgage-backed securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 280,494 230,489
Gross Unrealized Gain 767 598
Gross Unrealized Loss 1,496 1,457
Estimated Fair Value 279,765 229,630
Collateralized mortgage obligations [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 92,360 77,447
Gross Unrealized Gain 14 6
Gross Unrealized Loss 936 1,002
Estimated Fair Value 91,438 76,451
U.S. government agency securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 7,499 7,499
Gross Unrealized Gain 0 0
Gross Unrealized Loss 42 58
Estimated Fair Value 7,457 7,441
SBA loan pool securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 4,037 4,356
Gross Unrealized Gain 0 0
Gross Unrealized Loss 142 210
Estimated Fair Value 3,895 4,146
U.S. treasury securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 154 156
Gross Unrealized Gain 0 0
Gross Unrealized Loss 0 0
Estimated Fair Value 154 156
Collateralized home equity conversion mortgages [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Estimated Fair Value $ 9,100 $ 52,900