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
Mar. 31, 2017
Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost $ 550,748 $ 521,053
Gross Unrealized Gain 1,320 1,164
Gross Unrealized Loss 4,058 5,253
Estimated Fair Value 548,010 516,964
Municipal bonds-tax exempt [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 159,203 159,789
Gross Unrealized Gain 431 236
Gross Unrealized Loss 860 1,995
Estimated Fair Value 158,774 158,030
Municipal bonds-taxable [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 1,045 13,391
Gross Unrealized Gain 0 319
Gross Unrealized Loss 8 9
Estimated Fair Value 1,037 13,701
Corporate bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 5,008 5,010
Gross Unrealized Gain 14 5
Gross Unrealized Loss 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 526 522
Estimated Fair Value 22,390 22,394
Mortgage-backed securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 262,713 230,489
Gross Unrealized Gain 862 598
Gross Unrealized Loss 1,480 1,457
Estimated Fair Value 262,095 229,630
Collateralized mortgage obligations [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 87,855 77,447
Gross Unrealized Gain 13 6
Gross Unrealized Loss 940 1,002
Estimated Fair Value 86,928 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 53 58
Estimated Fair Value 7,446 7,441
SBA loan pool securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 4,354 4,356
Gross Unrealized Gain 0 0
Gross Unrealized Loss 191 210
Estimated Fair Value 4,163 4,146
U.S. treasury securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 155 156
Gross Unrealized Gain 0 0
Gross Unrealized Loss 0
Estimated Fair Value 155 156
Collateralized home equity conversion mortgages [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Estimated Fair Value $ 50,500 $ 52,900