Annual report pursuant to Section 13 and 15(d)

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

v3.3.1.900
Securities - Summary of Investment Securities Available for Sale (Detail) - USD ($)
$ in Thousands
Dec. 31, 2015
Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost $ 700,627 $ 1,061,703
Gross Unrealized Gain 2,488 3,980
Gross Unrealized Loss 4,819 4,966
Estimated Fair Value 698,296 1,060,717
Municipal bonds-tax exempt [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 162,101 4,319
Gross Unrealized Gain 1,820 71
Gross Unrealized Loss 19 0
Estimated Fair Value 163,902 4,390
Municipal bonds-taxable [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 13,932 16,615
Gross Unrealized Gain 189 398
Gross Unrealized Loss 88 91
Estimated Fair Value 14,033 16,922
Corporate bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 5,017 17,018
Gross Unrealized Gain 0 2
Gross Unrealized Loss 24 72
Estimated Fair Value 4,993 16,948
Collateralized mortgage obligations [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 97,904 188,704
Gross Unrealized Gain 79 417
Gross Unrealized Loss 997 1,074
Estimated Fair Value 96,986 188,047
Mortgage-backed securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 286,450 571,678
Gross Unrealized Gain 392 2,811
Gross Unrealized Loss 2,461 1,203
Estimated Fair Value 284,381 573,286
U.S. government agency securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 48,478 129,857
Gross Unrealized Gain 0 172
Gross Unrealized Loss 656 1,822
Estimated Fair Value 47,822 128,207
SBA loan pool securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 63,670 109,983
Gross Unrealized Gain 7 52
Gross Unrealized Loss 411 588
Estimated Fair Value 63,266 109,447
U.S. treasury securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 159 163
Gross Unrealized Gain 1 0
Gross Unrealized Loss 0 0
Estimated Fair Value 160 163
Other securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 22,916 22,916
Gross Unrealized Gain 0 57
Gross Unrealized Loss 163 80
Estimated Fair Value $ 22,753 22,893
Equity securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost   450
Gross Unrealized Gain   0
Gross Unrealized Loss   36
Estimated Fair Value   $ 414