Quarterly report pursuant to Section 13 or 15(d)

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

v3.2.0.727
Securities - Summary of Investment Securities Available for Sale (Detail) - USD ($)
$ in Thousands
Jun. 30, 2015
Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost $ 729,763 $ 1,061,703
Gross Unrealized Gain 2,832 3,980
Gross Unrealized Loss 3,912 4,966
Estimated Fair Value 728,683 1,060,717
Collateralized mortgage obligations [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 154,968 188,704
Gross Unrealized Gain 1,061 417
Gross Unrealized Loss 660 1,074
Estimated Fair Value 155,369 188,047
Municipal bonds-tax exempt [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 3,589 4,319
Gross Unrealized Gain 37 71
Gross Unrealized Loss 0 0
Estimated Fair Value 3,626 4,390
Municipal bonds-taxable [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 15,607 16,615
Gross Unrealized Gain 271 398
Gross Unrealized Loss 46 91
Estimated Fair Value 15,832 16,922
Corporate bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 17,019 17,018
Gross Unrealized Gain 1 2
Gross Unrealized Loss 44 72
Estimated Fair Value 16,976 16,948
Mortgage-backed securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 379,574 571,678
Gross Unrealized Gain 1,374 2,811
Gross Unrealized Loss 1,380 1,203
Estimated Fair Value 379,568 573,286
U.S. government agency securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 63,969 129,857
Gross Unrealized Gain 4 172
Gross Unrealized Loss 1,312 1,822
Estimated Fair Value 62,661 128,207
SBA loan pool securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 71,960 109,983
Gross Unrealized Gain 83 52
Gross Unrealized Loss 357 588
Estimated Fair Value 71,686 109,447
U.S. treasury securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 161 163
Gross Unrealized Gain 1 0
Gross Unrealized Loss 0 0
Estimated Fair Value 162 163
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 113 80
Estimated Fair Value $ 22,803 22,893
Equity security [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost   450
Gross Unrealized Gain   0
Gross Unrealized Loss   36
Estimated Fair Value   $ 414