Quarterly report pursuant to Section 13 or 15(d)

Securities - Schedule of Amortized Cost and Estimated Fair Value of Investment Securities by Contractual Maturity (Detail)

v3.2.0.727
Securities - Schedule of Amortized Cost and Estimated Fair Value of Investment Securities by Contractual Maturity (Detail) - USD ($)
$ in Thousands
Jun. 30, 2015
Dec. 31, 2014
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within one year, Amortized Cost $ 11,998  
Available-for-Sale Over one year through five years, Amortized Cost 17,329  
Available-for-Sale Over five years through ten years, Amortized Cost 98,196  
Available-for-Sale Over ten years, Amortized Cost 44,782  
Available-for-Sale, Amortized Cost 729,763 $ 1,061,703
Available-for-Sale Within one year, Estimated Fair Value 11,973  
Available-for-Sale Over one year through five years, Estimated Fair Value 17,208  
Available-for-Sale Over five years through ten years, Estimated Fair Value 97,498  
Available-for-Sale Over ten years, Estimated Fair Value 44,264  
Securities available for sale 728,683 1,060,717
Collateralized mortgage obligations [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale, Amortized Cost 154,968 188,704
Securities available for sale 155,369 188,047
Mortgage-backed securities [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale, Amortized Cost 379,574 571,678
Securities available for sale 379,568 573,286
Other securities [Member]    
Summary of Investment Holdings [Line Items]    
Available-for-Sale, Amortized Cost 22,916 22,916
Securities available for sale $ 22,803 $ 22,893