Securities - Amortized Cost and Fair Value of Securities by Contractual Maturity (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Available for Sale, Amortized Cost, Due in less than one year	$ 100
Available for Sale, Amortized Cost, Due after one year through five years	817
Available for Sale, Amortized Cost, Due after five years through ten years	8,438
Available for Sale, Amortized Cost, Due after ten years	29,923
Available for Sale, Amortized Cost, Total	39,278
Available for Sale, Fair Value, Due in less than one year	100
Available for Sale, Fair Value, Due after one year through five years	832
Available for Sale, Fair Value, Due after five years through ten years	8,349
Available for Sale, Fair Value, Due after ten years	29,762
Available for Sale, Fair Value, Total	39,043
Gross Amortized Cost, Securities Available for Sale	658,458	637,940
Fair Value, Available for Sale	641,611	643,050
Mortgage-Backed Securities of U.S. Government Sponsored Entities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost, Securities Available for Sale	129,468	186,404
Fair Value, Available for Sale	126,735	189,255
Collateralized Mortgage Obligations of U.S. Government Sponsored Entities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost, Securities Available for Sale	383,392	352,731
Fair Value, Available for Sale	369,421	354,259
Private Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost, Securities Available for Sale	29,800
Fair Value, Available for Sale	29,574
Private Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost, Securities Available for Sale	76,520	96,258
Fair Value, Available for Sale	$ 76,838	$ 96,931