Investment Securities - Summary of Investment Security Issuers (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Investments [Line Items]
Amortized Cost	$ 294,259	$ 403,005
Estimated Market Value	277,719	405,355
FHLB [Member]
Schedule of Investments [Line Items]
Amortized Cost	83,052
Estimated Market Value	78,729
Federal National Mortgage Association (Fannie Mae) [Member]
Schedule of Investments [Line Items]
Amortized Cost	81,693
Estimated Market Value	75,421
Federal Home Loan Mortgage Corporation (Freddie Mac) [Member]
Schedule of Investments [Line Items]
Amortized Cost	62,281
Estimated Market Value	$ 57,860