Investment Securities - Schedule of Amortized Cost and Approximate Fair Value of Investment Securities Classified as Held to Maturity (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 14,015	$ 6,579
Gross Unrealized Gains
Gross Unrealized Losses	(308)	(593)
Fair Value	13,707	5,986
Obligations of other U.S. government agencies and corporations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	3,975	3,972
Gross Unrealized Gains
Gross Unrealized Losses	(194)	(380)
Fair Value	3,781	3,592
Mortgage-backed securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	2,570	2,607
Gross Unrealized Gains
Gross Unrealized Losses	(114)	(213)
Fair Value	2,456	2,394
Obligations of state and political subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	7,470
Gross Unrealized Gains
Fair Value	$ 7,470