Investment Securities - Amortized Cost and Estimated Fair Values of Investment Securities (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Amortized Cost	$ 207,455,000	$ 204,313,000
Available-for-sale securities, Gross Unrealized Gains	2,289,000	1,543,000
Available-for-sale securities, Gross Unrealized Losses	(4,065,000)	(5,901,000)
Available-for-sale securities, Fair Value	205,678,778	199,955,367
U.S. Government Corporations and Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Amortized Cost	50,595,000	50,598,000
Available-for-sale securities, Gross Unrealized Gains	20,000	18,000
Available-for-sale securities, Gross Unrealized Losses	(1,480,000)	(2,170,000)
Available-for-sale securities, Fair Value	49,135,000	48,446,000
States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Amortized Cost	62,129,000	60,049,000
Available-for-sale securities, Gross Unrealized Gains	2,085,000	1,421,000
Available-for-sale securities, Gross Unrealized Losses	(513,000)	(1,056,000)
Available-for-sale securities, Fair Value	63,701,000	60,414,000
Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Amortized Cost	94,567,000	93,501,000
Available-for-sale securities, Gross Unrealized Gains	151,000	72,000
Available-for-sale securities, Gross Unrealized Losses	(2,071,000)	(2,673,000)
Available-for-sale securities, Fair Value	92,647,000	90,900,000
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Amortized Cost	164,000	165,000
Available-for-sale securities, Gross Unrealized Gains	33,000	32,000
Available-for-sale securities, Gross Unrealized Losses	(1,000)	(2,000)
Available-for-sale securities, Fair Value	$ 196,000	$ 195,000