Securities - Schedule of Gross Unrealized Losses and Fair Value of Securities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Unrealized Losses	$ (386)	$ (238)
12 Months or More Unrealized Losses	(581)	(406)
Total Unrealized Losses	(967)	(644)
Less Than 12 Estimated Fair Value	44,540	31,163
12 Months or More Estimated Fair Value	8,682	6,681
Total Estimated Fair Value	53,222	37,844
U.S. government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Unrealized Losses	(6)
Total Unrealized Losses	(6)
Less Than 12 Estimated Fair Value	4,994
Total Estimated Fair Value	4,994
State, county and municipal securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Unrealized Losses	(199)	(90)
12 Months or More Unrealized Losses	(11)
Total Unrealized Losses	(210)	(90)
Less Than 12 Estimated Fair Value	15,595	10,134
12 Months or More Estimated Fair Value	505
Total Estimated Fair Value	16,100	10,134
Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
12 Months or More Unrealized Losses	(547)	(406)
Total Unrealized Losses	(547)	(406)
Less Than 12 Estimated Fair Value		100
12 Months or More Estimated Fair Value	4,560	6,681
Total Estimated Fair Value	4,560	6,781
Mortgage backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months Unrealized Losses	(181)	(148)
12 Months or More Unrealized Losses	(23)
Total Unrealized Losses	(204)	(148)
Less Than 12 Estimated Fair Value	23,951	20,929
12 Months or More Estimated Fair Value	3,617
Total Estimated Fair Value	$ 27,568	$ 20,929