Fair Value Measurements - Balances of Assets Measured at Fair Value on a Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value	$ 105,163	$ 89,456
U.S. Agency and Mortgage-Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value	86,583	73,218
Fair Value, Measurements, Recurring [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value	105,163	89,456
Fair Value, Measurements, Recurring [Member] \| U.S. Agency and Mortgage-Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value	86,583	73,218
Fair Value, Measurements, Recurring [Member] \| Obligations of States and Political Subdivisions [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value	18,577	16,235
Fair Value, Measurements, Recurring [Member] \| Corporate Equity Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value	3	3
Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value	3	3
Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| U.S. Agency and Mortgage-Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value
Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Obligations of States and Political Subdivisions [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value
Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Corporate Equity Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value	3	3
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value	105,160	89,453
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| U.S. Agency and Mortgage-Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value	86,583	73,218
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Obligations of States and Political Subdivisions [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value	18,577	16,235
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Corporate Equity Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| U.S. Agency and Mortgage-Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Obligations of States and Political Subdivisions [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Corporate Equity Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Available for sale Securities, Fair Value