Fair Value - Assets and Liabilities Measured at Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	$ 542,198	$ 445,070
U.S. Treasury and Government Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	93,692	53,223
Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	9,529	3,748
Mutual Funds and Other Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	9,978	10,409
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	542,198	445,070
Fair Value, Measurements, Recurring [Member] | U.S. Treasury and Government Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	93,692	53,223
Fair Value, Measurements, Recurring [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	339,695	295,088
Fair Value, Measurements, Recurring [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	89,304	82,602
Fair Value, Measurements, Recurring [Member] | Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	9,529	3,748
Fair Value, Measurements, Recurring [Member] | Mutual Funds and Other Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	9,978	10,409
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	9,978	10,409
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Treasury and Government Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis
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, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mutual Funds and Other Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	9,978	10,409
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	532,220	431,711
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | U.S. Treasury and Government Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	93,692	53,223
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	339,695	295,088
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	89,304	82,602
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis	9,529	798
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Mutual Funds and Other Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis		2,950
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. Treasury and Government Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis		2,950
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mutual Funds and Other Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value measured on a recurring basis
Fair Value, Measurements, Non-recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis	1,275	22,872
Fair Value, Measurements, Non-recurring [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis		6,835
Fair Value, Measurements, Non-recurring [Member] | Construction [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis		3,219
Fair Value, Measurements, Non-recurring [Member] | Residential [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis	380	8,514
Fair Value, Measurements, Non-recurring [Member] | Commercial & Industrial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis	895	1,737
Fair Value, Measurements, Non-recurring [Member] | Loans Held for Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis		2,317
Fair Value, Measurements, Non-recurring [Member] | Other Real Estate Owned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis		250
Fair Value, Measurements, Non-recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Construction [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Residential [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Commercial & Industrial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Loans Held for Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Real Estate Owned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Construction [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Residential [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Commercial & Industrial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Loans Held for Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Other Real Estate Owned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis
Fair Value, Measurements, Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis	1,275	22,872
Fair Value, Measurements, Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis		6,835
Fair Value, Measurements, Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Construction [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis		3,219
Fair Value, Measurements, Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Residential [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis	380	8,514
Fair Value, Measurements, Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Commercial & Industrial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis	895	1,737
Fair Value, Measurements, Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Loans Held for Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis		2,317
Fair Value, Measurements, Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Other Real Estate Owned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans measured on a non-recurring basis		$ 250