Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	$ 410,210	$ 381,862
Stock Warrants	1,060	883
Total Debt Securities Available For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	409,919	381,181
Financial Services Industry [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	291	681
Total Equity Securities Available For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	291	681
Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	142,168	113,005
Collateralized Mortgage Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	101,390	162,837
U.S. Government Agencies Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	79,164	72,548
Municipal Bonds-Tax Exempt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	12,738	3,482
Municipal Bonds-Taxable [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	46,234	6,138
Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	19,897	19,836
Other Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	8,328	3,335
Quoted Prices in Active Markets for Identical Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	79,455	73,229
Quoted Prices in Active Markets for Identical Assets [Member] | Total Debt Securities Available For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	79,164	72,548
Quoted Prices in Active Markets for Identical Assets [Member] | Financial Services Industry [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	291	681
Quoted Prices in Active Markets for Identical Assets [Member] | Total Equity Securities Available For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	291	681
Quoted Prices in Active Markets for Identical Assets [Member] | U.S. Government Agencies Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	79,164	72,548
Significant Observable Inputs With No Active Market With Identical Characteristics [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	329,967	308,633
Significant Observable Inputs With No Active Market With Identical Characteristics [Member] | Total Debt Securities Available For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	329,967	308,633
Significant Observable Inputs With No Active Market With Identical Characteristics [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	142,168	113,005
Significant Observable Inputs With No Active Market With Identical Characteristics [Member] | Collateralized Mortgage Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	101,390	162,837
Significant Observable Inputs With No Active Market With Identical Characteristics [Member] | Municipal Bonds-Tax Exempt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	11,950	3,482
Significant Observable Inputs With No Active Market With Identical Characteristics [Member] | Municipal Bonds-Taxable [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	46,234	6,138
Significant Observable Inputs With No Active Market With Identical Characteristics [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	19,897	19,836
Significant Observable Inputs With No Active Market With Identical Characteristics [Member] | Other Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	8,328	3,335
Significant Unobservable Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	788
Stock Warrants	1,060	883
Significant Unobservable Inputs [Member] | Total Debt Securities Available For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	788
Significant Unobservable Inputs [Member] | Municipal Bonds-Tax Exempt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Securities Available for Sales	$ 788