v2.4.0.6
Fair Value - Additional Information (Detail) (USD $)
6 Months Ended
Jun. 30, 2012
Dec. 31, 2011
Jun. 30, 2011
Fair Value Measurements [Line Items]   
Impaired loans gross carrying amount$ 31,686,000$ 29,124,000 
Impaired loans, valuation allowance7,516,0007,443,0007,666,000
Increase in provision for loan losses$ 73,000$ 1,699,000 
Minimum
   
Fair Value Measurements [Line Items]   
Loans classified as Level 3, other unobservable inputs additional discounts5.00%  
Maximum
   
Fair Value Measurements [Line Items]   
Loans classified as Level 3, other unobservable inputs additional discounts10.00%