v2.4.0.6
Fair Value - Additional Information (Detail) (USD $)
6 Months Ended 9 Months Ended
Dec. 31, 2011
Sep. 30, 2012
Sep. 30, 2011
Fair Value Measurements [Line Items]      
Impaired loans gross carrying amount $ 29,124,000 $ 24,746,000  
Impaired loans, valuation allowance 7,443,000 6,254,000 7,762,000
Increase in provision for loan losses $ 1,699,000 $ 1,189,000