Quarterly report pursuant to Section 13 or 15(d)

Earnings Per Share - Additional Information (Detail)

v2.4.0.6
Earnings Per Share - Additional Information (Detail) (Stock Option Awards [Member])
3 Months Ended 9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Stock Option Awards [Member]
       
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Anti-dilutive shares 80,825 390,150 122,525 390,150