Quarterly report pursuant to Section 13 or 15(d)

Accounting for Uncertainty in Income Taxes - Additional Information (Detail)

v2.4.0.6
Accounting for Uncertainty in Income Taxes - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
9 Months Ended 12 Months Ended
Sep. 30, 2012
Dec. 31, 2011
Sep. 30, 2011
Income Taxes [Line Items]      
Liability for unrecognized tax $ 12.0   $ 15.4
Unrecognized tax favorable impact on effective tax rate 5.2   8.5
Accrued interest and penalties applied to uncertain tax positions $ 7.0 $ 8.4