Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Additional Information (Detail)

v2.4.0.6
Income Taxes - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
3 Months Ended 9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Income Taxes [Line Items]        
Gross unrecognized tax benefit balance, change within the next twelve months, lower limit $ 0   $ 0  
Gross unrecognized tax benefit balance, change within the next twelve months, upper limit $ 0 $ 9.1 $ 0 $ 9.1
Effective income tax rate 33.50% 36.20% 35.10% 43.90%
Boa Vista Servicos S.A. [Member]
       
Income Taxes [Line Items]        
Increase in effective income tax rate   23.20%   7.70%