Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Additional Information (Detail)

v3.10.0.1
Income Taxes - Additional Information (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Income Tax Disclosure [Abstract]        
Income taxes (benefit) expense $ 48.4 $ 29.4 $ 57.8 $ 57.8
Effective income tax rate 33.90% 17.60% 24.70% 20.60%
Excess tax benefits on share-based compensation included in discrete events $ 10.9 $ 21.4 $ 30.2 $ 25.7
Total amount of unrecognized tax benefits, including related interest and penalties 65.0   65.0  
Unrecognized tax benefits excluding interest and penalties that if recognized would affect the effective tax rate 46.8   46.8  
Total accrued interest for tax contingencies 9.6   9.6  
Total accrued penalties for tax contingencies 1.6   1.6  
Amount of unrecognized tax benefits that could decrease within the next 12 months 8.6   8.6  
Decrease in unrecognized tax benefits due to the settlement of audits or resolution of administrative or judicial proceedings 0.4   0.4  
Decrease in unrecognized tax benefits expiration of statute of limitations $ 8.2   $ 8.2  
Effective tax rate applied     21.00%