Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation - Additional Information (Detail)

v3.5.0.2
Share-Based Compensation - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2016
Jun. 30, 2015
Jun. 30, 2016
Jun. 30, 2015
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Share-based compensation expense $ 10.7 $ 12.7 $ 20.5 $ 23.9  
Unrecognized compensation cost on non-vested stock awards 70.4   $ 70.4    
Unrecognized compensation cost on non-vested stock awards, weighted-average period of recognition     1 year 8 months 12 days    
Total intrinsic value of awards exercised for options and SARs 8.2 2.0 $ 14.1 19.6  
Total vesting date fair value of stock units 1.8 $ 1.0 1.8 $ 1.0  
Unrealized excess tax benefits $ 25.4   $ 25.4   $ 25.4
SARs [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Weighted-average grant date fair value of SARs granted $ 29.77 $ 19.46 $ 29.47 $ 12.81