Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation - Additional Information (Detail)

v2.4.0.8
Share-Based Compensation - Additional Information (Detail) (USD $)
In Millions, except Per Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2014
Mar. 31, 2013
Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]      
Share-based compensation expense $ 11.0 $ 7.9  
Unrecognized compensation cost on non-vested stock awards 47.5    
Unrecognized compensation cost on non-vested stock awards, weighted-average period of recognition 1 year 4 months 24 days    
Weighted-average grant date fair value of SARs granted $ 28.68 $ 11.15  
Total intrinsic value of awards exercised for options and SARs 14.8 0.3  
Total vesting date fair value of stock units 8.2 4.3  
Unrealized excess tax benefits $ 16.5   $ 15.4