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Stock-Based Compensation - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Nov. 09, 2009
Compensation Related Costs Disclosure [Line Items]        
Common stock reserved for issuance (in shares)       11,815,748
Compensation expense $ 64.5 $ 69.5 $ 58.4  
Unrecognized compensation expense $ 56.7      
Unrecognized compensation expense, period of recognition 1 year 8 months 12 days      
Restricted Stock Units        
Compensation Related Costs Disclosure [Line Items]        
Weighted average grant date fair value of performance shares granted (in dollars per share) $ 104.46 $ 79.73 $ 56.69  
Performance Shares        
Compensation Related Costs Disclosure [Line Items]        
Vesting period 3 years      
Weighted average grant date fair value of performance shares granted (in dollars per share) $ 97.92 $ 73.85 $ 51.03