Quarterly report pursuant to Section 13 or 15(d)

Shareholders' Deficit - Summary of Changes in Shareholders' Deficit (Detail)

v3.10.0.1
Shareholders' Deficit - Summary of Changes in Shareholders' Deficit (Detail) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Beginning balance     $ (334.7)  
Net income $ 71.2 $ 54.5 247.7 $ 277.3
Additional paid-in capital from share-based compensation     31.8  
Repurchases of common shares     (736.4) (346.2)
Foreign currency translation adjustment (4.6) $ 11.3 (34.2) $ 41.0
Increase in additional paid-in capital due to partial unwind of Capped Call Transactions     55.9  
Other     (4.9)  
Ending balance $ (761.1)   (761.1)  
2024 Convertible Notes [Member]        
Increase in additional paid-in capital due to issuance of Convertible Notes     136.7  
2019 Convertible Notes [Member]        
Decrease in additional paid-in capital due to repurchase of Convertible Notes     $ (123.0)