Quarterly report pursuant to Section 13 or 15(d)

Shareholders' Deficit - Additional Information (Detail)

v3.8.0.1
Shareholders' Deficit - Additional Information (Detail)
$ / shares in Units, $ in Millions
 1 Months Ended 3 Months Ended 12 Months Ended
Apr. 18, 2018
Apr. 30, 2018
USD ($)
Mar. 31, 2018
USD ($)
$ / shares
shares
Feb. 28, 2014
USD ($)
$ / shares
shares
Mar. 31, 2018
USD ($)
$ / shares
shares
Mar. 31, 2017
USD ($)
$ / shares
shares
Mar. 31, 2014
USD ($)
Dec. 31, 2017
USD ($)
shares
Dec. 31, 2016
USD ($)
Oct. 31, 2017
USD ($)
Sep. 30, 2017
USD ($)
Feb. 21, 2017
USD ($)
Stockholders Equity [Line Items]                        
Share repurchase program authorized amount     $ 1,500.0   $ 1,500.0             $ 1,500.0
Share repurchase program, remaining authorized capacity                 $ 233.0   $ 713.3  
Share repurchase program expiration date         Feb. 21, 2020       Jun. 30, 2017      
Forward transactions, shares to be purchased | shares         9.9              
Accumulated deficit     $ (168.3)   $ (168.3)     $ (248.1)        
Repurchase of common stock, value         $ 50.0 $ 68.2            
Treasury stock shares, at cost | shares     5,000,000   5,000,000     5,000,000        
Shares repurchases, value         $ 0.3 60.7   $ 4.2        
Withheld for tax purpose for share-based compensation plans         49.7 7.5            
Payments for share repurchases         54.2 58.1            
Share repurchases for which subsequent payment to be made           10.1            
Terminating result of portion of capped call transactions cash received         27.1              
Other comprehensive income (loss) before foreign currency translation adjustments reclassifications, Tax expense         1.1 2.6            
Capped call transactions [Member]                        
Stockholders Equity [Line Items]                        
Capped call transactions with financial institutions       $ 123.8                
Capped call transactions price per common share | $ / shares       $ 120.79                
Increase (decrease) in additional paid-in capital, other     $ 44.0       $ (123.8)          
Terminating result of portion of capped call transactions cash received     27.1                  
Capped call transactions [Member] | Subsequent Event                        
Stockholders Equity [Line Items]                        
Increase (decrease) in additional paid-in capital, other   $ 12.0                    
Terminating result of portion of capped call transactions cash received   $ 16.9                    
Capped call transactions [Member] | Other current assets [Member]                        
Stockholders Equity [Line Items]                        
Terminating result of portion of capped call transactions recognized in other current assets     $ 16.9   $ 16.9              
Capped call transactions [Member] | Common Share [Member]                        
Stockholders Equity [Line Items]                        
Average adjusted cap price per common share | $ / shares     110   110              
Capped call transactions [Member] | Convertible Senior Notes Due 2019 [Member]                        
Stockholders Equity [Line Items]                        
Convertible notes initial conversion price | $ / shares       $ 86.28                
Prepaid forward share repurchase transactions [Member]                        
Stockholders Equity [Line Items]                        
Forward share repurchase transactions amount       $ 685.8     685.8          
Forward transactions, shares to be purchased | shares       9,900,000                
Average cost per share of shares repurchased | $ / shares       $ 69.02                
Settlement date of forward transactions         Aug. 15, 2019              
Accumulated deficit             (653.9)          
Additional paid-in-capital             (31.9)          
Non-cash forward transaction issuance costs             $ 35.8          
Non-cash interest expense relating to amortization of non-cash issuance costs         $ 1.6 $ 1.6            
Open market purchases [Member] | Indirect wholly owned subsidiary [Member]                        
Stockholders Equity [Line Items]                        
Average cost per share of shares repurchased | $ / shares         $ 67.79 $ 56.10            
Repurchase of common stock, shares | shares         4,200 1,100,000            
Repurchase of common stock, value         $ 0.3 $ 60.7            
Dutch Auction Tender Offer [Member]                        
Stockholders Equity [Line Items]                        
Forward share repurchase transactions amount         $ 1.6              
Contingent value right agreement term         2 years              
Non-transferable contractual contingent value right agreement initial fair value                   $ 7.3    
CVR expiration period         2019-08              
Loss recognized in other expense         $ 11.3              
Non-transferable contractual contingent value right agreement change in fair value     $ 18.2   $ 18.2     $ 6.9        
Dutch Auction Tender Offer [Member] | Subsequent Event                        
Stockholders Equity [Line Items]                        
Share repurchase program expiration date May 24, 2018