Annual report pursuant to Section 13 and 15(d)

Shareholders' Deficit - Additional Information (Detail)

v3.20.4
Shareholders' Deficit - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
 1 Months Ended 3 Months Ended 12 Months Ended
Dec. 31, 2020
Aug. 31, 2020
Oct. 30, 2018
May 31, 2018
Feb. 28, 2014
Mar. 31, 2014
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Nov. 04, 2020
Oct. 31, 2017
Stockholders Equity [Line Items]                      
Exercise price of common stock                   $ 67.50  
Common shares, shares outstanding 120,100,000           120,100,000 137,400,000 142,800,000    
Preference shares authorized 7,500,000           7,500,000        
Preference shares par value $ 0.002           $ 0.002        
Share repurchase program authorized amount $ 1,500.0   $ 1,500.0       $ 1,500.0        
Share repurchase program, remaining authorized capacity 607.9   $ 113.3       $ 607.9        
Share repurchase program expiration date     Feb. 21, 2020       Oct. 30, 2023        
Forward counterparties shares purchased and subsequently retired               6,000,000.0 13,900,000    
Accumulated deficit $ (687.4)           $ (687.4) $ (215.3)      
Repurchase of common stock, shares             19,000,000.0 400,000 14,300,000    
Treasury stock shares, at cost 10,000,000.0           10,000,000.0 10,000,000.0      
Shares repurchases, inclusive of transaction costs and issuance of CVR value             $ 893.9 $ 0.0 $ 600.7    
Withheld for tax purpose for share-based compensation plans             29.6 16.7 145.4    
Shares repurchases, value             923.5 16.7 746.1    
Share repurchases             923.5 16.7 750.3    
Payments for share repurchases from prior period liability                 4.2    
Terminating result of portion of capped call transactions cash received                 55.9    
Other comprehensive loss before unrealized gain (loss) on derivatives adjustments reclassifications, tax expense (benefit)             (0.6)        
Other comprehensive income (loss) before foreign currency translation adjustments reclassifications, tax expense (benefit)             (2.0) $ (0.1) $ 2.7    
Other comprehensive income (Loss), reclassification adjustment from AOCI on derivatives, net of tax expense (benefit)             0.2        
Capped call transactions [Member]                      
Stockholders Equity [Line Items]                      
Capped call transactions with financial institutions         $ 123.8            
Capped call transactions price per common share         $ 60.39            
Increase (decrease) in additional paid-in capital, other           $ (123.8)          
Terminating result of portion of capped call transactions cash received             $ 55.9        
Capped call transactions [Member] | Convertible Senior Notes Due 2019 [Member]                      
Stockholders Equity [Line Items]                      
Convertible notes conversion price         $ 43.14            
Open market purchases [Member]                      
Stockholders Equity [Line Items]                      
Repurchase of common stock, shares             3,000,000.0        
Shares repurchases, value             $ 142.1        
Average cost per share of shares repurchased             $ 47.40        
Open market purchases [Member] | Indirect wholly owned subsidiary [Member]                      
Stockholders Equity [Line Items]                      
Average cost per share of shares repurchased                 $ 33.90    
Repurchase of common stock, shares                 8,400    
Repurchase of common stock, value                 $ 0.3    
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         19,900,000            
Average cost per share of shares repurchased         $ 34.51            
Settlement date of forward transactions               Aug. 15, 2019      
Forward counterparties shares purchased and subsequently retired 19,900,000             6,000,000.0 13,900,000    
Shares outstanding under forward purchasing transactions 0           0        
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               $ 1.2 $ 9.2    
August 2020 Dutch Auction Tender Offer [Member]                      
Stockholders Equity [Line Items]                      
Average cost per share of shares repurchased   $ 48.75                  
Repurchase of common stock, shares   15,400,000                  
Repurchase of common stock, value   $ 750.0                  
May 2018 Dutch Auction Tender Offer [Member]                      
Stockholders Equity [Line Items]                      
Average cost per share of shares repurchased       $ 52.50              
Repurchase of common stock, shares       11,400,000              
Repurchase of common stock, value       $ 600.0              
October 2017 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        
Gain (loss) recognized in other expense             $ 0.0 $ 15.7 $ (8.8)