Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Schedule of Long-Term Debt (Detail)

v3.8.0.1
Long-Term Debt - Schedule of Long-Term Debt (Detail) - USD ($)
$ in Millions
Mar. 31, 2018
Dec. 31, 2017
Feb. 28, 2014
Debt Instrument [Line Items]      
Other $ 7.7 $ 7.9  
Total 2,211.4 2,268.1  
Less: current portion 102.3 102.4  
Long-term portion 2,109.1 2,165.7  
2.000% Convertible Senior Notes Due 2019 [Member]      
Debt Instrument [Line Items]      
Convertible senior notes, carrying value of liability component 635.0 1,070.0  
Total     $ 930.9
2.625% Convertible Senior Notes Due 2024 [Member]      
Debt Instrument [Line Items]      
Convertible senior notes, carrying value of liability component 401.0    
Total 410.1    
Senior Secured Credit Facility [Member]      
Debt Instrument [Line Items]      
Borrowings under senior secured credit facility, carrying value $ 1,167.7 $ 1,190.2