Fair Value Measurements and Other Financial Instruments - Carrying Amounts and Estimated Fair Values of Debt (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
6.50% Senior Notes due December 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	6.50%
4.875% Senior Notes due December 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	4.875%
5.25% Senior Notes due April 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	5.25%
4.50% Senior Notes due September 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	4.50%
5.125% Senior Notes due December 2024
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	5.125%
5.50% Senior Notes due September 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	5.50%
6.875% Senior Notes due July 2033
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	6.875%
Carrying Amount
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other foreign loans	$ 162.3	$ 30.2
Other domestic loans	1.3	3.6
Total debt	3,405.2	3,258.0
Carrying Amount | 6.50% Senior Notes due December 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	423.7	423.6
Carrying Amount | 4.875% Senior Notes due December 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	420.6	420.4
Carrying Amount | 5.25% Senior Notes due April 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	420.6	420.4
Carrying Amount | 4.50% Senior Notes due September 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	488.7	474.3
Carrying Amount | 5.125% Senior Notes due December 2024
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	420.9	420.7
Carrying Amount | 5.50% Senior Notes due September 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	396.7	396.7
Carrying Amount | 6.875% Senior Notes due July 2033
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	445.4	445.4
Carrying Amount | Term Loan A Facility due July 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Term Loan A Facility	225.0	222.7
Fair Value
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other foreign loans	161.3	30.4
Other domestic loans	1.4	3.6
Total debt	3,618.0	3,596.2
Fair Value | 6.50% Senior Notes due December 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	452.7	465.1
Fair Value | 4.875% Senior Notes due December 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	431.8	451.0
Fair Value | 5.25% Senior Notes due April 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	437.9	455.6
Fair Value | 4.50% Senior Notes due September 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	549.4	544.4
Fair Value | 5.125% Senior Notes due December 2024
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	434.4	456.2
Fair Value | 5.50% Senior Notes due September 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	417.9	439.9
Fair Value | 6.875% Senior Notes due July 2033
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	506.2	527.3
Fair Value | Term Loan A Facility due July 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Term Loan A Facility	$ 225.0	$ 222.7