Fair Value Measurements and Other Financial Instruments - Carrying Amounts and Estimated Fair Values of Debt (Detail) € in Millions, $ in Millions	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2015 EUR (€)	Dec. 31, 2014 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other foreign loans, Carrying Amount	$ 127.7			$ 73.9
Other foreign loans, Fair Value	127.8			73.8
Other domestic loans, Carrying Amount	159.2			59.2
Other domestic loans, Fair Value	159.5			59.2
Total debt, Carrying Amount	4,650.1			4,414.0
Total debt, Fair Value	4,700.8			4,569.4
6.50% Senior Notes Due December 2020 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes, Carrying Amount	427.8			428.1
Senior Notes, Fair Value	469.6			469.7
8.375% Senior Notes Due September 2021 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes, Carrying Amount				750.0
Senior Notes, Fair Value				843.3
4.875% Senior Notes due December 2022 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes, Carrying Amount	425.0			425.0
Senior Notes, Fair Value	420.1			423.3
5.25% Senior Notes Due April 2023 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes, Carrying Amount	425.0			425.0
Senior Notes, Fair Value	427.1			429.6
4.50% Senior Notes due September 2023 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes, Carrying Amount	449.9		€ 400
Senior Notes, Fair Value	456.0
5.125% Senior Notes due December 2024 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes, Carrying Amount	425.0			425.0
Senior Notes, Fair Value	418.3			428.5
5.50% Senior Notes due September 2025 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes, Carrying Amount	400.0	$ 400.0
Senior Notes, Fair Value	406.0
6.875% Senior Notes Due July 2033 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes, Carrying Amount	448.7			448.7
Senior Notes, Fair Value	454.7			462.9
Term Loan A Due July 2017 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Credit Facility, Carrying Amount	249.8			249.7
Credit Facility, Fair Value	249.7			249.7
Term Loan A Due July 2019 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Credit Facility, Carrying Amount	1,112.0			1,129.4
Credit Facility, Fair Value	$ 1,112.0			$ 1,129.4