Debt and Credit Facilities - Additional Information (Detail) € in Millions, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2015 EUR (€)	Dec. 31, 2014 USD ($)
Debt Instrument [Line Items]
Loss on debt redemption and refinancing activities	$ 0.6		$ (17.7)	$ (110.7)	$ (18.5)
5.50% Senior Notes due September 2025 [Member]
Debt Instrument [Line Items]
Credit facility, maturity date		Sep. 15, 2025
Senior Notes	$ 400.0	$ 400.0		$ 400.0
Debt interest rate	5.50%	5.50%		5.50%		5.50%	5.50%
Senior notes fees		$ 8.0
4.50% Senior Notes due September 2023 [Member]
Debt Instrument [Line Items]
Credit facility, maturity date		Sep. 15, 2023
Senior Notes	$ 449.9			$ 449.9		€ 400
Debt interest rate	4.50%	4.50%		4.50%		4.50%	4.50%
Senior notes fees		$ 8.0
8.375% Senior Notes Due September 2021 [Member]
Debt Instrument [Line Items]
Credit facility, maturity date		Sep. 01, 2021
Senior Notes							$ 750.0
Debt interest rate	8.375%	8.375%		8.375%		8.375%	8.375%
Aggregate repurchase price of senior notes		$ 866.0
Repurchased debt principal amount		750.0
Premium paid on redemption of debt		99.0
Accrued interest paid on redemption of debt		17.0
Loss on debt redemption and refinancing activities		111.0
Amortization Of Debt Discount Premium		$ 11.0