Financial Instruments - Financial Instruments not Carried at Fair Value but which Require Fair Value Disclosure (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Carrying Amount
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Cash, cash equivalents and restricted cash	$ 169.9	$ 63.8
Term loan	345.9
Common stockholders' equity	781.1	935.1
Carrying Amount | North American Credit Facility
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Line of credit facility		11.1
Fair Value
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Cash, cash equivalents and restricted cash	169.9	63.8
Term loan	341.5
Common stockholders' equity	1,508.7	2,207.2
Fair Value | North American Credit Facility
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Line of credit facility		11.1
Contran | Carrying Amount
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Note payable to Contran		170.0
Contran | Fair Value
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Note payable to Contran		$ 170.0