Background and Basis of Presentation (Details 3) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	May 31, 2013
Senior notes | 2021 Senior Notes (5.25% fixed rate)
Fair Value of Financial Instruments
Fixed rate of interest (as a percent)	5.25%	5.25%	5.25%
Secured debt | Second German Loan Agreement (2.5% fixed rate)
Fair Value of Financial Instruments
Fixed rate of interest (as a percent)	2.50%
Carrying Value
Fair Value of Financial Instruments
Total Debt	223.2	234.3
Carrying Value | Senior notes | 2021 Senior Notes (5.25% fixed rate)
Fair Value of Financial Instruments
Total Debt	175.0	175.0
Carrying Value | Secured debt | Second German Loan Agreement (2.5% fixed rate)
Fair Value of Financial Instruments
Total Debt	9.1	10.6
Carrying Value | Secured debt | Global Revolving Credit Facilities (variable rates) due December 2019
Fair Value of Financial Instruments
Total Debt	39.1	48.7
Fair Value | Level 2
Fair Value of Financial Instruments
Total Debt	220.5	227.3
Fair Value | Level 2 | Senior notes | 2021 Senior Notes (5.25% fixed rate)
Fair Value of Financial Instruments
Total Debt	172.4	169.6
Fair Value | Level 2 | Secured debt | Second German Loan Agreement (2.5% fixed rate)
Fair Value of Financial Instruments
Total Debt	9.0	9.0
Fair Value | Level 2 | Secured debt | Global Revolving Credit Facilities (variable rates) due December 2019
Fair Value of Financial Instruments
Total Debt	39.1	48.7