Background and Basis of Presentation - Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Senior notes | 2021 Senior Notes (5.25% fixed rate)
Fair Value of Financial Instruments
Fixed rate of interest (as a percent)	5.25%
Secured debt | German loan agreement (2.45% fixed rate)
Fair Value of Financial Instruments
Fixed rate of interest (as a percent)	2.45%
Carrying Value
Fair Value of Financial Instruments
Total debt	$ 272.8	$ 258.3
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 | Global Revolving Credit Facilities (variable rates)
Fair Value of Financial Instruments
Total debt	91.5	76.9
Carrying Value | Secured debt | German loan agreement (2.45% fixed rate)
Fair Value of Financial Instruments
Total debt	6.3	6.4
Level 2 | Fair Value
Fair Value of Financial Instruments
Total debt	266.0	253.5
Level 2 | Fair Value | Senior notes | 2021 Senior Notes (5.25% fixed rate)
Fair Value of Financial Instruments
Total debt	168.2	170.2
Level 2 | Fair Value | Secured debt | Global Revolving Credit Facilities (variable rates)
Fair Value of Financial Instruments
Total debt	91.5	76.9
Level 2 | Fair Value | Secured debt | German loan agreement (2.45% fixed rate)
Fair Value of Financial Instruments
Total debt	$ 6.3	$ 6.4