Segment Information - Long-lived Assets by Geographic Area (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant & equipment, net	$ 452.3	$ 460.5
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant & equipment, net	122.2	137.4
France
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant & equipment, net	48.2	47.2
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant & equipment, net	42.0	47.3
Other countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant & equipment, net	$ 239.9	$ 228.6