Business Segments - Long-lived Assets by Geographic Location (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 259.8	$ 251.2	$ 224.5
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	166.0	161.6	154.1
Brazil
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	12.8	13.9	12.6
All other countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 81.0	$ 75.7	$ 57.8