Segment and Geographical Area Information (External Revenue and Long-Lived Assets) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	$ 324.0	$ 258.9
Long-lived assets	149.5		$ 154.7
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	234.6	195.1
Long-lived assets	127.7		131.2
Total International
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	89.4	63.8
Long-lived assets	21.8		23.5
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	26.0	18.1
Long-lived assets	6.6		6.9
Continental Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	23.0	20.4
Long-lived assets	2.4		2.3
Australia
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	10.6	9.5
Long-lived assets	3.5		4.2
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	20.7	7.9
Long-lived assets	2.5		2.9
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	7.6	6.3
Long-lived assets	6.4		6.6
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	1.5	$ 1.6
Long-lived assets	$ 0.4		$ 0.6