Segment and Geographical Area Information (External Revenue and Long-Lived Assets) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	$ 605.1	$ 571.9	$ 1,187.0	$ 1,114.7
Long-lived assets	225.6		225.6		$ 218.9
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	431.6	410.3	856.1	801.2
Long-lived assets	184.3		184.3		189.5
Total International
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	173.5	161.6	330.9	313.5
Long-lived assets	41.3		41.3		29.4
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	48.2	42.0	91.9	80.9
Long-lived assets	5.7		5.7		6.1
Continental Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	55.0	50.1	105.6	99.8
Long-lived assets	6.5		6.5		5.3
Australia
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	16.2	15.7	31.3	30.7
Long-lived assets	1.5		1.5		1.6
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	38.6	37.8	71.7	70.4
Long-lived assets	17.6		17.6		6.6
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	12.2	13.0	24.1	25.7
Long-lived assets	9.8		9.8		9.6
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	3.3	$ 3.0	6.3	$ 6.0
Long-lived assets	$ 0.2		$ 0.2		$ 0.2