Segment and Geographical Area Information (External Revenue and Long-Lived Assets) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	$ 617.4	$ 569.4	$ 1,804.4	$ 1,684.1
Long-lived assets	225.9		225.9		$ 218.9
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	440.7	411.3	1,296.8	1,212.5
Long-lived assets	183.3		183.3		189.5
Total International
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	176.7	158.1	507.6	471.6
Long-lived assets	42.6		42.6		29.4
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	48.2	42.1	140.1	123.0
Long-lived assets	5.0		5.0		6.1
Continental Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	55.1	51.6	160.7	151.4
Long-lived assets	6.3		6.3		5.3
Australia
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	16.7	16.3	48.0	47.0
Long-lived assets	1.3		1.3		1.6
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	41.0	33.0	112.7	103.4
Long-lived assets	17.4		17.4		6.6
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	12.4	11.9	36.5	37.6
Long-lived assets	12.4		12.4		9.6
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
External revenue	3.3	$ 3.2	9.6	$ 9.2
Long-lived assets	$ 0.2		$ 0.2		$ 0.2