SEGMENT REPORTING - Long-lived assets by geographic areas (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Segment Reporting Information
Revenues less cost of revenues	$ 728.9	$ 565.2
Long-lived assets	242.5		$ 244.1
United States
Segment Reporting Information
Revenues less cost of revenues	633.8	492.1
Long-lived assets	188.8		184.5
United Kingdom
Segment Reporting Information
Long-lived assets	26.2		30.0
Other
Segment Reporting Information
Revenues less cost of revenues	95.1	$ 73.1
Long-lived assets	$ 27.5		$ 29.6