DEBT - Interest expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Components of interest expense:
Contractual interest	$ 12.2	$ 14.8	$ 36.8	$ 47.3
Amortization of debt discount and issuance costs	0.6	0.6	1.8	1.9
Interest expense	12.8	15.4	38.6	49.2
Interest income	(11.4)	(3.5)	(20.1)	(8.3)
Interest expense, net	$ 1.4	$ 11.9	$ 18.5	$ 40.9