EARNINGS (LOSS) PER SHARE - Schedule of Basic and Diluted Earnings (Loss) per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator:
Net income (loss)	$ 22.8	$ (45.8)	$ 8.8	$ (123.4)
Less: Undistributed income allocated to participating securities	(1.1)	0.0	(0.5)	0.0
Net income (loss) attributable to common shareholders	$ 21.7	$ (45.8)	$ 8.3	$ (123.4)
Denominator:
Weighted-average common shares outstanding: basic (both Class A and B) (in shares)	15.0	14.5	14.8	14.4
Effect of dilutive securities:
Redeemable convertible preferred stock (in shares)	0.8	0.0	0.8	0.0
Weighted-average common shares outstanding: diluted (both Class A and B) (in shares)	16.9	14.5	16.8	14.4
Earnings (loss) per common share (both Class A and B):
Basic (in usd per share)	$ 1.45	$ (3.16)	$ 0.56	$ (8.57)
Diluted (in usd per share)	$ 1.35	$ (3.16)	$ 0.52	$ (8.57)
RSUs and PSUs
Effect of dilutive securities:
RSUs, PSUs and Stock options (in shares)	1.0	0.0	1.1	0.0
Stock options
Effect of dilutive securities:
RSUs, PSUs and Stock options (in shares)	0.1	0.0	0.1	0.0