LONG-TERM DEBT - Schedule of Carrying Values and Estimated Fair Values of Convertible Notes (Details) - 1.25% Convertible Senior Notes, Due December 2026 - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Debt Instrument, Redemption [Line Items]
Principal Amount	$ 2,012.5	$ 2,012.5
Unamortized Debt Discounts and Issuance Costs	24.5	25.7
Convertible Debt, Total	1,988.0	1,986.8
Level 2
Debt Instrument, Redemption [Line Items]
Fair Value (Level 2)	$ 1,528.2	$ 1,984.6