FAIR VALUE MEASUREMENTS - Schedule of Assets and Liabilities at Fair Value on Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents, and restricted cash	$ 157.7	$ 131.9
Marketable securities	162.2	191.5
EVE Investment	15.4	18.7
U.S. Treasury Warrants		(6.8)
Total	335.3
Total		335.3
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents, and restricted cash	157.7	131.9
Marketable securities	162.2	191.5
EVE Investment	4.0	5.4
U.S. Treasury Warrants		0.0
Total	323.9
Total		328.8
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents, and restricted cash	0.0	0.0
Marketable securities	0.0	0.0
EVE Investment	0.0	0.0
U.S. Treasury Warrants		0.0
Total	0.0
Total		0.0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash, cash equivalents, and restricted cash	0.0	0.0
Marketable securities	0.0	0.0
EVE Investment	11.4	13.3
U.S. Treasury Warrants		(6.8)
Total	$ 11.4
Total		$ 6.5