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SHARE-BASED COMPENSATION - Narrative (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 7.5	$ 0.8	$ 14.7	$ 27.0
Restricted stock unit expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	6.1	0.0	10.9	0.0
Unrecognized compensation cost	81.7		$ 81.7
Unrecognized compensation cost, period of recognition			4 years
Stock option expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	1.4	$ 0.8	$ 3.8	27.0
Unrecognized compensation cost	$ 5.7		$ 5.7
Unrecognized compensation cost, period of recognition			5 years
Tender offer \| Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense				$ 25.1
2020 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance (in shares)	22.2		22.2