REVENUE - Allowance for Doubtful Accounts (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2020	$ 4.9
Provision for doubtful accounts	0.0
Write-offs, net of recoveries and other	(0.1)
Balance at March 31, 2021	$ 4.8