FAIR VALUE OF FINANCIAL INSTRUMENTS - Narrative (Details) - Embedded Derivative Financial Instruments - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized loss on derivatives	$ 0.3	$ 58.3
ARM Sales Agreement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized loss on derivatives	3.2
Derivative liability, impact of 10 percent favorable change in discount rate	$ (2.5)