FINANCING ARRANGEMENTS - Schedule of Convertible Debt Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Contractual interest (3.25% of the principal amount per annum)	$ 8,128	$ 8,128	$ 8,128
Amortization of debt discount	13,200	11,916	10,758
Total	$ 21,328	$ 20,044	$ 18,886