COMMITMENTS AND CONTINGENCIES - Litigation (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Mar. 31, 2018
Income Tax Examination [Line Items]
Gross receipts tax and payroll expense tax paid	$ 8,400,000	$ 1,300,000
Minimum
Income Tax Examination [Line Items]
Estimate of possible liability for additional taxes, interest and penalties	0
Maximum
Income Tax Examination [Line Items]
Estimate of possible liability for additional taxes, interest and penalties	$ 63,000,000