DEBT - Summary of Interest Expense of Senior Notes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Amortization of debt discount and debt issuance costs	$ 23,764	$ 21,877	$ 19,415
Senior Notes
Debt Instrument [Line Items]
Contractual interest expense	25,559	38,242	44,212
Amortization of debt discount and debt issuance costs	5,783	3,589	2,631
Total interest expense	$ 31,342	$ 41,831	$ 46,843