INCOME (LOSS) PER SHARE - Schedule of Weighted-Average Potentially Dilutive Instruments (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	6,716,581	6,407,194	6,259,285
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	1,887,322	1,652,002	1,527,601
Other stock-based compensation awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	199,629	125,562	102,054
Convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	2,314,815	2,314,815	2,314,815
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	2,314,815	2,314,815	2,314,815
Market-based Performance Share Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share-based compensation arrangement by share-based payment award, equity instruments other than options, nonvested, number (in shares)	57,668