INCOME (LOSS) PER SHARE - Schedule of Weighted-Average Potentially Dilutive Instruments (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	105,071,010	99,829,018	125,738,830	123,799,669
Performance Shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares issuable upon vesting of outstanding performance share units (in shares)	5,326,725	1,179,984
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)	12,462,410	7,220,418	31,072,428	27,801,509
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)	16,000	16,000	2,073,802	3,405,560
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)	46,296,300	46,296,300	46,296,300	46,296,300
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	46,296,300	46,296,300	46,296,300	46,296,300