NET INCOME (LOSS) PER SHARE - Schedule of Earnings (Loss) Per Share and Dilutive Shares Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Basic net income (loss) per share
Net income (loss)	$ 41,230	$ (14,301)
Weighted average common shares outstanding (in shares)	70,940	64,239
Basic net (loss) income per share (in dollars per share)	$ 0.58	$ (0.22)
Diluted net income (loss) per share
Add: effect of dilutive stock options, awards, and equivalents (in shares)	111	0
Denominator for diluted income (loss) per share (in shares)	71,051	64,239
Diluted net (loss) income per share (in dollars per share)	$ 0.58	$ (0.22)
Potentially dilutive common shares:
Total potentially dilutive common shares (in shares)	38,503	24,034
Convertible debt | 2.5% Convertible Notes debt 2021
Potentially dilutive common shares:
Total potentially dilutive common shares (in shares)	5,111	17,931
Convertible debt | 5.0% Convertible Notes debt 2024
Potentially dilutive common shares:
Total potentially dilutive common shares (in shares)	26,248	0
Stock options, awards and equivalents
Potentially dilutive common shares:
Total potentially dilutive common shares (in shares)	7,144	6,103