NET INCOME (LOSS) PER SHARE - Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Basic net income (loss) per share:
Net income (loss)	$ 32,337	$ (369)	$ 9,180	$ (27,610)	$ 29,736	$ 32,756	$ 41,148	$ 34,882
Weighted average common shares outstanding - Basic (in shares)	84,325			85,688			84,745	85,536
Basic net income (loss) per common share (in dollars per share)	$ 0.38			$ (0.32)			$ 0.49	$ 0.41
Diluted net income (loss) per share:
Net income (loss)	$ 32,337	$ (369)	$ 9,180	$ (27,610)	$ 29,736	$ 32,756	$ 41,148	$ 34,882
Weighted average common shares outstanding - Basic (in shares)	84,325			85,688			84,745	85,536
Effect of dilutive securities:
Stock options and restricted stock (in shares)	427			0			558	1,045
Weighted average common shares for diluted earnings per share (in shares)	84,752			85,688			85,303	86,581
Diluted net income (loss) per common share (in dollars per share)	$ 0.38			$ (0.32)			$ 0.48	$ 0.40