NET INCOME PER SHARE - Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Basic net income per share:
Net income	$ 29,736	$ 32,756	$ 11,376	$ 10,992	$ 62,492	$ 22,368
Weighted average common shares outstanding - Basic (in shares)	85,577		82,423		85,460	80,491
Basic net income per common share (in dollars per share)	$ 0.35		$ 0.14		$ 0.73	$ 0.28
Diluted net income per share:
Net income	$ 29,736	$ 32,756	$ 11,376	$ 10,992	$ 62,492	$ 22,368
Weighted average common shares outstanding - Basic (in shares)	85,577		82,423		85,460	80,491
Effect of dilutive securities:
Stock options and restricted stock (in shares)	680		1,090		947	1,211
Weighted average common shares for diluted earnings per share (in shares)	86,257		83,513		86,407	81,702
Diluted net income per common share (in dollars per share)	$ 0.34		$ 0.14		$ 0.72	$ 0.27