EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Earning per share
Authorized common stock (in shares)	199,000		199,000		199,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01
Income (Numerator)
Income available to common stockholders, basic (in dollars)	$ 56,750	$ 38,996	$ 193,669	$ 154,071
Income available to common stockholders, diluted (in dollars)	$ 56,750	$ 38,996	$ 193,669	$ 154,071
Shares (Denominator)
Basic (in shares)	64,010	62,378	63,485	62,304
Total average equivalent shares	66,702	65,129	66,163	64,822
Per Share Amount
Net income per share, basic (in dollars per share)	$ 0.89	$ 0.63	$ 3.05	$ 2.47
Net income per share, diluted (in dollars per share)	$ 0.85	$ 0.60	$ 2.93	$ 2.38
Stock options
Shares (Denominator)
Effect of dilutive stock based compensation (in shares)	2,367	2,659	2,425	2,440
Restricted stock units
Shares (Denominator)
Effect of dilutive stock based compensation (in shares)	325	92	253	78