EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator:
Net income (loss)	$ 72,461	$ 70,539	$ 229,393	$ 200,227
Denominator (shares in 000's):
Basic weighted average shares outstanding (in shares)	61,380,000	64,821,000	62,282,000	65,245,000
Effect of dilutive securities - Stock options and awards (in shares)	681,000	831,000	690,000	810,000
Diluted weighted average shares outstanding (in shares)	62,061,000	65,652,000	62,972,000	66,055,000
Earnings (loss) per share
Basic earnings (loss) per share (in dollars per share)	$ 1.18	$ 1.09	$ 3.68	$ 3.07
Diluted earnings (loss) per share (in dollars per share)	$ 1.17	$ 1.07	$ 3.64	$ 3.03
Anti-dilutive shares excluded from the computation of diluted earnings per share	548,049	346,168	514,402	317,528