EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net income (loss)	$ 26,996	$ 85,452	$ 82,558	$ 156,932
Denominator (shares in 000's):
Basic weighted average shares outstanding (in shares)	59,354,000	62,305,000	59,769,000	62,733,000
Effect of dilutive securities - Stock options and awards (in shares)	477,000	665,000	531,000	686,000
Diluted weighted average shares outstanding (in shares)	59,831,000	62,970,000	60,300,000	63,419,000
Earnings (loss) per share
Basic earnings per share (Note 3)	$ 0.45	$ 1.37	$ 1.38	$ 2.50
Diluted earnings per share (Note 3)	$ 0.45	$ 1.36	$ 1.37	$ 2.47
Anti-dilutive shares excluded from the computation of diluted earnings per share	852,159	548,049	779,404	346,168