EARNINGS PER SHARE (Computation of Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator for basic and diluted earnings per share:
Net income	$ 31,089	$ 12,058	$ 49,205	$ 16,545
Denominator:
Basic shares outstanding (in shares)	56,059	57,033	56,222	57,149
Dilutive effect of equity-based compensation awards (in shares)	232	162	138	131
Dilutive shares outstanding (in shares)	56,291	57,195	56,360	57,280
Basic income per share (in USD per share)	$ 0.55	$ 0.21	$ 0.88	$ 0.29
Diluted income per share (in USD per share)	$ 0.55	$ 0.21	$ 0.87	$ 0.29