EARNINGS PER SHARE - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator for basic and diluted earnings per share:
Net income	$ 29,023	$ 11,572	$ 36,244	$ 976	$ 40,595	$ 37,220
Denominator:
Basic shares outstanding (in shares)	55,590		55,875		55,673	55,861
Dilutive effect of outstanding stock awards (in shares)	158		191		209	140
Dilutive shares outstanding (in shares)	55,748		56,066		55,882	56,001
Basic earnings per share (in USD per share)	$ 0.52		$ 0.65		$ 0.73	$ 0.67
Diluted earnings per share (in USD per share)	$ 0.52		$ 0.65		$ 0.73	$ 0.66