EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net income	$ 16,930	$ 23,750	$ 39,469	$ 60,145
Denominator:
Denominator for basic earnings per share	26,130	26,323	26,158	26,339
Dilutive effect of unvested employee stock awards	181	156	179	157
Denominator for diluted earnings per share	26,311	26,479	26,337	26,496
Earnings per share:
Basic	$ 0.65	$ 0.90	$ 1.51	$ 2.28
Diluted	$ 0.64	$ 0.90	$ 1.50	$ 2.27
Additional Disclosure
Employee stock awards excluded from computation of diluted earnings per share	0	0	0	0