NET INCOME (LOSS) PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Earnings Per Share [Abstract]
Net income	$ 19,406	$ 17,732	$ 27,682	$ 26,487
Weighted average number of common shares used in basic net income per common share	39,163	40,227	39,264	40,335
Dilutive effect of non-vested restricted stock	391	242	355	241
Weighted average number of common shares used in diluted net income per common share	39,554	40,469	39,619	40,576
Net income per common share:
Basic (in dollars per share)	$ 0.50	$ 0.44	$ 0.71	$ 0.66
Diluted (in dollars per share)	$ 0.49	$ 0.44	$ 0.70	$ 0.65
Anti-dilutive shares	246	254	336	218