EARNINGS PER SHARE - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Reconciliation of shares for basic and diluted net income per share
Net income	$ 21,302	$ 17,030	$ 45,692	$ 32,594
Weighted average common shares outstanding—basic (in shares)	85,285	81,147	84,686	81,238
Effect of dilutive securities (in shares)	1,088	1,777	1,466	1,708
Weighted average common shares outstanding—diluted (in shares)	86,373	82,924	86,152	82,946
Earnings per share
Basic (in dollars per share)	$ 0.25	$ 0.21	$ 0.54	$ 0.40
Diluted (in dollars per share)	$ 0.25	$ 0.21	$ 0.53	$ 0.39