INCOME TAXES - Components of income tax expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Current tax expense:
U.S. federal	$ 627	$ 7,190	$ 7,440
State	1,505	2,316	379
Foreign	526	247	46
Total current tax expense	2,658	9,753	7,865
Deferred tax expense (benefit):
U.S. federal	12,911	3,298	8,915
State	1,304	(1,172)	(114)
Foreign	(49)	(27)	(8)
Total deferred tax expense	14,166	2,099	8,793
Total income tax expense	$ 16,824	$ 11,852	$ 16,658