INCOME TAXES - Components of income tax expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 02, 2021	Dec. 28, 2019	Dec. 29, 2018
Current tax expense:
U.S. federal	$ 41,884	$ 627	$ 7,190
State	10,619	1,505	2,316
Foreign	829	526	247
Total current tax expense	53,332	2,658	9,753
Deferred tax expense (benefit):
U.S. federal	(3,332)	12,911	3,298
State	(538)	1,304	(1,172)
Foreign	(62)	(49)	(27)
Total deferred tax expense	(3,932)	14,166	2,099
Total income tax expense	$ 49,400	$ 16,824	$ 11,852