SEGMENT INFORMATION - Segment Income or Loss Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2021	Sep. 25, 2020	Oct. 01, 2021	Sep. 25, 2020
Segment Reporting Information [Line Items]
Total consolidated segment operating income (loss)	$ 5,371	$ (1,621)	$ 3,663	$ (29,224)
Unallocated corporate expenses	(60,783)	(50,545)	(178,141)	(152,659)
Stock-based compensation	(6,436)	(3,930)	(18,867)	(13,737)
Amortization of intangibles	0	(752)	(507)	(3,214)
Non-operating expense, net	(2,899)	(2,974)	(7,260)	(10,419)
Income (loss) before income taxes	2,472	(4,595)	(3,597)	(39,643)
Operating segments
Segment Reporting Information [Line Items]
Total consolidated segment operating income (loss)	11,807	4,177	23,426	(10,470)
Corporate, non-segments
Segment Reporting Information [Line Items]
Unallocated corporate expenses	$ 0	$ (1,116)	$ (389)	$ (1,803)