FAIR VALUE MEASUREMENTS - Financial Instruments not Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Oct. 01, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	$ 97,563	$ 129,507
2022 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	36,592	35,925
2024 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	97,563	93,582
Level 2 | 2022 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	62,405	54,204
Level 2 | 2024 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 140,720	$ 125,953