LONG-TERM DEBT - Components of Long-term Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Borrowings [Abstract]
Less: current portion	$ (3,300)	$ (3,300)
Unamortized debt issuance costs	8,700	9,600
Carrying Value
Borrowings [Abstract]
Total long-term debt	328,350	330,000
Less: current portion	(3,300)	(3,300)
Long-term debt less current maturities	325,050	326,700
Carrying Value | ABL Revolver
Borrowings [Abstract]
Total long-term debt	0	0
Carrying Value | Term Loan B
Borrowings [Abstract]
Total long-term debt	328,350	330,000
Fair Value
Borrowings [Abstract]
Total long-term debt	328,350	325,875
Less: current portion	(3,300)	(3,259)
Long-term debt less current maturities	325,050	322,616
Fair Value | ABL Revolver
Borrowings [Abstract]
Total long-term debt	0	0
Fair Value | Term Loan B
Borrowings [Abstract]
Total long-term debt	$ 328,350	$ 325,875