LONG-TERM DEBT - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Apr. 03, 2018
Debt Instrument [Line Items]
Gross, long-term debt	$ 247,204
Less: Debt issuance costs, net	(2,389)	$ (3,119)
Less: Unamortized discount, net	(2,159)	(2,825)
Long-term debt	242,656	287,882
Senior secured term loans
Debt Instrument [Line Items]
Gross, long-term debt	$ 247,204	$ 293,826	$ 412,100

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Amount, after accumulated amortization, of debt discount.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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