LONG-TERM DEBT / INTEREST EXPENSE - Schedule of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Debt Instrument
Other	$ (9)	$ 5
Interest expense, net	32,956	21,773
Revolving Credit Facility
Debt Instrument
Interest expense (excluding amortization)	0	316
Senior Credit Facility
Debt Instrument
Amortization of discount and debt issuance costs	6,043	1,755
Interest expense	30,313	19,207
Senior Credit Facility \| FILO Term Loan \| Revolving Credit Facility
Debt Instrument
Interest expense (excluding amortization)	123	132
FILO Asset-based Term Loan Facility \| FILO Term Loan \| Term Loan
Debt Instrument
Interest expense (excluding amortization)	6,751	2,122
Notes \| Convertible Senior Notes
Debt Instrument
Interest expense (excluding amortization)	707	707
Amortization of conversion feature	1,701	1,610
Amortization of discount and debt issuance costs	244	244
Interest expense	2,652	2,561
Tranche B-1 \| Senior Credit Facility \| Term Loan Facility
Debt Instrument
Interest expense (excluding amortization)	928	8,058
Tranche B-2 \| Senior Credit Facility \| Term Loan Facility
Debt Instrument
Interest expense (excluding amortization)	$ 16,468	$ 6,824

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Other Interest Income (Expense), Nonoperating, Net

+ References

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- Definition

Amount of amortization expense attributable to debt discount (premium) and debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6036836-161870

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Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

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-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

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The net amount of nonoperating interest income (expense).

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