FINANCIAL INSTRUMENTS - Carrying Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Current portion of long-term debt—related party	$ 0	$ (816)
Long-term debt—related party, net	(1,015)	(1,997)
Debt issuance costs	2,529	2,938
Carrying value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Current portion of long-term debt	(13,750)	(13,750)
Long-term debt, net (a)	(244,971)	(258,312)
Current portion of long-term debt—related party	0	(816)
Long-term debt—related party, net	(1,015)	(1,997)
Fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Current portion of long-term debt	(12,753)	(13,802)
Long-term debt, net (a)	(229,556)	(262,230)
Current portion of long-term debt—related party	0	(837)
Long-term debt—related party, net	$ (1,092)	$ (2,048)

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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Carrying amount as of the balance sheet date of obligations due all related parties. For classified balance sheets, represents the current portion of such liabilities (due within one year or within the normal operating cycle if longer).

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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