INDEBTEDNESS - Summary of long-term debt instruments (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total indebtedness		$ 104,924	$ 115,000
Less: current portion		(30,000)	(115,000)
Total long-term debt, net of current portion		0	0
Revolving Credit Agreement, due October 2023 | Line of Credit
Debt Instrument [Line Items]
Total indebtedness	[1]	74,924	$ 115,000
Debtor in-possession credit facility		30,000
Less: debt classified as liabilities subject to compromise		$ (74,924)

[1] The balance outstanding under the Revolving Credit Agreement is classified as liabilities subject to compromise. See Note 3 – Summary of Significant Accounting Policies and Estimates.