INDEBTEDNESS - Revolving credit agreement (Details)			3 Months Ended		21 Months Ended
	Mar. 30, 2020	Oct. 10, 2018 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Jul. 02, 2020 USD ($)	Jun. 29, 2020 USD ($)	Jun. 28, 2020 USD ($)	Jun. 05, 2020 USD ($)	Jan. 17, 2020 USD ($) installment	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Repayments of lines of credit			$ 17,250,000	$ 0
Long-term debt			97,750,000							$ 115,000,000
Amortization of debt financing costs			707,000	140,000
Subsequent Event
Debt Instrument [Line Items]
Amount of prepetition obligations to be settled in cash							$ 9,200,000
Accrued and unpaid interest							700,000
Amount of participations in new loans							$ 55,000,000
Line of Credit | Revolving Credit Agreement | Revolving Credit Facility
Debt Instrument [Line Items]
Agreement term		5 years
Line of credit facility, maximum borrowing capacity		$ 500,000,000.0
Line of credit facility, borrowing base		$ 115,000,000.0	90,000,000.0						$ 90,000,000
Borrowing base deficiency			7,800,000						$ 25,000,000
Line of credit facility, commitment fee percentage		0.50%
Long-term debt			97,750,000
Amortization of debt financing costs			$ 707,000	$ 140,000
Ratio of total debt to EBITDAX (not more than)		400.00%
Ratio of current assets to current liabilities (not less than)		100.00%
Percentage of production required to be maintained (not less than)			75.00%
Minimum period of swap agreements maintained			24 months
Covenant, borrowing base deficiency, number of equal monthly installments (in installments) | installment									4
Extension term	45 days
Line of Credit | Revolving Credit Agreement | Letter of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 5,000,000.0
Line of Credit | Other Current Assets | Revolving Credit Agreement | Revolving Credit Facility
Debt Instrument [Line Items]
Unamortized debt issuance costs			$ 2,100,000							$ 2,600,000
Line of Credit | Subsequent Event | Revolving Credit Agreement | Revolving Credit Facility
Debt Instrument [Line Items]
Borrowing base deficiency								$ 7,800,000
Repayments of lines of credit					$ 17,300,000
Long-term debt						$ 89,900,000
Line of Credit | Affiliate of Varde | Subsequent Event | Revolving Credit Agreement | Revolving Credit Facility
Debt Instrument [Line Items]
Long-term debt						$ 25,700,000