FRESH-START ACCOUNTING - NARRATIVE (Details) - USD ($) $ / shares in Units, $ in Thousands		5 Months Ended
	Apr. 28, 2017	Sep. 30, 2017
Debt Instrument [Line Items]
Percentage of voting shares upon emergence (less than)	50.00%
Fair value of proved reserves	$ 397,300
Fair value of probable reserves	146,800
Fair value of possible reserves	31,700
Net asset replacement cost, fair value	$ 103,100
Reorganization Warrants
Debt Instrument [Line Items]
Warrants issued (in shares)	1,650,510
Successor warrants	$ 4,081
Expected volatility rate	40.00%
Risk-free interest rate	1.44%
Per share value (in dollars per share)	$ 34.36
Price per warrant (in dollars per share)	$ 71.23
Discounted Cash Flow Analysis
Debt Instrument [Line Items]
Risk adjusted after-tax cash flows discount, percent	11.00%
Minimum
Debt Instrument [Line Items]
Enterprise Value	$ 570,000
Maximum
Debt Instrument [Line Items]
Enterprise Value	680,000
Successor
Debt Instrument [Line Items]
Enterprise Value	642,999
Asset retirement obligations for oil and gas properties	29,061	$ 28,973
Successor warrants	$ 4,081
Risk-free interest rate		7.29%
Per share value (in dollars per share)	$ 33.41
Term of warrants	3 years
Successor | Common Stock
Debt Instrument [Line Items]
Shares outstanding (in shares)	20,356,071	20,453,444
Successor | Common Stock | Cancellation and Issuance of Equity
Debt Instrument [Line Items]
Shares outstanding (in shares)	20,356,071