Supplemental disclosures to the consolidated statements of cash flows (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 21, 2017	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Net cash provided by operating activities included:
Cash payments for interest	$ 4,105	$ 17,195	$ 32,465	$ 6,266
Interest capitalized	(248)	(2,142)	(11,796)	(10,925)
Cash payments for income taxes	0	150	0	0
Cash payments for reorganization items	11,405	18,006	1,395	2,506
Non-cash investing activities included:
Asset retirement obligation additions and revisions	716	6,746	836	3,141
Oil and gas leasehold exchanges	0	816	1,399	10,913
Change in accrued oil and gas capital expenditures	$ 5,387	$ 9,534	3,630	$ 6,559
Non-cash financing activities included:
Discharge of financing lease obligations (See Note 17)			$ 9,832