Supplemental disclosures to the consolidated statements of cash flows (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	9 Months Ended
	Mar. 21, 2017	Sep. 30, 2017	Sep. 30, 2018
Net cash provided by operating activities included:
Cash payments for interest		$ 13,196	$ 5,755
Interest capitalized		(1,245)	(7,155)
Cash payments for income taxes		150	0
Cash payments for reorganization items		16,930	2,161
Non-cash investing activities included:
Asset retirement obligation additions and revisions		2,746	1,234
Change in accrued oil and gas capital expenditures		$ 10,598	$ 7,222
Predecessor
Net cash provided by operating activities included:
Cash payments for interest	$ 4,105
Interest capitalized	(248)
Cash payments for income taxes	0
Cash payments for reorganization items	11,405
Non-cash investing activities included:
Asset retirement obligation additions and revisions	716
Change in accrued oil and gas capital expenditures	$ 5,387