Oil and Gas Reserves Information (Unaudited) - Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Reserves (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Aug. 13, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Flows Relating to Proved Reserves:
Future Cash Flows	$ 13,078,155	$ 8,054,092
Future Costs:
Production	(3,562,042)	(2,160,912)
Development and Abandonment	(3,171,351)	(1,800,335)
Future Income Taxes	(676,759)	(622,241)
Future Net Cash Flows	5,668,003	3,470,604
10% Discount Factor	(2,754,792)	(1,996,764)
Standardized Measure of Discounted Future Net Cash Flows	$ 2,913,211	$ 1,473,840	$ 1,317,383
Predecessor
Cash Flows Relating to Proved Reserves:
Future Cash Flows			6,384,203	$ 3,588,764
Future Costs:
Production			(1,804,559)	(986,398)
Development and Abandonment			(1,945,141)	(672,559)
Future Income Taxes			(199,589)	5,239
Future Net Cash Flows			2,434,914	1,935,046
10% Discount Factor			(1,556,927)	(1,053,502)
Standardized Measure of Discounted Future Net Cash Flows			$ 877,987	881,544	$ 429,275
Assets Held for Sale | Predecessor
Future Costs:
Standardized Measure of Discounted Future Net Cash Flows				$ 109,134