Supplemental Oil And Natural Gas Disclosures (Estimated Quantities Of Proved Reserves) (Details) MMcf in Thousands	1 Months Ended	11 Months Ended	12 Months Ended
	Feb. 08, 2018 MBbls MMcf	Dec. 31, 2018 a MBbls MMcf	Dec. 31, 2018 MBbls MMcf	Dec. 31, 2017 MBbls MMcf	Dec. 31, 2016 MBbls MMcf	Dec. 31, 2015 MBbls MMcf
2018 Development Drilling Programs
Total Proved Reserves:
Purchases in place			47,092
Revisions of previous quantity estimates and other		101,516
Number of Acres | a		640
Higher Average Commodity Price
Total Proved Reserves:
Revisions of previous quantity estimates and other			11,196
Oil
Total Proved Reserves:
Proved Reserves, Ending balance		25,272,000	25,272,000
Proved Developed Reserves	19,345,000	25,272,000	25,272,000	20,347,000	16,832,000	14,942,000
Proved Undeveloped Reserves	52,360,000	0	0	53,171,000	40,967,000	19,200,000
Natural gas
Total Proved Reserves:
Proved Reserves, Ending balance | MMcf		144,148	144,148
Proved Developed Reserves | MMcf	126,231	144,148	144,148	150,183	93,361	71,752
Proved Undeveloped Reserves | MMcf	284,571	0	0	283,336	222,644	83,671
Natural gas liquids
Total Proved Reserves:
Proved Reserves, Ending balance		19,792,000	19,792,000
Proved Developed Reserves	11,348,000	19,792,000	19,792,000	12,180,000	7,977,000	6,958,000
Proved Undeveloped Reserves	24,896,000	0	0	24,707,000	20,313,000	11,479,000
BOE
Total Proved Reserves:
Proved Reserves, Ending balance		69,089,000	69,089,000
Proved Developed Reserves	51,731,000	69,089,000	69,089,000	57,557,000	40,371,000	33,859,000
Proved Undeveloped Reserves	124,685,000	0	0	125,101,000	98,386,000	44,624,000
BOE | High Mesa Agreement
Total Proved Reserves:
Purchases in place					3.1
Predecessor | Oil
Total Proved Reserves:
Proved Reserves, Beginning Balance	73,518,000	71,705,000	73,518,000	57,799,000	34,142,000
Production	(521,000)	(5,053,000)		(4,850,000)	(4,001,000)
Purchases in place	0	2,658,000		725,000	1,508,000
Discoveries and extensions	0	30,026,000		20,135,000	29,903,000
Sales of reserves in place	(1,667,000)	0		(3,622,000)	(73,000)
Revisions of previous quantity estimates and other	375,000	(74,064,000)		3,331,000	(3,680,000)
Proved Reserves, Ending balance	71,705,000			73,518,000	57,799,000
Predecessor | Natural gas
Total Proved Reserves:
Proved Reserves, Beginning Balance | MMcf	433,519	410,802	433,519	316,005	155,423
Production | MMcf	(1,984)	(16,913)		(18,218)	(13,959)
Purchases in place | MMcf	0	13,331		4,860	6,754
Discoveries and extensions | MMcf	0	155,306		108,676	154,653
Sales of reserves in place | MMcf	(24,239)	0		(1,280)	(966)
Revisions of previous quantity estimates and other | MMcf	3,506	(418,378)		23,476	14,100
Proved Reserves, Ending balance | MMcf	410,802			433,519	316,005
Predecessor | Natural gas liquids
Total Proved Reserves:
Proved Reserves, Beginning Balance	36,887,000	36,244,000	36,887,000	28,290,000	18,437,000
Production	(161,000)	(2,268,000)		(1,387,000)	(956,000)
Purchases in place	0	1,751,000		401,000	613,000
Discoveries and extensions	0	19,646,000		9,640,000	14,000,000
Sales of reserves in place	(771,000)	0		0	(10,000)
Revisions of previous quantity estimates and other	289,000	(35,581,000)		(57,000)	(3,794,000)
Proved Reserves, Ending balance	36,244,000			36,887,000	28,290,000
Predecessor | BOE
Total Proved Reserves:
Proved Reserves, Beginning Balance	182,658,000	176,416,000	182,658,000	138,757,000	78,483,000
Production	(1,012,000)	(10,140,000)		(9,274,000)	(7,284,000)
Purchases in place	0	6,631,000		1,936,000	3,247,000
Discoveries and extensions	0	75,557,000		47,888,000	69,679,000
Sales of reserves in place	(6,478,000)	0		(3,836,000)	(244,000)
Revisions of previous quantity estimates and other	1,248,000	(179,375,000)		7,187,000	(5,124,000)
Proved Reserves, Ending balance	176,416,000			182,658,000	138,757,000