Supplemental Oil And Gas Disclosures (Schedule Of Proved Developed And Undeveloped Oil And Gas Reserve Quantities) (Details) bbl in Thousands, Mcf in Thousands, MBoe in Thousands	8 Months Ended	12 Months Ended
	Aug. 31, 2020 MBoe bbl Mcf	Dec. 31, 2019 MBoe Mcf bbl
Proved developed and undeveloped reserves:
Beginning of year (MBoe) | MBoe	71,924	159,681
Revision of previous estimate (MBoe) | MBoe	(12,870)	(68,366)
Extension and discovery (MBoe) | MBoe	39	3,015
Infill reserves in existing proved fields (MBoe) | MBoe	238	1,506
Purchase of mineral in place (MBoe) | MBoe	112	503
Production (MBoe) | MBoe	(11,891)	(16,825)
Sales (MBoe) | MBoe	(11)	(7,590)
End of year (MBoe) | MBoe	47,541	71,924
Proved developed reserves:
Beginning of year (MBoe) | MBoe	71,924
End of year (MBoe) | MBoe	47,541	71,924
Proved undeveloped reserves
Beginning of year (MBoe) | MBoe	0
End of year (MBoe) | MBoe	0	0
Oil (bbls)
Proved developed and undeveloped reserves:
Beginning of year	12,196	22,558
Revision of previous estimates	(1,909)	(8,263)
Extensions and discoveries	8	703
Infill reserves in existing proved fields	97	271
Purchases of minerals in place	62	183
Production	(2,186)	(3,208)
Sales	(1)	(48)
End of year	8,267	12,196
Proved developed reserves:
Beginning of year	12,196
End of year	8,267	12,196
Proved undeveloped reserves
Beginning of year	0
End of year	0	0
Natural Gas Liquids (bbls)
Proved developed and undeveloped reserves:
Beginning of year	23,030	47,796
Revision of previous estimates	(4,477)	(20,961)
Extensions and discoveries	13	845
Infill reserves in existing proved fields	66	434
Purchases of minerals in place	20	101
Production	(3,444)	(4,773)
Sales	0	(412)
End of year	15,208	23,030
Proved developed reserves:
Beginning of year	23,030
End of year	15,208	23,030
Proved undeveloped reserves
Beginning of year	0
End of year	0	0
Natural gas (Mcf)
Proved developed and undeveloped reserves:
Beginning of year | Mcf	220,187	535,963
Revision of previous estimates | Mcf	(38,901)	(234,852)
Extensions and discoveries | Mcf	110	8,798
Infill reserves in existing proved fields | Mcf	452	4,806
Purchases of minerals in place | Mcf	172	1,316
Production | Mcf	(37,567)	(53,064)
Sales | Mcf	(62)	(42,780)
End of year | Mcf	144,391	220,187
Proved developed reserves:
Beginning of year | Mcf	220,187
End of year | Mcf	144,391	220,187
Proved undeveloped reserves
Beginning of year | Mcf	0
End of year | Mcf	0	0