Summary Of Significant Accounting Policies (Schedule Of Segment's Revenues) (Details)	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2020	Aug. 31, 2020	Dec. 31, 2019
CVR Refining, LP | Oil and Natural Gas
Revenue, Major Customer [Line Items]
Segment's revenues	14.00%	15.00%	14.00%
Plains Marketing L.P. | Oil and Natural Gas
Revenue, Major Customer [Line Items]
Segment's revenues		11.00%
EOG Resources, Inc. | Drilling
Revenue, Major Customer [Line Items]
Segment's revenues	28.00%	20.00%	12.00%
QEP Resources, Inc. | Drilling
Revenue, Major Customer [Line Items]
Segment's revenues	23.00%	10.00%	12.00%
Citizen Energy III, LLC | Drilling
Revenue, Major Customer [Line Items]
Segment's revenues	16.00%
Slawson Exploration Company, Inc | Drilling
Revenue, Major Customer [Line Items]
Segment's revenues	16.00%	21.00%	11.00%
Cimarex Energy Co. | Drilling
Revenue, Major Customer [Line Items]
Segment's revenues	12.00%
ONEOK, Inc. | Mid-Stream
Revenue, Major Customer [Line Items]
Segment's revenues	28.00%	31.00%	33.00%
Range Resources Corporation | Mid-Stream
Revenue, Major Customer [Line Items]
Segment's revenues	15.00%	21.00%	13.00%
Centerpoint Energy Service, Inc. | Mid-Stream
Revenue, Major Customer [Line Items]
Segment's revenues			10.00%