Derivatives (Summary Of Derivative Instruments Contracts) (Details)	Sep. 30, 2021 MMBTU $ / MMBTU $ / bbl bbl
Natural Gas Fixed Price Swaps [Member] | 2022
Derivative [Line Items]
Contract total volume - Gas/Natural gas | MMBTU	3,869,000
Contract average price | $ / MMBTU	2.91
Natural Gas Fixed Price Swaps [Member] | 2023
Derivative [Line Items]
Contract total volume - Gas/Natural gas | MMBTU	1,100,000
Contract average price | $ / MMBTU	3.07
Oil Fixed Price Swaps [Member] | 2022
Derivative [Line Items]
Contract average price | $ / bbl	44.25
Contract total volume - Oil | bbl	138,000
Oil Fixed Price Swaps [Member] | 2023
Derivative [Line Items]
Contract average price | $ / bbl	46.23
Contract total volume - Oil | bbl	30,000