Derivatives (Summary Of Derivative Instruments Contracts) (Details)	Mar. 31, 2021 MMBTU $ / MMBTU $ / bbl bbl
Natural Gas Costless Collars [Member] | Remaining 2021 [Member]
Derivative [Line Items]
Contract total volume - Gas/Natural gas | MMBTU	2,207,500
Natural Gas Costless Collars [Member] | Remaining 2021 [Member] | Minimum [Member]
Derivative [Line Items]
Contract average price	2.35
Natural Gas Costless Collars [Member] | Remaining 2021 [Member] | Maximum [Member]
Derivative [Line Items]
Contract average price	3.04
Natural Gas Costless Collars [Member] | 2022 [Member]
Derivative [Line Items]
Contract total volume - Gas/Natural gas | MMBTU	2,200,500
Natural Gas Costless Collars [Member] | 2022 [Member] | Minimum [Member]
Derivative [Line Items]
Contract average price	2.40
Natural Gas Costless Collars [Member] | 2022 [Member] | Maximum [Member]
Derivative [Line Items]
Contract average price	3.12
Natural Gas Costless Collars [Member] | 2023 [Member]
Derivative [Line Items]
Contract total volume - Gas/Natural gas | MMBTU	86,000
Natural Gas Costless Collars [Member] | 2023 [Member] | Minimum [Member]
Derivative [Line Items]
Contract average price	2.25
Natural Gas Costless Collars [Member] | 2023 [Member] | Maximum [Member]
Derivative [Line Items]
Contract average price	2.96
Natural Gas Fixed Price Swaps [Member] | Remaining 2021 [Member]
Derivative [Line Items]
Contract total volume - Gas/Natural gas | MMBTU	1,166,500
Contract average price	2.80
Natural Gas Fixed Price Swaps [Member] | 2022 [Member]
Derivative [Line Items]
Contract total volume - Gas/Natural gas | MMBTU	377,500
Contract average price	2.61
Natural Gas Fixed Price Swaps [Member] | 2023 [Member]
Derivative [Line Items]
Contract total volume - Gas/Natural gas | MMBTU	84,000
Contract average price	2.56
Oil Costless Collars [Member] | Remaining 2021 [Member]
Derivative [Line Items]
Contract total volume - Oil | bbl	33,500
Oil Costless Collars [Member] | Remaining 2021 [Member] | Minimum [Member]
Derivative [Line Items]
Contract average price | $ / bbl	36.76
Oil Costless Collars [Member] | Remaining 2021 [Member] | Maximum [Member]
Derivative [Line Items]
Contract average price | $ / bbl	45.00
Oil Costless Collars [Member] | 2022 [Member]
Derivative [Line Items]
Contract total volume - Oil | bbl	68,500
Oil Costless Collars [Member] | 2022 [Member] | Minimum [Member]
Derivative [Line Items]
Contract average price | $ / bbl	40.25
Oil Costless Collars [Member] | 2022 [Member] | Maximum [Member]
Derivative [Line Items]
Contract average price | $ / bbl	50.35
Oil Fixed Price Swaps [Member] | Remaining 2021 [Member]
Derivative [Line Items]
Contract average price | $ / bbl	39.37
Contract total volume - Oil | bbl	87,000
Oil Fixed Price Swaps [Member] | 2022 [Member]
Derivative [Line Items]
Contract average price | $ / bbl	41.51
Contract total volume - Oil | bbl	59,000