Derivatives (Schedule Of Subsequent Non-designated Hedges) (Details)	2 Months Ended	12 Months Ended
	Feb. 23, 2018 MMBTU $ / Unit bbl	Dec. 31, 2017 MMBTU $ / Unit bbl
Apr'18 - Sep'18 | Liquids | OPIS - Mont Belvieu | Swap
Derivative Instruments, Gain (Loss) [Line Items]
Swap Price		31.16
Hedged Volume (Bbl) | bbl		1,000
Apr'18 - Oct'18 | Natural gas | If Nymex | Swap
Derivative Instruments, Gain (Loss) [Line Items]
Swap Price		2.990
Hedged Volume (Mmbtu) | MMBTU		10,000
Subsequent to December 31, 2017 | Apr'18 - Sep'18 | Natural gas | If Nymex | Swap
Derivative Instruments, Gain (Loss) [Line Items]
Swap Price	2.925
Hedged Volume (Mmbtu) | MMBTU	10,000
Subsequent to December 31, 2017 | Apr'18 - Sep'18 | Natural gas | If Nymex | Collar
Derivative Instruments, Gain (Loss) [Line Items]
Ceiling Price	2.67
Floor Price	2.97
Hedged Volume (Mmbtu) | MMBTU	30,000
Subsequent to December 31, 2017 | Apr'18 - Sep'18 | Liquids | OPIS - Mont Belvieu | Swap
Derivative Instruments, Gain (Loss) [Line Items]
Swap Price	34.10
Hedged Volume (Bbl) | bbl	500
Subsequent to December 31, 2017 | Feb'18 - Dec'18 | Natural gas | PEPL | Basis Swap
Derivative Instruments, Gain (Loss) [Line Items]
Swap Price	(0.678)
Hedged Volume (Mmbtu) | MMBTU	10,000
Subsequent to December 31, 2017 | Feb'18 - Dec'18 | Natural gas | NGPL Midcon | Basis Swap
Derivative Instruments, Gain (Loss) [Line Items]
Swap Price	(0.568)
Hedged Volume (Mmbtu) | MMBTU	10,000
Subsequent to December 31, 2017 | Apr'18 - Oct'18 | Natural gas | NGPL Texok | Basis Swap
Derivative Instruments, Gain (Loss) [Line Items]
Swap Price	(0.190)
Hedged Volume (Mmbtu) | MMBTU	10,000
Subsequent to December 31, 2017 | Jan'19 - Dec'19 | Natural gas | PEPL | Basis Swap
Derivative Instruments, Gain (Loss) [Line Items]
Swap Price	(0.728)
Hedged Volume (Mmbtu) | MMBTU	10,000
Subsequent to December 31, 2017 | Jan'19 - Dec'19 | Natural gas | NGPL Midcon | Basis Swap
Derivative Instruments, Gain (Loss) [Line Items]
Swap Price	(0.625)
Hedged Volume (Mmbtu) | MMBTU	10,000
Subsequent to December 31, 2017 | Jan'19 - Dec'19 | Natural gas | NGPL Texok | Basis Swap
Derivative Instruments, Gain (Loss) [Line Items]
Swap Price	(0.273)
Hedged Volume (Mmbtu) | MMBTU	20,000
Subsequent to December 31, 2017 | Jan'20 - Dec'20 | Natural gas | NGPL Texok | Basis Swap
Derivative Instruments, Gain (Loss) [Line Items]
Swap Price	(0.280)
Hedged Volume (Mmbtu) | MMBTU	20,000
Subsequent to December 31, 2017 | Apr'18 - Dec'18 | Oil | Wti Nymex | Swap
Derivative Instruments, Gain (Loss) [Line Items]
Swap Price	60.00
Hedged Volume (Bbl) | bbl	1,000