Derivatives (Schedule of Non-designated Hedges Outstanding) (Details)	12 Months Ended
	Dec. 31, 2018 MMBTU $ / Unit bbl
Natural gas | Swap | If Nymex | Jan'19 - Mar'19
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Volume (Mmbtu) | MMBTU	50,000
Swap Price	3.440
Natural gas | Swap | If Nymex | Apr'19 - Dec'19
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Volume (Mmbtu) | MMBTU	40,000
Swap Price	2.900
Natural gas | Basis Swap | PEPL | Jan'19 - Dec'19
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Volume (Mmbtu) | MMBTU	20,000
Swap Price	(0.659)
Natural gas | Basis Swap | NGPL Midcon | Jan'19 - Dec'19
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Volume (Mmbtu) | MMBTU	10,000
Swap Price	(0.625)
Natural gas | Basis Swap | NGPL Texok | Jan'19 - Dec'19
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Volume (Mmbtu) | MMBTU	30,000
Swap Price	(0.265)
Natural gas | Basis Swap | NGPL Texok | Jan'20 - Dec'20
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Volume (Mmbtu) | MMBTU	30,000
Swap Price	(0.275)
Natural gas | Collar | If Nymex | Jan'19 - Dec'19
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Volume (Mmbtu) | MMBTU	20,000
Floor Price	2.63
Ceiling Price	3.03
Natural gas | Three-way collar | If Nymex | Jan'19 - Mar'19
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Volume (Mmbtu) | MMBTU	30,000
Floor Price	3.17
Ceiling Price	4.32
Subfloor Price	2.92
Crude Oil | Three-way collar | Wti Nymex | Jan'19 - Dec'19
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Volume (Bbl) | bbl	4,000
Floor Price	61.25
Ceiling Price	72.93
Subfloor Price	51.25