Oil and Natural Gas Property Transactions - VPP Volume Remaining to Be Delivered Table (Details) - VPP 9 Mid-Continent [Member] Mcf in Millions, MMBbls in Millions, MBbls in Millions, Mcfe in Billions	3 Months Ended
	Mar. 31, 2017 Mcfe MMBbls Mcf	May 31, 2011 Mcfe MBbls Mcf
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Energy) | Mcfe		177.0
Reserve Volume Remaining [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Term remaining (in months)	47 months
Proved Developed Reserves (Energy) | Mcfe	52.5
Oil [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Volume) | MBbls		1.7
Oil [Member] | Reserve Volume Remaining [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Volume) | MMBbls	0.5
Natural Gas [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Volume) | Mcf		138,000.0
Natural Gas [Member] | Reserve Volume Remaining [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Volume) | Mcf	42.8
NGL [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Volume) | MBbls		4.8
NGL [Member] | Reserve Volume Remaining [Member]
VPP Volumes Remaining to be Delivered [Line Items]
Proved Developed Reserves (Volume) | MMBbls	1.1