Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Total [Member]
Disaggregation of Revenue [Line Items]
Total	$ 112,689	$ 48,052
Natural gas sales [Member]
Disaggregation of Revenue [Line Items]
Total	56,468	16,018
Natural gas liquids sales [Member]
Disaggregation of Revenue [Line Items]
Total	578	1,143
Oil sales [Member]
Disaggregation of Revenue [Line Items]
Total	36,795	30,891
Transportation and handling [Member]
Disaggregation of Revenue [Line Items]
Total	1,928
Marketing gas sales [Member]
Disaggregation of Revenue [Line Items]
Total	16,920
Appalachian and Illinois Basins [Member]
Disaggregation of Revenue [Line Items]
Total	79,932	19,731
Appalachian and Illinois Basins [Member] | Natural gas sales [Member]
Disaggregation of Revenue [Line Items]
Total	55,279	14,768
Appalachian and Illinois Basins [Member] | Natural gas liquids sales [Member]
Disaggregation of Revenue [Line Items]
Total
Appalachian and Illinois Basins [Member] | Oil sales [Member]
Disaggregation of Revenue [Line Items]
Total	5,805	4,963
Appalachian and Illinois Basins [Member] | Transportation and handling [Member]
Disaggregation of Revenue [Line Items]
Total	1,928
Appalachian and Illinois Basins [Member] | Marketing gas sales [Member]
Disaggregation of Revenue [Line Items]
Total	16,920
Ventura Basin [Member]
Disaggregation of Revenue [Line Items]
Total	32,757	28,321
Ventura Basin [Member] | Natural gas sales [Member]
Disaggregation of Revenue [Line Items]
Total	1,189	1,250
Ventura Basin [Member] | Natural gas liquids sales [Member]
Disaggregation of Revenue [Line Items]
Total	578	1,143
Ventura Basin [Member] | Oil sales [Member]
Disaggregation of Revenue [Line Items]
Total	30,990	25,928
Ventura Basin [Member] | Transportation and handling [Member]
Disaggregation of Revenue [Line Items]
Total
Ventura Basin [Member] | Marketing gas sales [Member]
Disaggregation of Revenue [Line Items]
Total