Property and Equipment, Net (Details 1) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative [Abstract]
Total unproved properties	$ 4,872	$ 5,416
Ventura Basin [Member] | California [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative [Abstract]
Total unproved properties	1,602	1,595
Illinois Basin [Member] | Indiana [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative [Abstract]
Total unproved properties	432	432
Illinois Basin [Member] | Illinois [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative [Abstract]
Total unproved properties	136	136
Appalachian Basin [Member] | Kentucky [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative [Abstract]
Total unproved properties	461	920
Appalachian Basin [Member] | Ohio [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative [Abstract]
Total unproved properties	66	66
Appalachian Basin [Member] | Tennessee [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative [Abstract]
Total unproved properties	1,869	1,869
Appalachian Basin [Member] | West Virginia [Member]
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative [Abstract]
Total unproved properties	$ 306	$ 398