Other Property And Equipment (Schedule Of Other Property And Equipment) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Gross Cost	$ 376,000	$ 401,000
Accumulated depreciation	186,000	266,000
Manufactured Methane facilities, net	190,000	135,000
Depreciation expense	73,000	66,000
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross Cost	20,000	20,000
Accumulated depreciation	20,000	20,000
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Gross Cost	293,000	318,000
Accumulated depreciation	103,000	183,000
Manufactured Methane facilities, net	$ 190,000	$ 135,000
Other [Member]
Property, Plant and Equipment [Line Items]
Depreciable Life	5 years	5 years
Gross Cost	$ 63,000	$ 63,000
Accumulated depreciation	$ 63,000	$ 63,000
Minimum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciable Life	5 years	5 years
Minimum [Member] | Vehicles [Member]
Property, Plant and Equipment [Line Items]
Depreciable Life	2 years	2 years
Maximum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciable Life	7 years	7 years
Maximum [Member] | Vehicles [Member]
Property, Plant and Equipment [Line Items]
Depreciable Life	5 years	5 years