Manufactured Methane (Narrative) (Details) - Methane Project [Member] - USD ($)	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Methane Project [Line Items]
Date methane facilities were placed into service	Apr. 01, 2009
Landfill closure date	Dec. 01, 2041
Depreciation expense	$ 47,000	$ 46,000