Manufactured Methane Facilities (Schedule Of The Manufactured Methane Facilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Methane Project [Line Items]
Manufactured Methane facilities, net of impairment	$ 422	$ 445
Accumulated depreciation	(282)	(245)
Manufactured Methane facilities, net	140	200
Methane Project [Member]
Methane Project [Line Items]
Manufactured Methane facilities, net of impairment	1,681	1,633
Accumulated depreciation	(122)	(60)
Manufactured Methane facilities, net	$ 1,559	$ 1,573