Discontinued Operations (Schedule Of The Amounts In Net Loss From Discontinued Operations) (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended	9 Months Ended
	Jan. 26, 2018	Jan. 31, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operations included in current assets						$ 121
Discontinued operations included in non-current assets						1,497
Discontinued operations included in current liabilities						43
Net income (loss) from discontinued operations			$ 46	$ 1,120	$ 55
Sale of methane facility assets	$ 2,650	$ 2,650
Disposal Group, Not Discontinued Operations [Member] | Methane Facilities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts receivable						91
Other current assets						30
Discontinued operations included in current assets						121
Property, plant, and equipment						1,681
Accumulated depreciation, depletion, and amortization						(184)
Discontinued operations included in non-current assets						1,497
Accounts payable - trade						27
Accrued and other current liabilities						16
Discontinued operations included in current liabilities						$ 43
Revenues			144	6	458
Production costs and taxes			(82)	(40)	(356)
Depreciation, depletion, and amortization			(16)	(4)	(47)
Interest income				1
Gain on sale of assets				1,157
Net income (loss) from discontinued operations			$ 46	$ 1,120	$ 55