Discontinued Operations (Schedule Of The Amounts In Net Loss From Discontinued Operations) (Details) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
Jan. 26, 2018	Jun. 30, 2018	Jun. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net income from discontinued operations		$ 10	$ 1,120
Sale of methane facility assets	$ 2,650
Discontinued Operations [Member] \| Methane Facilities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues			6
Production costs and taxes		10	(40)
Depreciation, depletion, and amortization			(4)
Interest income			1
Gain on sale of assets			1,157
Net income from discontinued operations		$ 10	$ 1,120

Disposal Group, Including Discontinued Operation, Depreciation Depletion And Amortization

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Disposal Group, Including Discontinued Operation, Gain (Loss) On Disposition Of Property Plant Equipment

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Disposal Group, Including Discontinued Operation,Production Costs And Taxes

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Amount of interest income attributable to disposal group, including, but not limited to, discontinued operation.

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Amount of revenue attributable to disposal group, including, but not limited to, discontinued operation.

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Amount after tax of income (loss) from a discontinued operation including the portion attributable to the noncontrolling interest. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of cash inflow from the sale of other assets as part of operating activities.

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