Other Income (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Proceeds from Contributions from Affiliates	$ 392	$ 2,314
Gas Gathering, Transportation, Marketing and Processing Revenue	3,153	2,748
Rental Income, Nonoperating	8,842	9,196
Royalty Revenue	8,785	2,230
Revenue, Coal Services	3,541	0
Interest Income, Other	1,543	214
Right of Way Income	1,001	15,733
Other Nonoperating Income	1,501	1,345
Other Income (including equity earnings)	40,696	48,131
CONE [Member]
Proceeds from Contributions from Affiliates	$ 11,938	$ 14,351

Right of Way Income

No definition available.

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- Definition

Revenue related to midstream and downstream gas activities. May include the following: gathering from wells, processing to remove impurities, storage, transmission, and the sale of natural gas and related products.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=51678428&loc=d3e62246-109447

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 932
-SubTopic 235
-Section 50
-Paragraph 23
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51678428&loc=d3e62136-109447

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- Definition

Amount of interest income earned from interest bearing assets not separately disclosed.

+ References

No definition available.

+ Details

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- Definition

Reflects the sum of all other revenue and income recognized by the entity in the period not otherwise specified in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.4)
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

+ Details

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- Definition

The aggregate amount of other income amounts, the components of which are not separately disclosed on the income statement, resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) profits on securities (net of losses), and (d) miscellaneous other income items.

+ References

+ Details

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- Definition

The cash inflow from an entity that is affiliated with the entity by means of direct or indirect ownership.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3255-108585

+ Details

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- Definition

Income earned by providing the use of assets to an outside party in exchange for a payment or series of payments that is nonoperating in nature.

+ References

+ Details

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- Definition

Revenue from services rendered related to coal (mine services, transportation, and others) during the reporting period.

+ References

+ Details

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- Definition

Revenue earned during the period from the leasing or otherwise lending to a third party the entity's rights or title to certain property. Royalty revenue is derived from a percentage or stated amount of sales proceeds or revenue generated by the third party using the entity's property. Examples of property from which royalties may be derived include patents and oil and mineral rights.

+ References

+ Details

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