Future development costs estimated to be spent in year one

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- Definition

Proved Developed And Undeveloped Reserve Increase (Decrease) In Reserves

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- Definition

Proved Developed And Undeveloped Reserve, Revisions Of Previous Estimates, Energy

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- Definition

Proved Undeveloped Reserves, Postponement of Drilling Period

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- Definition

The revenues derived from sales of oil or gas in each geographic area during the reporting period divided by the number of barrels of oil produced or thousands of cubic feet of gas produced.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1204
-Paragraph (b)
-Subparagraph (1)

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

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- Definition

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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Supplemental Information On Oil And Gas Exploration And Production Activities (Unaudited) (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) Mcfe $ / MMBTU $ / bbl	Dec. 31, 2014	Dec. 31, 2014 USD ($)	Dec. 31, 2014 $ / MMBTU	Dec. 31, 2014 $ / bbl	Dec. 31, 2014 Mcfe	Dec. 31, 2013 USD ($)	Dec. 31, 2013 $ / MMBTU	Dec. 31, 2013 $ / bbl	Dec. 31, 2013 Mcfe
Reserve Quantities [Line Items]
Price per unit (usd per MMbls or MMcf)	2.59			4.35	94.99			3.67	96.78
Future Development Costs Estimated To Be Spent In Year One \| $	$ 170.3		$ 177.6				$ 158.4
Diamondback Energy, Inc
Reserve Quantities [Line Items]
Ownership interest		7.20%	7.20%	7.20%	7.20%	7.20%
Grizzly
Reserve Quantities [Line Items]
Ownership interest	24.9999%
Utica Shale
Reserve Quantities [Line Items]
Increase (decrease) in reserve during the period	1,044,500					786,000				166,832
Southern Louisiana and Utica Fields
Reserve Quantities [Line Items]
Decrease in reserves relating to change in estimates	444,314					15,837
Proved Undeveloped Reserves, Postponement of Drilling Period		5 years
Paloma and AEU
Reserve Quantities [Line Items]
Increase (decrease) in reserve during the period	371,663
Rhino
Reserve Quantities [Line Items]
Increase (decrease) in reserve during the period						12,000
Oil and condensate sales
Reserve Quantities [Line Items]
Price per unit (usd per MMbls or MMcf) \| $ / bbl	50.28
Natural Gas Liquids
Reserve Quantities [Line Items]
Price per unit (usd per MMbls or MMcf) \| $ / bbl	13.21				44.84				41.23