Acquired Proved Reserves by Type of Reserve, Percentage

No definition available.

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- Definition

The amount of Accounts Payable recognized as of the acquisition date.

+ References

No definition available.

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- Definition

The amount of Accounts Receivable recognized as of the acquisition date.

+ References

No definition available.

+ Details

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- Definition

The amount of Asset Retirement Obligation recognized as of the acquisition date.

+ References

No definition available.

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- Definition

The Net amount recognized as of the acquisition date for the aggregate identifiable assets acquired in excess of or less than the aggregate liabilities assumed.

+ References

No definition available.

+ Details

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- Definition

The amount of Proved Properties recognized as of the acquisition date.

+ References

No definition available.

+ Details

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- Definition

The amount of Unproved Properties assumed at the acquisition date.

+ References

No definition available.

+ Details

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- Definition

Percentage of Undeveloped Portion of Proved Reserves

+ References

No definition available.

+ Details

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- Definition

Significant Acquisitions and Disposals, Percentage of Undivided Interest, Sale

+ References

No definition available.

+ Details

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- Definition

Standardized Measure of Discounted Percentage of Future Net Cash Flow of Proved Oil and Gas Reserves, Other

+ References

No definition available.

+ Details

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- Definition

The charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 45

-Paragraph 4

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 28

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 144

-Paragraph 45, 46, 47

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

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- Definition

Undeveloped acreage is considered to be those lease acres on which wells have not been drilled or completed to a point that would permit the production of commercial quantities of oil and gas regardless of whether or not such acreage contains proved reserves. Net acres is the sum of the fractional interest owned based on working interests or other economic arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Industry Guide

-Number 2

-Paragraph 5

+ Details

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- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

+ Details

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- Definition

The cash inflow to dispose of long-lived, physical assets and mineral interests in oil and gas properties used for normal oil and gas operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (c)

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 15

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 16

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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- Definition

The net quantity of proved reserves as of the balance sheet date. Proved oil reserves are the estimated quantities of crude oil and natural gas liquids which geological and engineering data demonstrate with reasonable certainty to be recoverable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-10.(a)(2))

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 4

-Section 10

-Paragraph a

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-Name Accounting Standards Codification

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-SubTopic 235

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- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 5

-Section 03

-Paragraph 1

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

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-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

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- Definition

The value of all consideration given or received by the Entity in the significant acquisition or disposal.

+ References

No definition available.

+ Details

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- Definition

The number of wells in the process of being drilled in each geographic area as of the date listed.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Industry Guide

-Number 2

-Paragraph 7

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Acquisition and Dispositions of Oil and Gas Properties (Details) (USD $)	3 Months Ended		6 Months Ended		0 Months Ended		3 Months Ended	0 Months Ended													1 Months Ended		0 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Feb. 21, 2012 Feb 21, 2012, Reeves County [Member] A well	Feb. 14, 2012 Feb 14, 2012, Permian Basin [Member] mmboe	Jun. 30, 2012 Feb 14, 2012, Permian Basin [Member]	Feb. 14, 2012 Feb 14, 2012, Permian Basin [Member] Oil Reserves	Feb. 14, 2012 Feb 14, 2012, Permian Basin [Member] Natural Gas Liquids Reserves	Feb. 14, 2012 Feb 14, 2012, Permian Basin [Member] Natural Gas Reserves	Dec. 27, 2011 Dec 27, 2011, Permian Basin [Member] mmboe	Dec. 27, 2011 Dec 27, 2011, Permian Basin [Member] Oil Reserves	Dec. 27, 2011 Dec 27, 2011, Permian Basin [Member] Natural Gas Liquids Reserves	Dec. 27, 2011 Dec 27, 2011, Permian Basin [Member] Natural Gas Reserves	Nov. 16, 2011 Nov 16, 2011, Permian Basin [Member] mmboe	Nov. 16, 2011 Nov 16, 2011, Permian Basin [Member] Oil Reserves	Nov. 16, 2011 Nov 16, 2011, Permian Basin [Member] Natural Gas Liquids Reserves	Nov. 16, 2011 Nov 16, 2011, Permian Basin [Member] Natural Gas Reserves	Jul. 31, 2011 July 2011, Permian Basin	Apr. 30, 2011 April 2011, Permian Basin A	Mar. 31, 2012 Contingent Sales Agreement [Member] Feb 21, 2012, Reeves County [Member]	Feb. 14, 2012 Contingent Sales Agreement [Member] Feb 21, 2012, Reeves County [Member] A	May 01, 2012 Contingent Sales Agreement [Member] New Contract, Second Clause [Member] Feb 21, 2012, Reeves County [Member] A
Significant Acquisitions and Disposals [Line Items]
Asset Impairment Charges	$ 0	$ 0	$ 21,545,000	$ 0
Standardized Measure of Discounted Percentage of Future Net Cash Flow of Proved Oil and Gas Reserves, Other	10.00%
Significant Acquisitions and Disposals, Percentage of Undivided Interest, Sale					50.00%																50.00%		50.00%
Wells in Process of Drilling					3
Proceeds from Sale of Oil and Gas Property and Equipment					18,000,000
Gas and Oil Acreage, Undeveloped, Net					4,829															11,000		51,720	51,720
Consideration - Purchase Price						67,615,000					55,994,000				161,967,000				20,000,000	37,000,000
Proved Developed and Undeveloped Reserves, Net						8.1					3.4				13.6
Percentage of Undeveloped Portion of Proved Reserves						81.00%					77.00%				76.00%
Acquired Proved Reserves by Type of Reserve, Percentage								64.00%	22.00%	14.00%		61.00%	24.00%	15.00%		59.00%	25.00%	16.00%
Recognized amounts of identifiable assets acquired and liabilities assumed
Proved properties						65,581,000					32,045,000				151,544,000
Unproved leasehold properties						911,000					23,686,000				7,883,000
Accounts receivable						1,358,000					680,000				3,070,000
Accounts payable						(25,000)					(244,000)				(388,000)
Asset retirement obligation						(210,000)					(173,000)				(142,000)
Total identifiable net assets						67,615,000					55,994,000				161,967,000
Operating revenues	470,355,000	330,399,000	888,799,000	816,763,000			5,300,000
Operating income	$ 220,598,000	$ 106,335,000	$ 324,768,000	$ 266,216,000			$ 2,600,000