Acquired Proved Reserves by Type of Reserve, Percentage

No definition available.

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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

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 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)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3179-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

+ Details

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Period Type:	duration

- 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))

-URI http://asc.fasb.org/extlink&oid=6949603&loc=d3e511914-122862

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 19

-Paragraph 59F

-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 SEC

-Name Regulation S-X (SX)

-Number 210

-Article 4

-Section 10

-Paragraph a

-Subparagraph 2

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6821537&loc=d3e61831-109447

+ Details

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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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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- 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

+ Details

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Subsequent Events (Details) (USD $)	12 Months Ended																0 Months Ended
Subsequent Events (Details) (USD $)	Dec. 31, 2011 mmboe	Dec. 31, 2010 mmboe	Dec. 31, 2009 mmboe	Dec. 31, 2008 mmboe	Dec. 31, 2011 Oil Reserves MBbls	Dec. 31, 2010 Oil Reserves MBbls	Dec. 31, 2009 Oil Reserves MBbls	Dec. 31, 2008 Oil Reserves MBbls	Dec. 31, 2011 Natural Gas Liquids Reserves MBbls	Dec. 31, 2010 Natural Gas Liquids Reserves MBbls	Dec. 31, 2009 Natural Gas Liquids Reserves MBbls	Dec. 31, 2008 Natural Gas Liquids Reserves MBbls	Dec. 31, 2011 Natural Gas Reserves MMcf	Dec. 31, 2010 Natural Gas Reserves MMcf	Dec. 31, 2009 Natural Gas Reserves MMcf	Dec. 31, 2008 Natural Gas Reserves MMcf	Feb. 14, 2012 Feb 14, 2012, Permian Basin Purchase Agreement mmboe	Feb. 14, 2012 Feb 14, 2012, Permian Basin Oil Reserves Purchase Agreement	Feb. 14, 2012 Feb 14, 2012, Permian Basin Natural Gas Liquids Reserves Purchase Agreement	Feb. 14, 2012 Feb 14, 2012, Permian Basin Natural Gas Reserves Purchase Agreement	Feb. 21, 2012 Feb 21, 2012, Reeves County Purchase Agreement well	Feb. 21, 2012 Feb 21, 2012, Reeves County Purchase Agreement, First Clause A well	Feb. 21, 2012 Feb 21, 2012, Reeves County Purchase Agreement, Second Clause A well
Subsequent Event [Line Items]
Consideration - Purchase Price																	$ 63,294,000
Proved reserves acquired	343.1	302.9	257.8	264.1	129,578	103,262	77,963	62,034	53,957	40,601	30,257	28,953	957,368	954,387	897,546	1,038,453	8.5
Percentage of undeveloped portion of proved reserves	69.00%	77.00%	81.00%														80.00%
Acquired proved reserves by type of reserve, percentage																		64.00%	22.00%	14.00%
Cash received from sale of oil properties																					$ 18,000,000
Undivided interest percentage																					50.00%	50.00%	50.00%
Existing wells																					3	2	1
Net acres																						4,829	51,720