Subsequent Events (Details Textuals) (Riley Ridge Phase 2 [Member], USD $) In Millions, unless otherwise specified	Aug. 01, 2011
Riley Ridge Phase 2 [Member]
Subsequent Event [Line Items]
Working interest in business acquisition	57.50%
Contract price before closing adjustments, including contingent consideration, for acquisition	$ 191.00
Contingent payment to be paid at the time the property's gas processing facility is operational and meets specific performance conditions	$ 15.00
Business Acquisition Percentage Of Additional Working Interests	33.00%

Contract price before closing adjustments, including contingent consideration, for acquisition

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- Definition

Acquisition of working interests (non-specific)

+ Details

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- Definition

Working interest in oil, natural gas, other mineral properties, or pipelines acquired through a business acquisition.

+ Details

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- Definition

Amount of potential cash payments that could result from the contingent consideration arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 141
-Paragraph 51
-Subparagraph f
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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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- 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.

+ Details

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