Supplemental Oil And Gas Disclosures (Schedule Of The Oil And Natural Gas Property Costs Not Being Amortized) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Supplemental Oil And Gas Disclosures [Abstract]
Undeveloped Leasehold Acquired	$ 59,691	$ 49,923	$ 17,766	$ 58,252
Undeveloped Leasehold Acquired, Total	$ 185,632

The sum of the capitalized costs incurred during the period of unproved properties excluded from amortization including acquisition costs, exploration costs, development costs, and production costs.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 4

-Section 10

-Paragraph c

-Subparagraph 3(ii)(A)

Reference 2: 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.(c)(7)(ii))

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

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration