CONSOLIDATED BALANCE SHEETS Parenthetical (USD $)	Dec. 31, 2014	Dec. 31, 2013
Common Stock, Shares, Outstanding	67,463,060us-gaap_CommonStockSharesOutstanding	67,056,441us-gaap_CommonStockSharesOutstanding
Treasury Stock, Shares	0us-gaap_TreasuryStockShares	22,412us-gaap_TreasuryStockShares
Common Stock, Shares, Issued	67,463,060us-gaap_CommonStockSharesIssued	67,078,853us-gaap_CommonStockSharesIssued
Common Stock, Shares Authorized	200,000,000us-gaap_CommonStockSharesAuthorized	200,000,000us-gaap_CommonStockSharesAuthorized
Common Stock, Par Value Per Share	$ 0.01	$ 0.01
Oil and Gas Property, Successful Effort Method, Accumulated Depreciation, Depletion and Amortization	$ 3,233,012,000	$ 2,583,698,000
Assets Held-for-sale [Member]
Oil and Gas Property, Successful Effort Method, Accumulated Depreciation, Depletion and Amortization	22,482,000	7,390,000
Other Capitalized Property Plant and Equipment [Member]
Oil and Gas Property, Successful Effort Method, Accumulated Depreciation, Depletion and Amortization	$ 37,079,000	$ 28,775,000

Face amount or stated value per share of common stock.

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

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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

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

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Amount of accumulated depreciation, depletion and amortization of oil and gas property carried under the successful effort method. Oil and gas property include, but not limited to, the entity's wells and related equipment and facilities.

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Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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