Acquisitions and Divestitures	12 Months Ended
Dec. 31, 2014
Business Combinations [Abstract]
Acquisitions and Divestitures	Acquisitions and Divestitures Acquisitions In December 2014, the Company completed the acquisition of certain proved and unproved oil and gas properties in the Eagle Ford Shale in south Texas for approximately $30.5 million, subject to post-closing adjustments. Total net cash consideration paid by the Company as of the closing date was approximately $29.6 million, which reflects the impact of customary purchase price adjustments and acquisition costs. In October 2014, the Company completed the acquisition of certain proved and unproved oil and gas properties in the Eagle Ford Shale in south Texas. Total net cash consideration paid by the Company was approximately $185.2 million, which reflects the purchase price of $210.0 million, adjusted by approximately $17.4 million for consents that the seller was unable to obtain for certain leaseholds prior to closing and approximately $8.0 million for the impact of customary purchase price adjustments and acquisition costs. In addition, the Company also assumed a liability of approximately $1.2 million related to asset retirement obligations of the wells acquired. The Company accounted for these transactions as an asset purchase, whereby the identifiable assets acquired were recorded at cost, with the respective assigned carrying amount based on the relative fair value of the unproved and proved properties at the acquisition date. The fair value measurement of assets acquired was based on inputs that are not observable in the market and therefore represent Level 3 inputs. The fair value of oil and gas properties were measured using discounted future cash flows. The discount factor used was based on rates utilized by market participants that are commensurate with the risks inherent in the development and production of the underlying natural gas and oil. Significant inputs to the valuation of oil and gas properties include (i) reserves, including risk adjustments for probable and possible reserves; (ii) production rates based on the Company's experience with similar properties in which it operates; (iii) estimated future operating and development costs; (iv) future commodity prices; (v) future cash flows; and (vi) a market-based weighted average cost of capital rate of 10%. Divestitures The Company recognized an aggregate net gain on sale of assets of $17.1 million, $21.4 million and $50.6 million for the years ended December 31, 2014, 2013 and 2012, respectively. In October 2014, the Company completed the divestiture of certain proved and unproved oil and gas properties in east Texas to a third party for approximately $44.3 million and recognized a $19.9 million gain on sale of assets. In December 2013, the Company sold certain proved and unproved oil and gas properties located in the Oklahoma and Texas panhandles to Chaparral Energy, L.L.C. for approximately $160.0 million and recognized a $19.4 million gain on sale of assets. The Company also sold certain proved and unproved oil and gas properties located in Oklahoma, Texas and Kansas to a third party for approximately $123.4 million and recognized a $17.5 million loss on sale of assets. In 2013, the Company sold various other proved and unproved oil and gas properties for approximately $44.3 million and recognized an aggregate net gain of $19.5 million. In December 2012, the Company sold certain proved oil and gas properties located in south Texas to a private company for $29.9 million, and recognized an $18.2 million loss on sale of assets. In June 2012, the Company sold a 35% non-operated working interest associated with certain of its Pearsall Shale undeveloped leaseholds in south Texas to a wholly owned subsidiary of Osaka Gas Co., Ltd. (Osaka) for total consideration of approximately $250.0 million. The Company received $125.0 million in cash proceeds and Osaka agreed to fund 85% of the Company's share of future drilling and completion costs associated with these leaseholds until it has paid approximately $125.0 million in accordance with a joint development agreement entered into at closing. The Company recognized a $67.0 million gain on sale of assets associated with this sale. The drilling and completion carry was fully satisfied in 2013. In 2012, the Company sold various other unproved oil and gas properties and other assets for approximately $14.4 million and recognized an aggregate net gain of $1.8 million.

Acquisitions and Divestitures

Acquisitions

In December 2014, the Company completed the acquisition of certain proved and unproved oil and gas properties in the Eagle Ford Shale in south Texas for approximately $30.5 million, subject to post-closing adjustments. Total net cash consideration paid by the Company as of the closing date was approximately $29.6 million, which reflects the impact of customary purchase price adjustments and acquisition costs.

In October 2014, the Company completed the acquisition of certain proved and unproved oil and gas properties in the Eagle Ford Shale in south Texas. Total net cash consideration paid by the Company was approximately $185.2 million, which reflects the purchase price of $210.0 million, adjusted by approximately $17.4 million for consents that the seller was unable to obtain for certain leaseholds prior to closing and approximately $8.0 million for the impact of customary purchase price adjustments and acquisition costs. In addition, the Company also assumed a liability of approximately $1.2 million related to asset retirement obligations of the wells acquired.

The Company accounted for these transactions as an asset purchase, whereby the identifiable assets acquired were recorded at cost, with the respective assigned carrying amount based on the relative fair value of the unproved and proved properties at the acquisition date. The fair value measurement of assets acquired was based on inputs that are not observable in the market and therefore represent Level 3 inputs. The fair value of oil and gas properties were measured using discounted future cash flows. The discount factor used was based on rates utilized by market participants that are commensurate with the risks inherent in the development and production of the underlying natural gas and oil. Significant inputs to the valuation of oil and gas properties include (i) reserves, including risk adjustments for probable and possible reserves; (ii) production rates based on the Company's experience with similar properties in which it operates; (iii) estimated future operating and development costs; (iv) future commodity prices; (v) future cash flows; and (vi) a market-based weighted average cost of capital rate of 10%.

Divestitures

The Company recognized an aggregate net gain on sale of assets of $17.1 million, $21.4 million and $50.6 million for the years ended December 31, 2014, 2013 and 2012, respectively.

In October 2014, the Company completed the divestiture of certain proved and unproved oil and gas properties in east

Texas to a third party for approximately $44.3 million and recognized a $19.9 million gain on sale of assets.

In December 2013, the Company sold certain proved and unproved oil and gas properties located in the Oklahoma and Texas panhandles to Chaparral Energy, L.L.C. for approximately $160.0 million and recognized a $19.4 million gain on sale of assets. The Company also sold certain proved and unproved oil and gas properties located in Oklahoma, Texas and Kansas to a third party for approximately $123.4 million and recognized a $17.5 million loss on sale of assets.

In 2013, the Company sold various other proved and unproved oil and gas properties for approximately $44.3 million and recognized an aggregate net gain of $19.5 million.

In December 2012, the Company sold certain proved oil and gas properties located in south Texas to a private company for $29.9 million, and recognized an $18.2 million loss on sale of assets.

In June 2012, the Company sold a 35% non-operated working interest associated with certain of its Pearsall Shale undeveloped leaseholds in south Texas to a wholly owned subsidiary of Osaka Gas Co., Ltd. (Osaka) for total consideration of approximately $250.0 million. The Company received $125.0 million in cash proceeds and Osaka agreed to fund 85% of the Company's share of future drilling and completion costs associated with these leaseholds until it has paid approximately $125.0 million in accordance with a joint development agreement entered into at closing. The Company recognized a $67.0 million gain on sale of assets associated with this sale. The drilling and completion carry was fully satisfied in 2013.

In 2012, the Company sold various other unproved oil and gas properties and other assets for approximately $14.4 million and recognized an aggregate net gain of $1.8 million.