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Common Stock Options, Warrants And Changes In Capitalization (Details) (USD $) In Thousands, except Share data, unless otherwise specified | 6 Months Ended | 0 Months Ended |  |  | 0 Months Ended
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Jun. 30, 2013 | Jun. 30, 2012 | Feb. 15, 2013 Utica Shale [Member] acre | Dec. 24, 2012 Utica Shale [Member] acre | Dec. 19, 2012 Utica Shale [Member] acre | Dec. 17, 2012 Utica Shale [Member] acre | Feb. 15, 2013 Common Stock [Member] Public Offering [Member] | Jan. 07, 2013 Common Stock [Member] Public Offering [Member] | Dec. 24, 2012 Common Stock [Member] Public Offering [Member]
Common Stock Options, Restricted Stock, Warrants And Changes In Capitalization [Line Items] |  |  |  |  |  |  |  |  |
Issuance of common stock in public offering (shares) |  |  |  |  |  |  | 8,912,500 |  | 11,750,000
Stock option, portion available to underwriters (shares) |  |  |  |  |  |  |  |  | 1,650,000
Stock option, portion attributable to underwriters (shares) |  |  |  |  |  |  |  | 900,000 | 750,000
Share price (usd per share) |  |  |  |  |  |  | $ 38.00 |  | $ 38.00
Proceeds from issuance of common stock, net of offering costs | $ 359,040 |  | $ 325,800 | $ 460,700 |  |  | $ 325,800 |  | $ 460,700
Gas and oil acreage, undeveloped, net |  |  | 22,000 | 37,000 | 7,000 | 30,000 |  |  |

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- Definition Fractional interest owned based on working interests or other economic arrangements of lease area 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 area contains proved reserves. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Industry Guide -Number 2 -Paragraph 5 + Details
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