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Common Stock Options, Restricted Stock And Changes In Capitalization (Details) $ / shares in Units, a in Thousands, $ in Thousands |  |  |  |  | 12 Months Ended | 132 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Jun. 12, 2015 USD ($) shares | Apr. 21, 2015 USD ($) shares | Nov. 13, 2013 USD ($) $ / shares shares | Feb. 15, 2013 USD ($) $ / shares shares | Dec. 31, 2015 USD ($) $ / shares shares | Dec. 31, 2014 USD ($) $ / shares shares | Dec. 31, 2013 USD ($) shares | Dec. 31, 2015 $ / shares shares | Feb. 28, 2014 a | Apr. 19, 2013 shares | Apr. 20, 2006 shares | Apr. 19, 2006 shares
Common Stock Options, Restricted Stock, Warrants And Changes In Capitalization [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Granted for purchase of previous Plan's common stock (shares) |  |  |  |  | 0 | 0 | 0 | 0 |  |  |  |
Proceeds from issuance of common stock, net of offering costs and exercise of stock options | $ | $ 479,700 | $ 501,800 |  |  | $ 981,568 | $ 689 | $ 766,495 |  |  |  |  |
Common stock, par value (usd per share) | $ / shares |  |  |  |  | $ 0.01 | $ 0.01 |  | $ 0.01 |  |  |  |
Preferred stock dividend rate, percentage |  |  |  |  | 12.00% | 12.00% |  |  |  |  |  |
Utica Shale |  |  |  |  |  |  |  |  |  |  |  |
Common Stock Options, Restricted Stock, Warrants And Changes In Capitalization [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Gas and oil acreage, undeveloped, net | a |  |  |  |  |  |  |  |  | 8 |  |  |
Common Stock |  |  |  |  |  |  |  |  |  |  |  |
Common Stock Options, Restricted Stock, Warrants And Changes In Capitalization [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Issuance of common stock in public offering (shares) | 11,500,000 | 10,925,000 |  |  | 22,425,000 |  | 17,287,500 |  |  |  |  |
Common Stock | Public Offering |  |  |  |  |  |  |  |  |  |  |  |
Common Stock Options, Restricted Stock, Warrants And Changes In Capitalization [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Issuance of common stock in public offering (shares) |  |  | 7,475,000 | 8,912,500 |  |  |  |  |  |  |  |
Share price (usd per share) | $ / shares |  |  | $ 56.75 | $ 38.00 |  |  |  |  |  |  |  |
Proceeds from issuance of common stock, net of offering costs and exercise of stock options | $ |  |  | $ 408,000 | $ 325,800 |  |  |  |  |  |  |  |
2005 Stock Incentive Plan | Restricted Stock |  |  |  |  |  |  |  |  |  |  |  |
Common Stock Options, Restricted Stock, Warrants And Changes In Capitalization [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Granted for purchase of previous Plan's common stock (shares) |  |  |  |  | 1,143,217 |  |  |  |  |  |  |
2005 Stock Incentive Plan | Common Stock |  |  |  |  |  |  |  |  |  |  |  |
Common Stock Options, Restricted Stock, Warrants And Changes In Capitalization [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Available for grant (shares) |  |  |  |  | 610,966 |  |  | 610,966 |  |  | 3,000,000 | 1,904,606
Granted for purchase of previous Plan's common stock (shares) |  |  |  |  | 997,269 |  |  |  |  |  |  |
1999 Stock Option Plan | Common Stock |  |  |  |  |  |  |  |  |  |  |  |
Common Stock Options, Restricted Stock, Warrants And Changes In Capitalization [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Granted to employees under previous plan (shares) |  |  |  |  |  | 627,337 |  |  |  | 627,337 |  |
2013 Restated Stock Incentive Plan | Common Stock |  |  |  |  |  |  |  |  |  |  |  |
Common Stock Options, Restricted Stock, Warrants And Changes In Capitalization [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Available for grant (shares) |  |  |  |  |  |  |  |  |  | 7,500,000 | 3,000,000 |

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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 Regulation S-K (SK) -Number 229 -Section 1208 -Paragraph (b) + Details
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