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Fair Value Measurements (Details) - USD ($) $ in Thousands | 6 Months Ended |
--- | --- | ---
Jun. 30, 2015 | Jun. 30, 2014 | Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Asset retirement obligation capitalized | $ 4,077 | $ 3,613 |
Mammoth Energy Partners LP [Member] |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Equity investment |  |  | $ 143,500
Level 1 [Member] |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Derivative Instruments | 103,221 |  |
Derivative Instruments | 3,690 |  |
Level 2 [Member] |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Derivative Instruments | 0 |  |
Derivative Instruments | 0 |  |
Level 3 [Member] |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Derivative Instruments | 0 |  |
Derivative Instruments | 0 |  |
Asset retirement obligation capitalized | $ 4,100 |  |
Level 3 [Member] | Mammoth Energy Partners LP [Member] |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Equity investment |  |  | $ 143,500

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