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Acquisitions - Fair Value of Assets Acquired (Details) - American Energy - Utica, LLC - USD ($) $ in Thousands | Jun. 29, 2015 | Jun. 12, 2015
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Business Acquisition [Line Items] |  |
Cash, net of purchase price adjustments | $ 405,000 | $ 405,029
Fair value of net identifiable assets acquired |  | 405,029
Proved |  |
Business Acquisition [Line Items] |  |
Fair value of net identifiable assets acquired |  | 70,804
Unevaluated |  |
Business Acquisition [Line Items] |  |
Fair value of net identifiable assets acquired |  | $ 334,225

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