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Properties and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($)
$ in Thousands
Sep. 30, 2017
Dec. 31, 2016
Property, Plant and Equipment [Abstract]    
Proved oil and gas properties $ 6,967,205 $ 7,437,604
Unproved oil and gas properties 287,147 260,543
Gathering and pipeline systems 1,451 187,846
Land, building and other equipment 88,371 84,462
Properties and equipment, gross, total 7,344,174 7,970,455
Accumulated depreciation, depletion and amortization (3,109,402) (3,720,330)
Properties and equipment, net $ 4,234,772 $ 4,250,125