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Property and Equipment (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Property, Plant and Equipment [Line Items]    
Property and equipment $ 833,203 $ 829,127
Accumulated depreciation, depletion, amortization and impairment (696,892) (604,289)
Net Property and Equipment 136,311 224,838
Oil and Gas Properties [Member]    
Property, Plant and Equipment [Line Items]    
Property and equipment 794,634 787,683
Equipment and Other [Member]    
Property, Plant and Equipment [Line Items]    
Property and equipment $ 15,227 18,866
Equipment and Other [Member] | Minimum [Member]    
Property, Plant and Equipment [Line Items]    
Estimated useful life 3 years  
Equipment and Other [Member] | Maximum [Member]    
Property, Plant and Equipment [Line Items]    
Estimated useful life 39 years  
Drilling Rig [Member]    
Property, Plant and Equipment [Line Items]    
Estimated useful life 15 years  
Property and equipment $ 23,342 $ 22,578