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Petroleum and Natural Gas Sales
 12 Months Ended
Dec. 31, 2017
Revenue [abstract]  
Petroleum and Natural Gas Sales
PETROLEUM AND NATURAL GAS SALES
(000s)
 
2017

 
2016

Petroleum and natural gas sales
 
$
252,591

 
$
122,360

Less: Royalties
 
104,127

 
59,226

Petroleum and natural gas sales, net of royalties
 
$
148,464

 
$
63,134