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Oil and Gas Properties
 12 Months Ended
Dec. 31, 2017
Extractive Industries [Abstract]  
Oil and Gas Properties

6. Oil and Gas Properties

A summary of oil and gas properties follows:

 

 

 

December 31,

 

In thousands

 

2017

 

 

2016

 

Proved properties and equipment

 

$

750,226

 

 

$

538,695

 

Unproved properties

 

 

78,655

 

 

 

72,584

 

Less accumulated depletion and impairment

 

 

(257,718

)

 

 

(172,051

)

Total oil and gas properties

 

$

571,163

 

 

$

439,228