Commodity Derivatives (Details 3) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Commodity derivative assets:
Commodity derivative asset		$ 3,517
Commodity derivative asset - non-current	147	3,505
Commodity derivative liabilities:
Commodity derivative	1,657
Commodity derivative liability - non-current	318
Gross Recognized Assets/Liabilities [Member]
Commodity derivative assets:
Commodity derivative asset	1,063
Commodity derivative asset - non-current	2,049
Total derivative assets	3,112
Commodity derivative liabilities:
Commodity derivative	2,720
Commodity derivative liability - non-current	2,220
Total derivative liabilities	4,940
Gross Amounts Offset [Member]
Commodity derivative assets:
Commodity derivative asset	(1,063)
Commodity derivative asset - non-current	(1,902)
Total derivative assets	(2,965)
Commodity derivative liabilities:
Commodity derivative	(1,063)
Commodity derivative liability - non-current	(1,902)
Total derivative liabilities	(2,965)
Net Recognized Fair Value Assets/Liabilities [Member]
Commodity derivative assets:
Commodity derivative asset
Commodity derivative asset - non-current	147
Total derivative assets	147
Commodity derivative liabilities:
Commodity derivative	(1,657)
Commodity derivative liability - non-current	(318)
Total derivative liabilities	$ (1,975)

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