Supplementary Information on Oil and Natural Gas Activities (Unaudited) - Schedule of Changes in Estimated Proved and Estimated Proved Developed Reserves (Details)	12 Months Ended
	Dec. 31, 2016 MMBoe MMBbls Bcf	Dec. 31, 2015 MMBoe MMBbls Bcf	Dec. 31, 2014 MMBoe MMBbls Bcf	Dec. 31, 2013 MMBoe MMBbls Bcf
Proved developed and undeveloped energy reserves:
Beginning of the year | MMBoe	6.2	9.0	8.5
Extensions and discoveries | MMBoe			0.5
Revisions of previous estimates | MMBoe	(2.5)	(2.8)
Production | MMBoe	(0.4)
End of the year | MMBoe	3.3	6.2	9.0
Proved developed energy reserves:
Proved developed energy reserves | MMBoe	2.1
Proved undeveloped energy reserves:
Proved undeveloped energy reserves | MMBoe	1.2	6.2	9.0	8.5
Oil (MMBbls)
Proved developed and undeveloped reserves:
Beginning of the year	5.6	8.4	7.9
Extensions and discoveries			0.5
Revisions of previous estimates	(2.2)	(2.8)
Production	(0.4)
End of the year	3.0	5.6	8.4
Proved developed reserves:
Proved developed reserves	1.9
Proved undeveloped reserves:
Proved undeveloped reserves	1.1	5.6	8.4	7.9
Natural Gas (Bcf)
Proved developed and undeveloped reserves:
Beginning of the year | Bcf	1.8	3.7	3.4
Extensions and discoveries | Bcf			0.3
Revisions of previous estimates | Bcf	(0.5)	(1.9)
Production | Bcf	(0.1)
End of the year | Bcf	1.2	1.8	3.7
Proved developed reserves:
Proved developed reserves | Bcf	0.8
Proved undeveloped reserves:
Proved undeveloped reserves | Bcf	0.4	1.8	3.7	3.4
Natural Gas Liquids (MMBbls)
Proved developed and undeveloped reserves:
Beginning of the year	0.3
Revisions of previous estimates	(0.2)	0.3
End of the year	0.1	0.3
Proved developed reserves:
Proved developed reserves	0.1
Proved undeveloped reserves:
Proved undeveloped reserves		0.3