Natural Gas Producing Activities (Unaudited) - Schedule of the Entity's Proved and Unproved Reserves (Details)	12 Months Ended
	Dec. 31, 2016 MBbls MMcf	Dec. 31, 2015 MBbls MMcf	Dec. 31, 2014 MBbls MMcf
Proved developed and undeveloped reserves:
Beginning of year	9,976,597	10,738,948	8,348,269
Revision of previous estimates	(472,285)	(2,194,675)	(301,351)
Purchase	2,395,776	0	102,713
Sale	0	(61)	(198,657)
Extensions, discoveries and other additions	2,384,682	2,051,071	3,276,054
Production	(776,363)	(618,686)	(488,080)
End of year	13,508,407	9,976,597	10,738,948
Proved developed reserves:
Beginning of year	6,279,557	4,826,387	3,985,687
End of year	6,842,958	6,279,557	4,826,387
Proved undeveloped reserves:
Beginning of year	3,697,040	5,912,561	4,362,582
End of year	6,665,449	3,697,040	5,912,561
Natural Gas
Proved developed and undeveloped reserves:
Beginning of year	9,110,311	9,775,954	7,561,561
Revision of previous estimates	(607,171)	(2,059,531)	(228,085)
Purchase	2,288,166	0	44,867
Sale	0	(61)	(198,531)
Extensions, discoveries and other additions	2,241,528	1,955,935	3,040,938
Production	(700,967)	(561,986)	(444,796)
End of year	12,331,867	9,110,311	9,775,954
Proved developed reserves:
Beginning of year	5,652,989	4,257,377	3,567,313
End of year	6,074,958	5,652,989	4,257,377
Proved undeveloped reserves:
Beginning of year	3,457,322	5,518,577	3,994,248
End of year	6,256,909	3,457,322	5,518,577
Cubic feet per thousand barrel (in mmcf)	6
Oil
Proved developed and undeveloped reserves:
Beginning of year | MBbls	5,900	5,005	3,956
Revision of previous estimates | MBbls	1,159	1,219	(905)
Purchase | MBbls	3	0	2,165
Sale | MBbls	0	0	(3)
Extensions, discoveries and other additions | MBbls	62	419	241
Production | MBbls	(729)	(743)	(449)
End of year | MBbls	6,395	5,900	5,005
Proved developed reserves:
Beginning of year | MBbls	5,900	5,005	3,892
End of year | MBbls	6,395	5,900	5,005
Proved undeveloped reserves:
Beginning of year | MBbls	0	0	64
End of year | MBbls	0	0	0
Cubic feet per thousand barrel (in mmcf)	6
Natural Gas Liquids
Proved developed and undeveloped reserves:
Beginning of year | MBbls	138,481	155,494	127,162
Revision of previous estimates | MBbls	21,322	(23,743)	(11,306)
Purchase | MBbls	17,932	0	7,476
Sale | MBbls	0	0	(18)
Extensions, discoveries and other additions | MBbls	23,797	15,437	38,945
Production | MBbls	(11,837)	(8,707)	(6,765)
End of year | MBbls	189,695	138,481	155,494
Proved developed reserves:
Beginning of year | MBbls	98,528	89,830	65,837
End of year | MBbls	121,605	98,528	89,830
Proved undeveloped reserves:
Beginning of year | MBbls	39,953	65,664	61,325
End of year | MBbls	68,090	39,953	65,664
Cubic feet per thousand barrel (in mmcf)	6