Supplemental Disclosures About Natural Gas Producing Activities - Natural Gas & Condensate Reserve Quantity Information (Details) MMcf in Thousands, MBbls in Thousands	12 Months Ended
	Dec. 31, 2018 Bcf MBbls MMcf	Dec. 31, 2017 Bcf MBbls MMcf	Dec. 31, 2016 MBbls MMcf
Proved Developed and Undeveloped Reserves [Roll Forward]
Extensions, discoveries and other additions | Bcf	22
Purchases of reserves-in-place | Bcf		327
Gas
Proved Developed and Undeveloped Reserves [Roll Forward]
Proved reserves, beginning balance	327,118	0
Extensions, discoveries and other additions	22,481	0
Revisions of previous estimates	(84,061)	0
Production	(1,399)	(190)
Sale of reserves-in-place	0	0
Purchases of reserves-in-place	715	327,308
Proved reserves, ending balance	264,854	327,118
Proved developed reserves:	17,522	5,720	0
Proved undeveloped reserves:	247,332	321,398	0
Condensate
Proved Developed and Undeveloped Reserves [Roll Forward]
Proved reserves, beginning balance | MBbls	10	0
Extensions, discoveries and other additions | MBbls	0	0
Revisions of previous estimates | MBbls	(2)	0
Production | MBbls	(1)	0
Sale of reserves-in-place | MBbls	0	0
Purchases of reserves-in-place | MBbls	0	10
Proved reserves, ending balance | MBbls	7	10
Proved developed reserves: | MBbls	7	10	0
Proved undeveloped reserves: | MBbls	0	0	0
Gas Equivalent
Proved Developed and Undeveloped Reserves [Roll Forward]
Proved reserves, beginning balance	327,180	0
Extensions, discoveries and other additions	22,481	0
Revisions of previous estimates	(84,072)	0
Production	(1,405)	(191)
Sale of reserves-in-place	0	0
Purchases of reserves-in-place	715	327,371
Proved reserves, ending balance	264,899	327,180
Proved developed reserves:	17,567	5,782	0
Proved undeveloped reserves:	247,332	321,398	0