Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Sales and revenues:
Sales and revenues	$ 790,389	$ (249,198)	$ 1,985,968	$ 471,806
Operating expenses:
Lease operating	16,992	12,043	32,543	23,336
Gathering, compression, processing, and transportation	266,747	206,060	533,576	414,798
Depletion, depreciation, and amortization	201,182	197,362	403,911	388,944
General and administrative expense	64,099	60,102	128,797	116,389
Other operating expenses			262,055	339,463
Total operating expenses	666,646	640,675	1,360,882	1,282,930
Operating income (loss)	123,743	(889,873)	625,086	(811,124)
Equity in earnings of unconsolidated affiliate	3,623	484	5,854	484
Segment assets	15,442,221	13,558,780	15,442,221	13,558,780	$ 14,255,550
Capital expenditures for segment assets			1,195,882	945,390
Exploration and production
Sales and revenues:
Sales and revenues	737,229	(343,394)	1,864,280	274,550
Gathering and compression
Sales and revenues:
Sales and revenues	2,324	3,131	4,863	6,718
Fresh Water Distribution
Sales and revenues:
Sales and revenues	868	163	933	420
Marketing
Sales and revenues:
Sales and revenues	49,968	90,902	115,892	190,118
Operating segments
Sales and revenues:
Sales and revenues	790,389	(249,198)
Operating expenses:
Lease operating	16,992	12,043
Gathering, compression, processing, and transportation	266,747	206,060
Depletion, depreciation, and amortization	201,182	197,362
General and administrative expense	64,099	60,102
Other operating expenses	117,626	165,108
Total operating expenses	666,646	640,675
Operating income (loss)	123,743	(889,873)
Equity in earnings of unconsolidated affiliate	3,623	484	5,854	484
Segment assets	15,442,221	13,558,780	15,442,221	13,558,780
Capital expenditures for segment assets	679,648	435,267
Operating segments | Exploration and production
Sales and revenues:
Sales and revenues	741,140	(339,495)	1,872,631	282,274
Operating expenses:
Lease operating	17,189	12,257	32,931	23,589
Gathering, compression, processing, and transportation	353,216	267,738	700,984	535,183
Depletion, depreciation, and amortization	170,446	173,015	345,415	340,567
General and administrative expense	49,531	47,167	100,587	90,719
Other operating expenses	39,251	37,848	92,869	73,013
Total operating expenses	629,633	538,025	1,272,786	1,063,071
Operating income (loss)	111,507	(877,520)	599,845	(780,797)
Segment assets	13,430,135	11,919,732	13,430,135	11,919,732
Capital expenditures for segment assets	584,832	375,247	1,041,782	825,077
Operating segments | Gathering and compression
Sales and revenues:
Sales and revenues	98,762	71,916	190,421	141,543
Operating expenses:
Gathering, compression, processing, and transportation	9,910	6,997	18,024	14,167
Depletion, depreciation, and amortization	22,494	17,172	42,418	34,240
General and administrative expense	10,705	10,138	20,843	19,473
Other operating expenses	12	450	12	899
Total operating expenses	43,121	34,757	81,297	68,779
Operating income (loss)	55,641	37,159	109,124	72,764
Equity in earnings of unconsolidated affiliate	3,623	484	5,854	484
Segment assets	2,065,899	1,598,826	2,065,899	1,598,826
Capital expenditures for segment assets	88,806	48,614	155,365	97,300
Operating segments | Fresh Water Distribution
Sales and revenues:
Sales and revenues	95,005	64,893	178,115	131,339
Operating expenses:
Lease operating	41,444	34,317	80,066	75,031
Depletion, depreciation, and amortization	8,242	7,175	16,078	14,137
General and administrative expense	4,084	3,168	8,403	6,924
Other operating expenses	4,532	4,294	8,876	8,498
Total operating expenses	58,302	48,954	113,423	104,590
Operating income (loss)	36,703	15,939	64,692	26,749
Segment assets	711,735	569,624	711,735	569,624
Capital expenditures for segment assets	58,497	41,589	95,451	78,625
Operating segments | Marketing
Sales and revenues:
Sales and revenues	49,968	90,902		190,118
Operating expenses:
Other operating expenses	77,421	125,977	167,414	263,910
Total operating expenses	77,421	125,977	167,414	263,910
Operating income (loss)	(27,453)	(35,075)	(51,522)	(73,792)
Segment assets	14,357	23,045	14,357	23,045
Elimination of intersegment transaction
Sales and revenues:
Sales and revenues	(194,486)	(137,414)	(371,091)	(273,468)
Operating expenses:
Lease operating	(41,641)	(34,531)	(80,454)	(75,284)
Gathering, compression, processing, and transportation	(96,379)	(68,675)	(185,432)	(134,552)
General and administrative expense	(221)	(371)	(1,036)	(727)
Other operating expenses	(3,590)	(3,461)	(7,116)	(6,857)
Total operating expenses	(141,831)	(107,038)	(274,038)	(217,420)
Operating income (loss)	(52,655)	(30,376)	(97,053)	(56,048)
Segment assets	(779,905)	(552,447)	(779,905)	(552,447)
Capital expenditures for segment assets	(52,487)	(30,183)	(96,716)	(55,612)
Elimination of intersegment transaction | Exploration and production
Sales and revenues:
Sales and revenues	3,911	3,899	8,351	7,724
Elimination of intersegment transaction | Gathering and compression
Sales and revenues:
Sales and revenues	96,438	68,785	185,558	134,825
Elimination of intersegment transaction | Fresh Water Distribution
Sales and revenues:
Sales and revenues	$ 94,137	$ 64,730	177,182	$ 130,919
Elimination of intersegment transaction | Marketing
Sales and revenues:
Sales and revenues			$ 115,892