Business Segment Information - Summarized Financial Information of Segments (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues from non-affiliates	$ 501,337	$ 254,091	$ 922,553	$ 539,207
Total revenues	501,337	254,091	922,553	539,207
Operating income (loss)	(242,674)	5,379	(129,689)	25,471
Other income	(174,628)	13,528	(283,073)	33,298
Income (loss) before income taxes	(417,302)	18,907	(412,762)	58,769
Property, plant and equipment, net	6,757,241		6,757,241		$ 6,173,486
Total assets	7,465,335		7,465,335		6,615,130
Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	450,124	226,724	831,832	491,607
Total revenues	450,124	226,724	831,832	491,607
Midstream Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	32,717	15,566	60,639	30,172
Total revenues	72,427	40,312	136,989	77,953
Well Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	18,496	11,801	30,082	17,428
Total revenues	59,914	33,451	104,803	54,431
Operating Segments [Member] \| Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	450,124	226,724	831,832	491,607
Operating income (loss)	(280,090)	(17,425)	(200,130)	(16,456)
Other income	(174,572)	13,525	(282,717)	33,292
Income (loss) before income taxes	(454,662)	(3,900)	(482,847)	16,836
Property, plant and equipment, net	6,129,083		6,129,083		5,663,323
Total assets	6,767,902		6,767,902		6,050,255
Operating Segments [Member] \| Midstream Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	32,717	15,566	60,639	30,172
Operating income (loss)	37,894	23,103	70,132	43,865
Other income	(79)	3	(336)	2
Income (loss) before income taxes	37,815	23,106	69,796	43,867
Property, plant and equipment, net	786,246		786,246		649,923
Total assets	816,422		816,422		663,614
Operating Segments [Member] \| Well Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	18,496	11,801	30,082	17,428
Operating income (loss)	8,028	1,950	16,178	(1,641)
Other income	23	0	(20)	4
Income (loss) before income taxes	8,051	1,950	16,158	(1,637)
Property, plant and equipment, net	44,319		44,319		46,779
Total assets	48,419		48,419		52,800
Segment Reconciling Items [Member] \| Exploration and Production [Member]
Segment Reporting Information [Line Items]
Total revenues	0	0	0	0
Segment Reconciling Items [Member] \| Midstream Services [Member]
Segment Reporting Information [Line Items]
Total revenues	39,710	24,746	76,350	47,781
Segment Reconciling Items [Member] \| Well Services [Member]
Segment Reporting Information [Line Items]
Total revenues	41,418	21,650	74,721	37,003
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues	(81,128)	(46,396)	(151,071)	(84,784)
Operating income (loss)	(8,506)	(2,249)	(15,869)	(297)
Other income	0	0	0	0
Income (loss) before income taxes	(8,506)	$ (2,249)	(15,869)	$ (297)
Property, plant and equipment, net	(202,407)		(202,407)		(186,539)
Total assets	$ (167,408)		$ (167,408)		$ (151,539)

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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