Business Segment Information - Summarized Financial Information of Segments (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues from non-affiliates	$ 546,448	$ 304,748	$ 1,469,001	$ 843,955
Operating income	179,045	32,394	49,356	57,865
Other income (expense)	(88,040)	(92,304)	(371,113)	(59,006)
Income (loss) before income taxes	91,005	(59,910)	(321,757)	(1,141)
Property, plant and equipment, net	6,900,137		6,900,137		$ 6,173,486
Total assets	7,416,431		7,416,431		6,615,130
Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	497,161	269,843	1,328,994	761,450
Midstream Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	75,770	47,660	212,758	125,613
Well Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	56,439	47,163	161,242	101,594
Operating Segments [Member] \| Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	497,161	269,843	1,328,994	761,450
Operating income	146,969	3,484	(53,159)	(12,972)
Other income (expense)	(87,594)	(92,319)	(370,311)	(59,027)
Income (loss) before income taxes	59,375	(88,835)	(423,470)	(71,999)
Property, plant and equipment, net	6,227,767		6,227,767		5,663,323
Total assets	6,675,626		6,675,626		6,050,255
Operating Segments [Member] \| Midstream Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	33,025	18,767	93,663	48,939
Operating income	31,326	25,194	101,457	69,059
Other income (expense)	(367)	(15)	(703)	(13)
Income (loss) before income taxes	30,959	25,179	100,754	69,046
Property, plant and equipment, net	841,797		841,797		649,923
Total assets	867,226		867,226		663,614
Operating Segments [Member] \| Well Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	16,262	16,138	46,344	33,566
Operating income	9,237	10,802	25,415	9,161
Other income (expense)	(79)	30	(99)	34
Income (loss) before income taxes	9,158	10,832	25,316	9,195
Property, plant and equipment, net	41,468		41,468		46,779
Total assets	49,285		49,285		52,800
Segment Reconciling Items [Member] \| Exploration and Production [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	0	0	0	0
Segment Reconciling Items [Member] \| Midstream Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	42,745	28,893	119,095	76,674
Segment Reconciling Items [Member] \| Well Services [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	40,177	31,025	114,898	68,028
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues from non-affiliates	(82,922)	(59,918)	(233,993)	(144,702)
Operating income	(8,487)	(7,086)	(24,357)	(7,383)
Other income (expense)	0	0	0	0
Income (loss) before income taxes	(8,487)	$ (7,086)	(24,357)	$ (7,383)
Property, plant and equipment, net	(210,895)		(210,895)		(186,539)
Total assets	$ (175,706)		$ (175,706)		$ (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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