Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total Midstream Services — Affiliate									$ 224,401	$ 160,724	$ 87,837
Midstream Services — Third Party									14,880	0	0
Total Revenues	$ 68,073	$ 63,111	$ 57,783	$ 50,314	$ 48,465	$ 47,166	$ 32,970	$ 32,123	239,281	160,724	87,837
Direct Operating Expense									54,007	29,107	16,933
Depreciation and Amortization									12,953	9,066	6,891
Income (Loss) Before Income Taxes	46,240	$ 43,789	$ 39,107	$ 34,520	35,191	$ 33,472	$ 23,307	$ 21,820	163,656	113,790	61,268
Total Assets	829,758				369,359				829,758	369,359	305,318
Additions to Long-Lived Assets									390,326	32,584	62,136
Gathering Systems
Segment Reporting Information [Line Items]
Total Midstream Services — Affiliate									148,541	100,723	60,740
Midstream Services — Third Party									3,971
Total Revenues									152,512
Direct Operating Expense									37,138	14,443	13,806
Depreciation and Amortization									10,687	7,361	5,288
Income (Loss) Before Income Taxes									104,687	78,919	41,646
Total Assets	593,590				224,861				593,590	224,861	201,744
Additions to Long-Lived Assets									373,857	30,020	50,858
Fresh Water Delivery
Segment Reporting Information [Line Items]
Total Midstream Services — Affiliate									75,860	60,001	27,097
Midstream Services — Third Party									10,909
Total Revenues									86,769
Direct Operating Expense									16,011	14,390	2,595
Depreciation and Amortization									2,266	1,705	1,603
Income (Loss) Before Income Taxes									68,492	43,906	22,899
Total Assets	68,178				54,542				68,178	54,542	49,189
Additions to Long-Lived Assets									16,469	2,564	11,278
Investments and Other
Segment Reporting Information [Line Items]
Total Midstream Services — Affiliate									0	0	0
Midstream Services — Third Party									0
Total Revenues									0
Direct Operating Expense									858	274	532
Depreciation and Amortization									0	0	0
Income (Loss) Before Income Taxes									(9,523)	(9,035)	(3,277)
Total Assets	$ 167,990				$ 89,956				167,990	89,956	54,385
Additions to Long-Lived Assets									$ 0	$ 0	$ 0