Segment Information - Summarized Financial Results by Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Midstream Services — Affiliate									$ 417,835	$ 338,747	$ 271,269
Services and Sales Revenues - Third Party											18,353
Total Revenues	$ 190,765	$ 181,674	$ 170,660	$ 160,702	$ 151,150	$ 154,925	$ 139,435	$ 113,225	703,801	558,735	289,622
Cost of Crude Oil Sales									181,390	136,368	0
Direct Operating Expense									116,675	95,852	67,832
Depreciation and Amortization									96,981	79,568	22,990
Income (Loss) Before Income Taxes	52,190	$ 71,698	$ 56,494	$ 69,100	64,971	$ 57,160	$ 54,408	$ 48,181	249,482	224,720	188,739
Intangible Assets, Net	277,900				310,202				277,900	310,202
Goodwill	109,734				109,734				109,734	109,734
Total Assets	2,926,082				2,192,178				2,926,082	2,192,178
Additions to Long-Lived Assets									876,789	762,426
Midstream Services — Third Party
Segment Reporting Information [Line Items]
Services and Sales Revenues - Third Party									96,194	78,498	18,353
Crude Oil Sales — Third Party
Segment Reporting Information [Line Items]
Services and Sales Revenues - Third Party									189,772	141,490	0
Operating Segments | Gathering Systems
Segment Reporting Information [Line Items]
Midstream Services — Affiliate									340,269	269,481	195,409
Services and Sales Revenues - Third Party											7,444
Total Revenues									613,644	470,124	202,853
Cost of Crude Oil Sales									181,390	136,368
Direct Operating Expense									95,743	79,848	50,963
Depreciation and Amortization									94,455	77,309	20,724
Income (Loss) Before Income Taxes									242,545	172,826	129,770
Intangible Assets, Net	277,900				310,202				277,900	310,202
Goodwill	109,734				109,734				109,734	109,734
Total Assets	2,160,026				1,998,361				2,160,026	1,998,361
Additions to Long-Lived Assets									257,066	738,427
Operating Segments | Gathering Systems | Midstream Services — Third Party
Segment Reporting Information [Line Items]
Services and Sales Revenues - Third Party									83,603	59,153
Operating Segments | Gathering Systems | Crude Oil Sales — Third Party
Segment Reporting Information [Line Items]
Services and Sales Revenues - Third Party									189,772	141,490
Operating Segments | Fresh Water Delivery
Segment Reporting Information [Line Items]
Midstream Services — Affiliate									77,566	69,266	75,860
Services and Sales Revenues - Third Party											10,909
Total Revenues									90,157	88,611	86,769
Cost of Crude Oil Sales									0	0
Direct Operating Expense									18,650	14,269	16,011
Depreciation and Amortization									2,526	2,259	2,266
Income (Loss) Before Income Taxes									68,980	72,083	68,492
Intangible Assets, Net	0				0				0	0
Goodwill	0				0				0	0
Total Assets	91,840				96,280				91,840	96,280
Additions to Long-Lived Assets									7,330	23,018
Operating Segments | Fresh Water Delivery | Midstream Services — Third Party
Segment Reporting Information [Line Items]
Services and Sales Revenues - Third Party									12,591	19,345
Operating Segments | Fresh Water Delivery | Crude Oil Sales — Third Party
Segment Reporting Information [Line Items]
Services and Sales Revenues - Third Party									0	0
Operating Segments | Investments and Other
Segment Reporting Information [Line Items]
Midstream Services — Affiliate									0	0	0
Services and Sales Revenues - Third Party											0
Total Revenues									0	0	0
Cost of Crude Oil Sales									0	0
Direct Operating Expense									0	0	0
Depreciation and Amortization									0	0	0
Income (Loss) Before Income Taxes									(17,748)	16,289	6,344
Intangible Assets, Net	0				0				0	0
Goodwill	0				0				0	0
Total Assets	660,778				82,317				660,778	82,317
Additions to Long-Lived Assets									611,325	426
Operating Segments | Investments and Other | Midstream Services — Third Party
Segment Reporting Information [Line Items]
Services and Sales Revenues - Third Party									0	0
Operating Segments | Investments and Other | Crude Oil Sales — Third Party
Segment Reporting Information [Line Items]
Services and Sales Revenues - Third Party									0	0
Corporate
Segment Reporting Information [Line Items]
Midstream Services — Affiliate									0	0	0
Services and Sales Revenues - Third Party											0
Total Revenues									0	0	0
Cost of Crude Oil Sales									0	0
Direct Operating Expense									2,282	1,735	858
Depreciation and Amortization									0	0	0
Income (Loss) Before Income Taxes									(44,295)	(36,478)	$ (15,867)
Intangible Assets, Net	0				0				0	0
Goodwill	0				0				0	0
Total Assets	$ 13,438				$ 15,220				13,438	15,220
Additions to Long-Lived Assets									1,068	555
Corporate | Midstream Services — Third Party
Segment Reporting Information [Line Items]
Services and Sales Revenues - Third Party									0	0
Corporate | Crude Oil Sales — Third Party
Segment Reporting Information [Line Items]
Services and Sales Revenues - Third Party									$ 0	$ 0