Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Segment Reporting Information
Midstream Services — Affiliate	$ 93,739		$ 97,269	$ 207,523	$ 201,072
Total Revenues	145,950		170,660	369,995	331,362
Goodwill Impairment	0	$ 109,700	0	109,734	0
Income (Loss) Before Income Taxes	50,732		56,494	13,365	125,594
Additions to Long-Lived Assets	4,997		58,092	52,725	136,293
Additions to Investments	2,627		143,984	228,226	414,587
Total Assets	3,008,347			3,008,347		$ 2,926,082
Gathering Systems
Segment Reporting Information
Midstream Services — Affiliate	83,439		78,902	173,624	155,118
Total Revenues	133,839		149,839	330,111	279,145
Goodwill Impairment				109,734
Income (Loss) Before Income Taxes	58,392		52,668	17,174	106,328
Additions to Long-Lived Assets	4,849		56,739	52,468	134,388
Additions to Investments	0		0	0	0
Total Assets	2,019,477			2,019,477		2,160,026
Fresh Water Delivery
Segment Reporting Information
Midstream Services — Affiliate	10,300		18,367	33,899	45,954
Total Revenues	12,111		20,821	39,884	52,217
Goodwill Impairment				0
Income (Loss) Before Income Taxes	10,336		13,621	32,779	36,830
Additions to Long-Lived Assets	0		1,113	0	1,394
Additions to Investments	0		0	0	0
Total Assets	92,823			92,823		91,840
Investments in Midstream Entities
Segment Reporting Information
Midstream Services — Affiliate	0		0	0	0
Total Revenues	0		0	0	0
Goodwill Impairment				0
Income (Loss) Before Income Taxes	(2,730)		(1,748)	(8,139)	593
Additions to Long-Lived Assets	0		0	0	0
Additions to Investments	2,627		143,984	228,226	414,587
Total Assets	860,817			860,817		660,778
Corporate
Segment Reporting Information
Midstream Services — Affiliate	0		0	0	0
Total Revenues	0		0	0	0
Goodwill Impairment				0
Income (Loss) Before Income Taxes	(15,266)		(8,047)	(28,449)	(18,157)
Additions to Long-Lived Assets	148		240	257	511
Additions to Investments	0		0	0	0
Total Assets	35,230			35,230		$ 13,438
Midstream Services — Third Party
Segment Reporting Information
Services and Sales Revenues - Third Party	22,997		21,609	50,895	45,638
Midstream Services — Third Party | Gathering Systems
Segment Reporting Information
Services and Sales Revenues - Third Party	21,186		19,155	44,910	39,375
Midstream Services — Third Party | Fresh Water Delivery
Segment Reporting Information
Services and Sales Revenues - Third Party	1,811		2,454	5,985	6,263
Midstream Services — Third Party | Investments in Midstream Entities
Segment Reporting Information
Services and Sales Revenues - Third Party	0		0	0	0
Midstream Services — Third Party | Corporate
Segment Reporting Information
Services and Sales Revenues - Third Party	0		0	0	0
Crude Oil Sales — Third Party
Segment Reporting Information
Services and Sales Revenues - Third Party	29,214		51,782	111,577	84,652
Crude Oil Sales — Third Party | Gathering Systems
Segment Reporting Information
Services and Sales Revenues - Third Party	29,214		51,782	111,577	84,652
Crude Oil Sales — Third Party | Fresh Water Delivery
Segment Reporting Information
Services and Sales Revenues - Third Party	0		0	0	0
Crude Oil Sales — Third Party | Investments in Midstream Entities
Segment Reporting Information
Services and Sales Revenues - Third Party	0		0	0	0
Crude Oil Sales — Third Party | Corporate
Segment Reporting Information
Services and Sales Revenues - Third Party	$ 0		$ 0	$ 0	$ 0