Property, Plant, and Equipment - Historical Cost Table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	$ 12,355,671	$ 11,258,773
Less accumulated depreciation	3,290,740	2,848,420
Net property, plant, and equipment	9,064,931	8,410,353
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	9,495	5,298
Gathering Systems – Pipelines [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	$ 5,092,004	4,764,099
Estimated useful life	30 years
Gathering Systems – Compressors [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	$ 1,929,377	1,712,939
Estimated useful life	15 years
Processing Complexes And Treating Facilities [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	$ 3,237,801	2,844,337
Estimated useful life	25 years
Transportation Pipeline And Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	$ 173,572	172,558
Transportation Pipeline And Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	6 years
Transportation Pipeline And Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	45 years
Produced-Water Disposal Systems [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	$ 754,774	629,946
Estimated useful life	20 years
Assets Under Construction [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	$ 486,584	604,265
Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment	$ 672,064	$ 525,331
Other [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Other [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years