Segments - Financial Data for Each Reportable Segment (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Revenues and other income	$ 382.0	$ 355.6
Operating and maintenance expenses (exclusive of depreciation shown separately below)	85.6	78.1
Depreciation expense	51.5	49.8
General and administrative expenses	7.5	5.7
Income from equity investments	3.4	2.7
Interest expense, net	56.4	48.5
Income tax expense	23.0	14.3
Adjusted EBITDA	294.8	276.7
Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	382.0	355.6
Operating and maintenance expenses (exclusive of depreciation shown separately below)	85.6	78.1
Depreciation expense	51.5	49.8
General and administrative expenses	5.0	3.5
Income from equity investments	3.4	2.7
Adjusted EBITDA	294.8	276.7
Capital expenditures	50.1	35.2
Interest and Other
Segment Reporting Information [Line Items]
General and administrative expenses	2.5	2.2
Interest expense, net	56.4	48.5
Income tax expense	23.0	14.3
Gathering Opco | Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	203.6	188.1
Operating and maintenance expenses (exclusive of depreciation shown separately below)	50.4	46.3
Depreciation expense	32.4	30.8
General and administrative expenses	3.0	2.1
Adjusted EBITDA	150.2	139.7
Capital expenditures	47.7	31.7
Processing and Storage | Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	147.8	139.1
Operating and maintenance expenses (exclusive of depreciation shown separately below)	27.7	25.2
Depreciation expense	14.7	14.7
General and administrative expenses	1.7	1.2
Income from equity investments	3.4	2.7
Adjusted EBITDA	121.8	115.4
Capital expenditures	2.4	3.4
Terminaling and Export | Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	30.6	28.4
Operating and maintenance expenses (exclusive of depreciation shown separately below)	7.5	6.6
Depreciation expense	4.4	4.3
General and administrative expenses	0.3	0.2
Adjusted EBITDA	$ 22.8	21.6
Capital expenditures		$ 0.1