Segments - Financial Data for Each Reportable Segment (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Revenues and other income	$ 414.2	$ 365.5	$ 796.2	$ 721.1
Operating and maintenance expenses (exclusive of depreciation shown separately below)	94.1	87.5	179.7	165.6
Depreciation expense	51.8	50.5	103.3	100.3
General and administrative expenses	8.1	5.2	15.6	10.9
Income from equity investments	4.0	3.7	7.4	6.4
Interest expense, net	55.4	49.7	111.8	98.2
Income tax expense	29.1	16.0	52.1	30.3
Adjusted EBITDA	318.8	278.2	613.6	554.9
Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	414.2	365.5	796.2	721.1
Operating and maintenance expenses (exclusive of depreciation shown separately below)	94.1	87.5	179.7	165.6
Depreciation expense	51.8	50.5	103.3	100.3
General and administrative expenses	5.3	3.5	10.3	7.0
Income from equity investments	4.0	3.7	7.4	6.4
Adjusted EBITDA	318.8	278.2	613.6	554.9
Capital expenditures	70.0	72.7	120.1	107.9
Interest and Other
Segment Reporting Information [Line Items]
General and administrative expenses	2.8	1.7	5.3	3.9
Interest expense, net	55.4	49.7	111.8	98.2
Income tax expense	29.1	16.0	52.1	30.3
Gathering Opco | Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	222.4	195.5	426.0	383.6
Operating and maintenance expenses (exclusive of depreciation shown separately below)	54.7	50.8	105.1	97.1
Depreciation expense	32.7	31.5	65.1	62.3
General and administrative expenses	3.2	2.3	6.2	4.4
Adjusted EBITDA	164.5	142.4	314.7	282.1
Capital expenditures	65.1	69.5	112.8	101.2
Processing and Storage | Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	157.9	139.5	305.7	278.6
Operating and maintenance expenses (exclusive of depreciation shown separately below)	30.6	27.3	58.3	52.5
Depreciation expense	14.8	14.6	29.5	29.3
General and administrative expenses	1.9	1.0	3.6	2.2
Income from equity investments	4.0	3.7	7.4	6.4
Adjusted EBITDA	129.4	114.9	251.2	230.3
Capital expenditures	4.8	3.2	7.2	6.6
Terminaling and Export | Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	33.9	30.5	64.5	58.9
Operating and maintenance expenses (exclusive of depreciation shown separately below)	8.8	9.4	16.3	16.0
Depreciation expense	4.3	4.4	8.7	8.7
General and administrative expenses	0.2	0.2	0.5	0.4
Adjusted EBITDA	24.9	$ 20.9	47.7	42.5
Capital expenditures	$ 0.1		$ 0.1	$ 0.1