Segments - Total Assets for Reportable Segments (Detail) - USD ($) $ in Millions		Jun. 30, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Total assets		$ 4,050.1	$ 3,789.5
Interest and Other
Segment Reporting Information [Line Items]
Total assets		608.7	338.1
Gathering Opco | Operating Segments
Segment Reporting Information [Line Items]
Total assets		2,167.3	2,138.6
Processing and Storage | Operating Segments
Segment Reporting Information [Line Items]
Total assets	[1]	1,018.7	1,048.4
Terminaling and Export | Operating Segments
Segment Reporting Information [Line Items]
Total assets		$ 255.4	$ 264.4

[1] Includes investment in equity investees of $89.2 million as of June 30, 2024 and $90.2 million as of December 31, 2023.