Segments - Total Assets for Reportable Segments (Detail) - USD ($) $ in Millions		Jun. 30, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Total assets		$ 3,659.7	$ 3,588.2
Interest and Other
Segment Reporting Information [Line Items]
Total assets		266.6	191.2
Gathering Opco | Operating Segments
Segment Reporting Information [Line Items]
Total assets		2,053.0	2,022.0
Processing and Storage | Operating Segments
Segment Reporting Information [Line Items]
Total assets	[1]	1,068.1	1,099.2
Terminaling and Export | Operating Segments
Segment Reporting Information [Line Items]
Total assets		$ 272.0	$ 275.8

[1] Includes investment in equity investees of $92.8 million as of June 30, 2023 and $93.9 million as of December 31, 2022.