Segments - Total Assets for Reportable Segments (Detail) - USD ($) $ in Millions		Sep. 30, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Total assets		$ 3,601.5	$ 3,485.6
Interest and Other
Segment Reporting Information [Line Items]
Total assets		198.7	127.7
Gathering Opco | Operating Segments
Segment Reporting Information [Line Items]
Total assets		2,016.1	1,927.0
Processing and Storage | Operating Segments
Segment Reporting Information [Line Items]
Total assets	[1]	1,112.5	1,149.5
Terminaling and Export | Operating Segments
Segment Reporting Information [Line Items]
Total assets		$ 274.2	$ 281.4

[1] Includes investment in equity investees of $98.3 million as of September 30, 2022 and $101.6 million as of December 31, 2021.