Segments - Total Assets for Reportable Segments (Detail) - USD ($) $ in Millions		Jun. 30, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Total assets		$ 3,598.7	$ 3,485.6
Interest and Other
Segment Reporting Information [Line Items]
Total assets		200.5	127.7
Gathering Opco | Operating Segments
Segment Reporting Information [Line Items]
Total assets		1,988.0	1,927.0
Processing and Storage | Operating Segments
Segment Reporting Information [Line Items]
Total assets	[1]	1,133.1	1,149.5
Terminaling and Export | Operating Segments
Segment Reporting Information [Line Items]
Total assets		$ 277.1	$ 281.4

[1] Includes investment in equity investees of $96.9 million as of June 30, 2022 and $101.6 million as of December 31, 2021.