v3.26.1
Segments - Financial Data for Each Reportable Segment (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting Information [Line Items]        
Revenues and other income $ 399.0 $ 414.2 $ 789.1 $ 796.2
Operating and maintenance expenses (exclusive of depreciation shown separately below) 85.9 94.1 171.5 179.7
Depreciation expense 54.4 51.8 112.9 103.3
General and administrative expenses 5.5 8.1 13.4 15.6
Income from equity investments 6.1 4.0 9.3 7.4
Interest expense, net 54.5 55.4 109.9 111.8
Income tax expense 31.1 29.1 59.3 52.1
Adjusted EBITDA 315.2 318.8 617.1 613.6
Operating Segments        
Segment Reporting Information [Line Items]        
Revenues and other income 399.0 414.2 789.1 796.2
Operating and maintenance expenses (exclusive of depreciation shown separately below) 85.9 94.1 171.5 179.7
Depreciation expense 54.4 51.8 112.9 103.3
General and administrative expenses 4.0 5.3 9.8 10.3
Income from equity investments 6.1 4.0 9.3 7.4
Interest expense, net 0.0 0.0 0.0 0.0
Income tax expense 0.0 0.0 0.0 0.0
Adjusted EBITDA 315.2 318.8 617.1 613.6
Capital expenditures 30.6 70.0 41.0 120.1
Interest and Other        
Segment Reporting Information [Line Items]        
Revenues and other income 0.0 0.0 0.0 0.0
Operating and maintenance expenses (exclusive of depreciation shown separately below) 0.0 0.0 0.0 0.0
Depreciation expense 0.0 0.0 0.0 0.0
General and administrative expenses 1.5 2.8 3.6 5.3
Income from equity investments 0.0 0.0 0.0 0.0
Interest expense, net 54.5 55.4 109.9 111.8
Income tax expense 31.1 29.1 59.3 52.1
Gathering Opco | Operating Segments        
Segment Reporting Information [Line Items]        
Revenues and other income 209.8 222.4 413.9 426.0
Operating and maintenance expenses (exclusive of depreciation shown separately below) 50.4 54.7 100.1 105.1
Depreciation expense 36.6 32.7 74.3 65.1
General and administrative expenses 2.8 3.2 6.9 6.2
Income from equity investments 0.0 0.0 0.0 0.0
Interest expense, net 0.0 0.0 0.0 0.0
Income tax expense 0.0 0.0 0.0 0.0
Adjusted EBITDA 156.6 164.5 306.9 314.7
Capital expenditures 25.7 65.1 31.5 112.8
Processing and Storage | Operating Segments        
Segment Reporting Information [Line Items]        
Revenues and other income 151.3 157.9 299.7 305.7
Operating and maintenance expenses (exclusive of depreciation shown separately below) 28.0 30.6 57.3 58.3
Depreciation expense 13.4 14.8 29.8 29.5
General and administrative expenses 0.9 1.9 2.3 3.6
Income from equity investments 6.1 4.0 9.3 7.4
Interest expense, net 0.0 0.0 0.0 0.0
Income tax expense 0.0 0.0 0.0 0.0
Adjusted EBITDA 128.5 129.4 249.4 251.2
Capital expenditures 4.9 4.8 9.5 7.2
Terminaling and Export | Operating Segments        
Segment Reporting Information [Line Items]        
Revenues and other income 37.9 33.9 75.5 64.5
Operating and maintenance expenses (exclusive of depreciation shown separately below) 7.5 8.8 14.1 16.3
Depreciation expense 4.4 4.3 8.8 8.7
General and administrative expenses 0.3 0.2 0.6 0.5
Income from equity investments 0.0 0.0 0.0 0.0
Interest expense, net 0.0 0.0 0.0 0.0
Income tax expense 0.0 0.0 0.0 0.0
Adjusted EBITDA 30.1 24.9 60.8 47.7
Capital expenditures $ 0.0 $ 0.1 $ 0.0 $ 0.1