Business Segment Information (Narrative) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2026 USD ($) segment	Sep. 30, 2025 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment	3
Segment Reporting Information [Line Items]
Capital Expenditures	$ 97,844	$ 122,371
Costs incurred, percentage	1	1
Operating Segments
Segment Reporting Information [Line Items]
Capital Expenditures	$ 95,521	$ 121,381
Operating Segments | Offshore pipeline transportation
Segment Reporting Information [Line Items]
Capital Expenditures	24,713	75,332
Operating Segments | Marine transportation
Segment Reporting Information [Line Items]
Capital Expenditures	59,883	40,393
Operating Segments | Onshore transportation and services
Segment Reporting Information [Line Items]
Capital Expenditures	10,925	5,656
Other
Segment Reporting Information [Line Items]
Capital Expenditures	$ 2,323	$ 990