Business Segment Information (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2026 USD ($) segment	Mar. 31, 2025 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment	3
Segment Reporting Information [Line Items]
Capital Expenditures	$ 26,239	$ 49,907
Costs incurred, percentage	1	1
Operating Segments
Segment Reporting Information [Line Items]
Capital Expenditures	$ 25,435	$ 49,480
Operating Segments | Offshore pipeline transportation
Segment Reporting Information [Line Items]
Capital Expenditures	6,295	29,314
Operating Segments | Marine transportation
Segment Reporting Information [Line Items]
Capital Expenditures	13,922	16,990
Operating Segments | Onshore transportation and services
Segment Reporting Information [Line Items]
Capital Expenditures	5,218	3,176
Other
Segment Reporting Information [Line Items]
Capital Expenditures	$ 804	$ 427