Business Segment Information (Schedule of Total Assets and Total Growth and Maintenance Capital Expenditures by Reportable Segment) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2026 USD ($)	Mar. 31, 2025 USD ($)	Dec. 31, 2025 USD ($)
Segment Reporting Information [Line Items]
Assets	$ 4,836,714		$ 4,860,703
Capital Expenditures	$ 26,239	$ 49,907
Costs incurred, percentage	1	1
Operating Segments
Segment Reporting Information [Line Items]
Assets	$ 4,796,084		4,827,040
Capital Expenditures	25,435	$ 49,480
Operating Segments | Offshore pipeline transportation
Segment Reporting Information [Line Items]
Assets	2,722,655		2,755,595
Capital Expenditures	6,295	29,314
Operating Segments | Marine transportation
Segment Reporting Information [Line Items]
Assets	616,456		618,474
Capital Expenditures	13,922	16,990
Operating Segments | Onshore transportation and services
Segment Reporting Information [Line Items]
Assets	1,456,973		1,452,971
Capital Expenditures	5,218	3,176
Other assets
Segment Reporting Information [Line Items]
Assets	40,630		$ 33,663
Other
Segment Reporting Information [Line Items]
Capital Expenditures	$ 804	$ 427