Business Segment Information (Schedule of Total Assets and Total Growth and Maintenance Capital Expenditures by Reportable Segment) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)
Segment Reporting Information [Line Items]
Assets	$ 4,869,720		$ 7,037,692
Assets held for discontinued operations	0		2,207,420
Capital Expenditures	$ 122,371	$ 292,742
Costs incurred, percentage	1	1
Operating Segments
Segment Reporting Information [Line Items]
Assets	$ 4,834,354		4,790,616
Capital Expenditures	121,381	$ 282,082
Operating Segments \| Offshore pipeline transportation
Segment Reporting Information [Line Items]
Assets	2,770,893		2,748,296
Capital Expenditures	75,332	193,875
Operating Segments \| Marine transportation
Segment Reporting Information [Line Items]
Assets	624,419		641,082
Capital Expenditures	40,393	72,266
Operating Segments \| Onshore transportation and services
Segment Reporting Information [Line Items]
Assets	1,439,042		1,401,238
Capital Expenditures	5,656	15,941
Other assets
Segment Reporting Information [Line Items]
Assets	35,366		$ 39,656
Other
Segment Reporting Information [Line Items]
Capital Expenditures	$ 990	$ 10,660