Business Segment Information (Schedule of Total Assets by Reportable Segment) (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Total consolidated assets	$ 7,058,631	$ 7,018,778
Operating Segments | Offshore pipeline transportation
Segment Reporting Information [Line Items]
Total consolidated assets	2,699,539	2,580,032
Operating Segments | Soda and sulfur services
Segment Reporting Information [Line Items]
Total consolidated assets	2,576,160	2,705,350
Operating Segments | Marine transportation
Segment Reporting Information [Line Items]
Total consolidated assets	642,190	645,020
Operating Segments | Onshore facilities and transportation
Segment Reporting Information [Line Items]
Total consolidated assets	1,059,182	1,019,113
Other assets
Segment Reporting Information [Line Items]
Total consolidated assets	$ 81,560	$ 69,263