Business Segment Information (Schedule of Total Assets by Reportable Segment) (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Total consolidated assets	$ 6,951,302	$ 7,018,778
Operating Segments | Offshore pipeline transportation
Segment Reporting Information [Line Items]
Total consolidated assets	2,653,561	2,580,032
Operating Segments | Soda and sulfur services
Segment Reporting Information [Line Items]
Total consolidated assets	2,616,451	2,705,350
Operating Segments | Marine transportation
Segment Reporting Information [Line Items]
Total consolidated assets	639,386	645,020
Operating Segments | Onshore facilities and transportation
Segment Reporting Information [Line Items]
Total consolidated assets	965,850	1,019,113
Other assets
Segment Reporting Information [Line Items]
Total consolidated assets	$ 76,054	$ 69,263