Business Segment Information (Schedule of Total Assets by Reportable Segment) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Total consolidated assets	$ 6,945,258	$ 7,018,778
Operating Segments | Offshore pipeline transportation
Segment Reporting Information [Line Items]
Total consolidated assets	2,626,821	2,580,032
Operating Segments | Soda and sulfur services
Segment Reporting Information [Line Items]
Total consolidated assets	2,637,632	2,705,350
Operating Segments | Marine transportation
Segment Reporting Information [Line Items]
Total consolidated assets	640,032	645,020
Operating Segments | Onshore facilities and transportation
Segment Reporting Information [Line Items]
Total consolidated assets	963,604	1,019,113
Other assets
Segment Reporting Information [Line Items]
Total consolidated assets	$ 77,169	$ 69,263