Business Segment Information (Schedule of Total Assets by Reportable Segment) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Total assets	$ 6,669,459	$ 6,365,992
Operating Segments | Offshore pipeline transportation
Segment Reporting Information [Line Items]
Total assets	2,370,338	2,290,488
Operating Segments | Sodium Minerals and Sulfur Services [Member]
Segment Reporting Information [Line Items]
Total assets	2,560,004	2,358,086
Operating Segments | Onshore Facilities and Transportation [Member]
Segment Reporting Information [Line Items]
Total assets	1,021,965	981,354
Operating Segments | Marine transportation
Segment Reporting Information [Line Items]
Total assets	650,443	681,231
Other assets
Segment Reporting Information [Line Items]
Total assets	$ 66,709	$ 54,833