Business Segment Information (Schedule of Total Assets by Reportable Segment) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Total consolidated assets	$ 5,971,460	$ 5,905,801
Operating Segments | Offshore pipeline transportation
Segment Reporting Information [Line Items]
Total consolidated assets	2,142,264	2,103,140
Operating Segments | Sodium Minerals and Sulfur Services [Member]
Segment Reporting Information [Line Items]
Total consolidated assets	2,195,737	2,132,588
Operating Segments | Onshore Facilities and Transportation [Member]
Segment Reporting Information [Line Items]
Total consolidated assets	868,779	923,064
Operating Segments | Marine transportation
Segment Reporting Information [Line Items]
Total consolidated assets	705,265	703,030
Other assets
Segment Reporting Information [Line Items]
Total consolidated assets	$ 59,415	$ 43,979