Business Segment Information (Schedule of Total Assets by Reportable Segment) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
TOTAL ASSETS	$ 5,905,801	$ 5,933,619	$ 6,597,641
Operating Segments | Offshore pipeline transportation
Segment Reporting Information [Line Items]
TOTAL ASSETS	2,103,140	2,187,083	2,306,946
Operating Segments | Sodium minerals and sulfur services
Segment Reporting Information [Line Items]
TOTAL ASSETS	2,132,588	1,962,146	2,019,905
Operating Segments | Onshore facilities and transportation
Segment Reporting Information [Line Items]
TOTAL ASSETS	923,064	1,035,662	1,457,190
Operating Segments | Marine transportation
Segment Reporting Information [Line Items]
TOTAL ASSETS	703,030	711,058	772,383
Other assets
Segment Reporting Information [Line Items]
TOTAL ASSETS	$ 43,979	$ 37,670	$ 41,217