Revenue Recognition (Disaggregated Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenues	$ 539,923	$ 620,009
Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	181,765	172,979
Product Sales
Disaggregation of Revenue [Line Items]
Total revenues	330,134	429,387
Refinery Services
Disaggregation of Revenue [Line Items]
Total revenues	28,024	17,643
Offshore Pipeline Transportation
Disaggregation of Revenue [Line Items]
Total revenues	78,429	78,317
Offshore Pipeline Transportation | Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	78,429	78,317
Offshore Pipeline Transportation | Product Sales
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Offshore Pipeline Transportation | Refinery Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Sodium Minerals & Sulfur Services
Disaggregation of Revenue [Line Items]
Total revenues	243,390	275,486
Sodium Minerals & Sulfur Services | Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Sodium Minerals & Sulfur Services | Product Sales
Disaggregation of Revenue [Line Items]
Total revenues	215,366	257,843
Sodium Minerals & Sulfur Services | Refinery Services
Disaggregation of Revenue [Line Items]
Total revenues	28,024	17,643
Marine Transportation
Disaggregation of Revenue [Line Items]
Total revenues	62,346	56,650
Marine Transportation | Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	62,346	56,650
Marine Transportation | Product Sales
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Marine Transportation | Refinery Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Onshore Facilities & Transportation
Disaggregation of Revenue [Line Items]
Total revenues	155,758	209,556
Onshore Facilities & Transportation | Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	40,990	38,012
Onshore Facilities & Transportation | Product Sales
Disaggregation of Revenue [Line Items]
Total revenues	114,768	171,544
Onshore Facilities & Transportation | Refinery Services
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ 0