Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Revenues		$ 198,883	$ 240,033
Lubricant product sales
Disaggregation of Revenue [Line Items]
Revenues		28,934	31,067
Throughput and storage
Disaggregation of Revenue [Line Items]
Revenues	[1]	20,474	23,104
Natural gas liquids product sales
Disaggregation of Revenue [Line Items]
Revenues		82,211	116,474
Sulfur services
Disaggregation of Revenue [Line Items]
Revenues		2,915	2,859
Terminalling and storage segment
Disaggregation of Revenue [Line Items]
Revenues		49,408	54,171
Terminalling and storage segment | Lubricant product sales
Disaggregation of Revenue [Line Items]
Revenues		28,934	31,067
Terminalling and storage segment | Throughput and storage
Disaggregation of Revenue [Line Items]
Revenues		20,474	23,104
Natural gas liquids segment
Disaggregation of Revenue [Line Items]
Revenues		82,211	116,474
Natural gas liquids segment | Natural gas liquids product sales
Disaggregation of Revenue [Line Items]
Revenues		82,211	116,474
Sulfur services segment
Disaggregation of Revenue [Line Items]
Revenues		28,323	31,593
Sulfur services segment | Sulfur product sales
Disaggregation of Revenue [Line Items]
Revenues		6,481	9,952
Sulfur services segment | Fertilizer product sales
Disaggregation of Revenue [Line Items]
Revenues		18,927	18,782
Sulfur services segment | Sulfur services
Disaggregation of Revenue [Line Items]
Revenues		2,915	2,859
Transportation segment
Disaggregation of Revenue [Line Items]
Revenues		38,941	37,795
Transportation segment | Land transportation
Disaggregation of Revenue [Line Items]
Revenues		24,234	24,119
Transportation segment | Inland transportation
Disaggregation of Revenue [Line Items]
Revenues		13,706	12,477
Transportation segment | Offshore transportation
Disaggregation of Revenue [Line Items]
Revenues		$ 1,001	$ 1,199

[1] Related Party Transactions Included Above   Three Months Ended   March 31,   2020   2019 Revenues:*       Terminalling and storage $ 15,874
  $ 18,972
Transportation 5,894
  5,643
Product Sales 92
  421
Costs and expenses:*       Cost of products sold: (excluding depreciation and amortization)       Sulfur services 2,767
  2,574
Terminalling and storage 5,777
  5,909
Expenses:       Operating expenses 21,771
  22,536
Selling, general and administrative 8,312
  8,535