Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		$ 184,531	$ 195,636	$ 365,361	$ 440,165
Throughput and storage
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	[1]	22,375	21,684	44,892	42,542
Sulfur services
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		3,477	3,357	6,954	6,715
Terminalling and storage segment
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		22,375	21,684	44,892	42,542
Terminalling and storage segment | Throughput and storage
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		22,375	21,684	44,892	42,542
Transportation segment
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		57,676	54,750	115,983	110,473
Transportation segment | Land transportation
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		42,860	40,869	85,603	83,099
Transportation segment | Inland marine transportation
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		12,977	12,357	27,300	24,435
Transportation segment | Offshore marine transportation
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		1,839	1,524	3,080	2,939
Sulfur services segment
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		37,192	40,330	70,873	76,009
Sulfur services segment | Sulfur product sales
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		7,521	7,462	13,204	13,738
Sulfur services segment | Fertilizer product sales
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		26,194	29,511	50,715	55,556
Sulfur services segment | Sulfur services
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		3,477	3,357	6,954	6,715
Specialty products segment
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		67,288	78,872	133,613	211,141
Specialty products segment | Natural gas liquids product sales
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		35,435	45,678	73,566	143,900
Specialty products segment | Lubricant product sales
Disaggregation of Revenue
Revenue from Contract with Customer, Excluding Assessed Tax		$ 31,853	$ 33,194	$ 60,047	$ 67,241

[1] Related Party Transactions Included Above Three Months EndedSix Months EndedJune 30,June 30,2024202320242023Revenues:*    Terminalling and storage$18,078 $18,077 $36,627 $35,579 Transportation8,318 7,277 16,919 12,788 Product Sales123 7,497 252 8,422 Costs and expenses:* Cost of products sold: (excluding depreciation and amortization) Specialty products8,368 7,918 14,941 17,428 Sulfur services2,919 2,644 5,912 5,352 Terminalling and storage24 25 42 31 Expenses:Operating expenses26,501 25,058 52,924 48,885 Selling, general and administrative8,638 6,556 15,501 15,072