Revenue Recognition (Disaggregated Revenue) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Disaggregation of Revenue [Line Items]
Total revenues	$ 446,555,000	$ 398,311,000
Other Assets, net of amortization	5,822,000		$ 7,469,000
Accrued Liabilities	29,614,000		26,982,000
Other Long-Term Liabilities	76,945,000		78,946,000
Contract with Customer, Asset, Allowance for Credit Loss, Current	1,692,000		$ 32,000
Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	242,845,000	203,036,000
Product sales
Disaggregation of Revenue [Line Items]
Total revenues	188,612,000	174,263,000
Sulfur services
Disaggregation of Revenue [Line Items]
Total revenues	15,098,000	21,012,000
Offshore pipeline transportation
Disaggregation of Revenue [Line Items]
Total revenues	147,281,000	108,887,000
Offshore pipeline transportation | Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	147,281,000	108,887,000
Offshore pipeline transportation | Product sales
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Offshore pipeline transportation | Sulfur services
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Marine transportation
Disaggregation of Revenue [Line Items]
Total revenues	80,045,000	80,644,000
Marine transportation | Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	80,045,000	80,644,000
Marine transportation | Product sales
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Marine transportation | Sulfur services
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Onshore transportation and services
Disaggregation of Revenue [Line Items]
Total revenues	219,229,000	208,780,000
Onshore transportation and services | Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	15,519,000	13,505,000
Onshore transportation and services | Product sales
Disaggregation of Revenue [Line Items]
Total revenues	188,612,000	174,263,000
Onshore transportation and services | Sulfur services
Disaggregation of Revenue [Line Items]
Total revenues	$ 15,098,000	$ 21,012,000