Revenue Recognition (Disaggregated Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenues	$ 503,855	$ 388,467	$ 1,025,074	$ 928,390
Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	139,023	143,529	268,132	325,294
Product Sales
Disaggregation of Revenue [Line Items]
Total revenues	340,179	224,724	709,780	554,858
Refinery Services
Disaggregation of Revenue [Line Items]
Total revenues	24,653	20,214	47,162	48,238
Offshore Pipeline Transportation
Disaggregation of Revenue [Line Items]
Total revenues	73,221	64,964	137,605	143,393
Offshore Pipeline Transportation | Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	73,221	64,964	137,605	143,393
Offshore Pipeline Transportation | Product Sales
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Offshore Pipeline Transportation | Refinery Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Sodium Minerals & Sulfur Services
Disaggregation of Revenue [Line Items]
Total revenues	237,087	192,624	464,374	436,014
Sodium Minerals & Sulfur Services | Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Sodium Minerals & Sulfur Services | Product Sales
Disaggregation of Revenue [Line Items]
Total revenues	212,434	172,410	417,212	387,776
Sodium Minerals & Sulfur Services | Refinery Services
Disaggregation of Revenue [Line Items]
Total revenues	24,653	20,214	47,162	48,238
Marine Transportation
Disaggregation of Revenue [Line Items]
Total revenues	47,626	56,720	87,957	119,066
Marine Transportation | Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	47,626	56,720	87,957	119,066
Marine Transportation | Product Sales
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Marine Transportation | Refinery Services
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Onshore Facilities and Transportation
Disaggregation of Revenue [Line Items]
Total revenues	145,921	74,159	335,138	229,917
Onshore Facilities and Transportation | Fee-based revenues
Disaggregation of Revenue [Line Items]
Total revenues	18,176	21,845	42,570	62,835
Onshore Facilities and Transportation | Product Sales
Disaggregation of Revenue [Line Items]
Total revenues	127,745	52,314	292,568	167,082
Onshore Facilities and Transportation | Refinery Services
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ 0	$ 0	$ 0