Business Segment Information (Schedule of Segment Information) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Total Segment Margin	$ 168,313	$ 214,618	$ 349,411	$ 409,747
Revenues	756,261	804,662	1,526,366	1,595,274
Offshore pipeline transportation
Segment Reporting Information [Line Items]
Revenues	99,024	91,459	201,014	182,854
Soda and sulfur services
Segment Reporting Information [Line Items]
Revenues	389,994	462,855	790,942	907,503
Onshore facilities and transportation
Segment Reporting Information [Line Items]
Revenues	185,372	173,005	368,965	344,348
Marine transportation
Segment Reporting Information [Line Items]
Revenues	81,871	77,343	165,445	160,569
Operating Segments
Segment Reporting Information [Line Items]
Total Segment Margin	168,313	214,618	349,411	409,747
Capital expenditures	110,118	131,345	211,175	214,370
Revenues	756,261	804,662	1,526,366	1,595,274
Operating Segments | Offshore pipeline transportation
Segment Reporting Information [Line Items]
Total Segment Margin	86,131	93,300	183,937	191,238
Capital expenditures	55,788	91,645	119,414	143,698
Revenues	99,024	91,459	201,014	182,854
Operating Segments | Soda and sulfur services
Segment Reporting Information [Line Items]
Total Segment Margin	41,611	89,255	86,993	155,362
Capital expenditures	18,106	26,622	36,706	46,607
Revenues	392,226	465,077	795,179	911,983
Operating Segments | Onshore facilities and transportation
Segment Reporting Information [Line Items]
Total Segment Margin	9,028	6,305	15,575	11,695
Capital expenditures	6,692	2,088	13,213	4,018
Revenues	183,140	170,783	364,728	339,868
Operating Segments | Marine transportation
Segment Reporting Information [Line Items]
Total Segment Margin	31,543	25,758	62,906	51,452
Capital expenditures	29,532	10,990	41,842	20,047
Revenues	81,871	77,343	165,445	160,569
Intersegment
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Intersegment | Offshore pipeline transportation
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Intersegment | Soda and sulfur services
Segment Reporting Information [Line Items]
Revenues	(2,232)	(2,222)	(4,237)	(4,480)
Intersegment | Onshore facilities and transportation
Segment Reporting Information [Line Items]
Revenues	2,232	2,222	4,237	4,480
Intersegment | Marine transportation
Segment Reporting Information [Line Items]
Revenues	$ 0	$ 0	$ 0	$ 0