Segment Data (Details)	3 Months Ended
	Mar. 31, 2022 USD ($) Segment	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	2
Revenues [Abstract]
Total revenues	$ 610,782,000	$ 496,850,000
Segment profit (loss)	23,799,000	(4,011,000)
Total assets	5,382,792,000		$ 5,399,063,000
Other segment disclosures [Abstract]
(Gain) loss on disposition of assets	4,849,000	2,133,000
Interest expense	(10,203,000)	(10,966,000)
Earnings (loss) before taxes on income	23,799,000	(4,011,000)
Marine Transportation [Member]
Revenues [Abstract]
Total revenues	355,536,000	300,951,000
Distribution and Services [Member]
Revenues [Abstract]
Total revenues	255,246,000	195,899,000
Other [Member]
Revenues [Abstract]
Segment profit (loss)	(4,107,000)	(8,862,000)
Total assets	179,752,000		187,380,000
Other segment disclosures [Abstract]
General corporate expenses	3,061,000	3,820,000
(Gain) loss on disposition of assets	4,849,000	2,133,000
Interest expense	10,203,000	10,966,000
Other income	4,308,000	3,791,000
Earnings (loss) before taxes on income	(4,107,000)	(8,862,000)
Details of Other total assets [Abstract]
General corporate assets	178,199,000		185,246,000
Investment in affiliates	1,553,000		2,134,000
Total other assets	179,752,000		187,380,000
Reporting Segments [Member]
Revenues [Abstract]
Segment profit (loss)		1,940,000
Other segment disclosures [Abstract]
Earnings (loss) before taxes on income		1,940,000
Reporting Segments [Member] | Marine Transportation [Member]
Revenues [Abstract]
Total revenues	355,536,000	300,951,000
Segment profit (loss)	16,935,000
Total assets	4,280,135,000		4,319,080,000
Other segment disclosures [Abstract]
Earnings (loss) before taxes on income	16,935,000
Reporting Segments [Member] | Distribution and Services [Member]
Revenues [Abstract]
Total revenues	255,246,000	195,899,000
Segment profit (loss)	10,971,000	2,911,000
Total assets	922,905,000		$ 892,603,000
Other segment disclosures [Abstract]
Earnings (loss) before taxes on income	10,971,000	2,911,000
Intersegment Eliminations [Member]
Revenues [Abstract]
Total revenues	7,600	4,900
Segment profit (loss)	800,000	500
Other segment disclosures [Abstract]
Earnings (loss) before taxes on income	$ 800,000	$ 500