Segment Data (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) Segment	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	2
Revenues [Abstract]
Revenues	$ 750,444	$ 610,782
Segment profit	54,672	23,799
Total assets	5,574,748		$ 5,554,924
Other segment disclosures [Abstract]
Gain on disposition of assets	2,230	4,849
Interest expense	(13,221)	(10,203)
Earnings before taxes on income	54,672	23,799
Marine Transportation (KMT) [Member]
Revenues [Abstract]
Revenues	412,495	355,536
Distribution and Services [Member]
Revenues [Abstract]
Revenues	337,949	255,246
Other [Member]
Revenues [Abstract]
Segment profit	(11,156)	(4,107)
Total assets	180,974		227,436
Other segment disclosures [Abstract]
General corporate expenses	(6,608)	(3,061)
Gain on disposition of assets	2,230	4,849
Interest expense	(13,221)	(10,203)
Other income	6,443	4,308
Earnings before taxes on income	(11,156)	(4,107)
Details of "Other" total assets [Abstract]
General corporate assets	178,619		225,265
Investment in affiliates	2,355		2,171
Total other assets	180,974		227,436
Reporting Segments [Member] | Marine Transportation (KMT) [Member]
Revenues [Abstract]
Revenues	412,495	355,536
Segment profit	43,036	16,935
Total assets	4,285,085		4,285,647
Other segment disclosures [Abstract]
Earnings before taxes on income	43,036	16,935
Reporting Segments [Member] | Distribution and Services [Member]
Revenues [Abstract]
Revenues	337,949	255,246
Segment profit	22,792	10,971
Total assets	1,108,689		$ 1,041,841
Other segment disclosures [Abstract]
Earnings before taxes on income	22,792	10,971
Intersegment Eliminations [Member]
Revenues [Abstract]
Revenues	9,400	7,600
Segment profit	900	800
Other segment disclosures [Abstract]
Earnings before taxes on income	$ 900	$ 800