Segment Data (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) Segment	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment			2
Revenues [Abstract]
Revenues	$ 598,920,000	$ 496,567,000	$ 1,655,394,000	$ 1,681,652,000
Segment profit (loss)	(325,594,000)	19,274,000	(313,760,000)	(476,664,000)
Total assets	5,389,882,000		5,389,882,000		$ 5,924,174,000
Other segment disclosures [Abstract]
(Gain) loss on disposition of assets	830,000	(316,000)	5,082,000	13,000
Interest expense	(10,500,000)	(11,809,000)	(32,172,000)	(37,316,000)
Earnings (loss) before taxes on income	(325,594,000)	19,274,000	(313,760,000)	(476,664,000)
Marine Transportation [Member]
Revenues [Abstract]
Revenues	338,514,000	320,602,000	972,352,000	1,104,846,000
Distribution and Services [Member]
Revenues [Abstract]
Revenues	260,406,000	175,965,000	683,042,000	576,806,000
Other [Member]
Revenues [Abstract]
Segment profit (loss)	(353,548,000)	(14,221,000)	(371,199,000)	(601,821,000)
Total assets	212,298,000		212,298,000		357,894,000
Other segment disclosures [Abstract]
General corporate expenses	(4,997,000)	(3,268,000)	(11,542,000)	(9,403,000)
(Gain) loss on disposition of assets	830,000	(316,000)	5,082,000	(13,000)
Impairments and other charges	(340,713,000)	0	(340,713,000)	(561,274,000)
Interest expense	(10,500,000)	(11,809,000)	(32,172,000)	(37,316,000)
Other income	1,832,000	1,172,000	8,146,000	6,185,000
Earnings (loss) before taxes on income	(353,548,000)	(14,221,000)	(371,199,000)	(601,821,000)
Details of Other total assets [Abstract]
General corporate assets	210,311,000		210,311,000		355,205,000
Investment in affiliates	1,987,000		1,987,000		2,689,000
Total other assets	212,298,000		212,298,000		357,894,000
Reporting Segments [Member] | Marine Transportation [Member]
Revenues [Abstract]
Revenues	338,514,000	320,602,000	972,352,000	1,104,846,000
Segment profit (loss)	16,915,000	32,391,000	37,333,000	134,482,000
Total assets	4,320,452,000		4,320,452,000		4,760,449,000
Other segment disclosures [Abstract]
Earnings (loss) before taxes on income	16,915,000	32,391,000	37,333,000	134,482,000
Reporting Segments [Member] | Distribution and Services [Member]
Revenues [Abstract]
Revenues	260,406,000	175,965,000	683,042,000	576,806,000
Segment profit (loss)	11,039,000	1,104,000	20,106,000	(9,325,000)
Total assets	857,132,000		857,132,000		$ 805,831,000
Other segment disclosures [Abstract]
Earnings (loss) before taxes on income	11,039,000	1,104,000	20,106,000	(9,325,000)
Intersegment Eliminations [Member]
Revenues [Abstract]
Revenues	5,436,000	6,768,000	17,593,000	23,115,000
Segment profit (loss)	543,000	676,000	1,759,000	2,311,000
Other segment disclosures [Abstract]
Earnings (loss) before taxes on income	$ 543,000	$ 676,000	$ 1,759,000	$ 2,311,000