SEGMENT DATA (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) Segment	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
SEGMENT DATA [Abstract]
Number of reportable segments | Segment	2
Revenues [Abstract]
Revenues	$ 744,621	$ 741,688
Segment profit (loss)	58,337	42,531
Total assets	6,300,692		$ 5,871,594
Other segment disclosures [Abstract]
Gain on disposition of assets	2,157	1,898
Interest expense	(13,201)	(9,780)
Other income (expense)	(568)	1,591
Earnings before taxes on income	58,337	42,531
Marine Transportation [Member]
Revenues [Abstract]
Revenues	368,121	340,403
Distribution and Services [Member]
Revenues [Abstract]
Revenues	376,500	401,285
Other [Member]
Revenues [Abstract]
Segment profit (loss)	(14,696)	(10,614)
Total assets	94,524		72,664
Other segment disclosures [Abstract]
General corporate expenses	(3,084)	(4,323)
Gain on disposition of assets	2,157	1,898
Interest expense	(13,201)	(9,780)
Other income (expense)	(568)	1,591
Earnings before taxes on income	(14,696)	(10,614)
Details of "Other" total assets [Abstract]
General corporate assets	92,805		70,169
Investment in affiliates	1,719		2,495
Total other assets	94,524		72,664
Reporting Segments [Member] | Marine Transportation [Member]
Revenues [Abstract]
Revenues	368,121	340,403
Segment profit (loss)	35,424	16,180
Total assets	4,510,945		4,145,294
Other segment disclosures [Abstract]
Earnings before taxes on income	35,424	16,180
Reporting Segments [Member] | Distribution and Services [Member]
Revenues [Abstract]
Revenues	376,500	401,285
Segment profit (loss)	37,609	36,965
Total assets	1,695,223		$ 1,653,636
Other segment disclosures [Abstract]
Earnings before taxes on income	37,609	36,965
Intersegment Eliminations [Member]
Revenues [Abstract]
Revenues	7,535	8,150
Segment profit (loss)	754	815
Other segment disclosures [Abstract]
Earnings before taxes on income	$ 754	$ 815