INVENTORIES (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
INVENTORIES [Abstract]
Inventory classified as long-term assets (other noncurrent assets)	$ 15,285	$ 14,995
Inventories valued under the LIFO method	239,187	242,147
Decrease in cost of revenues due to the effect of the LIFO liquidation	3,956	3,284	$ 2,686
Increase in net earnings due to the effect of the LIFO liquidation	2,419	2,010	1,650
Excess of estimated current cost over LIFO cost	155,576	169,257
Approximate effect on net earnings due to the adoption of the LIFO method	$ (8,338)	$ (7,614)	$ 19,108