INVENTORIES (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
INVENTORIES [Abstract]
Inventory classified as long-term assets (other noncurrent assets)	$ 14,995	$ 17,449
Inventories valued under the LIFO method	242,147	232,371
Decrease in cost of revenues due to the effect of the LIFO liquidation	3,284	2,686	$ 1,310
Increase in net earnings due to the effect of the LIFO liquidation	2,010	1,650	802
Excess of estimated current cost over LIFO cost	169,257	181,633
Approximate effect on net earnings due to the adoption of the LIFO method	$ (7,614)	$ 19,108	$ 20,812