SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue recognition:
Shipping and handling costs	$ 40,629	$ 42,619	$ 46,525
Cash and cash equivalents:
Maximum original maturity period of temporary cash investments classified as cash equivalents	3 months
Investments:
Marketable securities, maximum maturity period	3 years
Inventories:
Inventories at cost, last-in, first-out (LIFO) method	$ 53,278	58,413
Excess of current cost over LIFO cost of inventories	17,574	16,864
Foreign inventories at cost, first-in, first-out (FIFO) method	$ 4,253	$ 3,850