DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES: (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 28, 2014
Derivative contracts
Assets	$ 86	$ 23	$ 726
Liabilities	(3,602)	(2,699)	(495)
Derivatives designated as hedging instruments:
Derivative contracts
Assets	86	23	726
Liabilities	(3,602)	(2,699)	(495)
Derivatives designated as hedging instruments: | Foreign currency forward contracts
Derivative contracts
Notional Amounts	19,283	27,603	38,978
Assets			534
Liabilities	(2,494)	(1,939)	(453)
Derivatives designated as hedging instruments: | Commodity futures contracts
Derivative contracts
Notional Amounts	12,799	5,422	5,563
Assets	86	23	192
Liabilities	$ (1,108)	$ (760)	$ (42)