DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES: (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 29, 2014
Derivative contracts
Assets	$ 31	$ 23	$ 388
Liabilities	(5,068)	(2,699)	(1,613)
Derivatives designated as hedging instruments:
Derivative contracts
Assets	31	23	382
Liabilities	(5,068)	(2,699)	(1,613)
Derivatives designated as hedging instruments: | Foreign currency forward contracts
Derivative contracts
Notional Amounts	23,443	27,603	44,665
Liabilities	(3,328)	(1,939)	(1,613)
Derivatives designated as hedging instruments: | Commodity futures contracts
Derivative contracts
Notional Amounts	15,966	5,422	5,154
Assets	31	23	382
Liabilities	(1,740)	(760)
Derivatives not designated as hedging instruments:
Derivative contracts
Assets			6
Derivatives not designated as hedging instruments: | Commodity futures contracts
Derivative contracts
Notional Amounts			195
Assets			$ 6