DERIVATIVES AND HEDGING ACTIVITIES: (Details)			12 Months Ended				12 Months Ended
	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2013 Foreign currency forward contract USD ($)	Dec. 31, 2013 Foreign currency forward contract ILS	Dec. 31, 2012 Foreign currency forward contract USD ($)	Dec. 31, 2012 Foreign currency forward contract ILS	Dec. 31, 2013 Foreign currency forward contract Amount Reclassified from Other Comprehensive Income / Loss Gains / Losses on Derivatives USD ($)	Dec. 31, 2012 Foreign currency forward contract Amount Reclassified from Other Comprehensive Income / Loss Gains / Losses on Derivatives USD ($)	Dec. 31, 2011 Foreign currency forward contract Amount Reclassified from Other Comprehensive Income / Loss Gains / Losses on Derivatives USD ($)
Derivatives and Hedging Activities
Future operating expenses hedged			$ 31,300,000	108,800,000	$ 58,900,000	219,900,000
Period over which operating expenses hedged will be expensed			12 months
Derivative Assets Reported in Other Current Assets
Foreign exchange contracts designated as cash flow hedges			1,396,000		2,942,000
Total derivatives designated as hedging instruments	1,396,000	2,942,000
Balance of designated derivative contracts as cash flow hedges and their impact on OCI
Balance at the beginning of the period			2,942,000
Amount of gain recognized in OCI (effective portion)			4,481,000
Amount of gain reclassified from OCI to income (effective portion)			(6,027,000)
Balance at the end of the period			1,396,000
Expected time to realize the accumulated OCI balance related to foreign exchange contracts			12 months
Gain (loss) on foreign exchange contracts designated as cash flow hedges							$ 6,027,000	$ (893,000)	$ 1,223,000