DERIVATIVES AND HEDGING ACTIVITIES: (Details)			3 Months Ended			3 Months Ended
	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Mar. 31, 2015 Foreign currency forward contract USD ($)	Mar. 31, 2015 Foreign currency forward contract ILS	Dec. 31, 2014 Foreign currency forward contract USD ($)	Mar. 31, 2015 Foreign currency forward contract Amount Reclassified from Other Comprehensive Income / Loss Gains / Losses on Derivatives USD ($)	Mar. 31, 2014 Foreign currency forward contract Amount Reclassified from Other Comprehensive Income / Loss Gains / Losses on Derivatives USD ($)
Derivatives and Hedging Activities
Future operating expenses hedged			$ 87,300,000	347,300,000
Period over which operating expenses hedged will be expensed			12 months
Derivative Liabilities Reported in Other Current Liabilities
Foreign exchange contracts designated as cash flow hedges			3,272,000		3,562,000
Total derivatives designated as hedging instruments	3,272,000	3,562,000
Balance of designated derivative contracts as cash flow hedges and their impact on OCI
Balance at the beginning of the period			(3,646,000)
Amount of loss recognized in OCI (effective portion)			(1,899,000)
Amount of loss reclassified from OCI to income (effective portion)			2,273,000
Balance at the end of the period			(3,272,000)
Expected time to realize the accumulated OCI balance related to foreign exchange contracts			12 months
Gain on foreign exchange contracts designated as cash flow hedges						$ (2,273,000)	$ 700,000