Summary Of Significant Accounting Policies (Narrative) (Details) number in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Amortization	$ 58,149	$ 61,041	$ 60,700
Provisions for doubtful accounts	1,304	2,104	1,465
Net foreign exchange gains (losses)	486	(1,649)	$ (1,115)
Reclassification of certain deferred taxes to long-term deferred tax assets	32,896	28,240
Reclassification of certain deferred taxes to long-term deferred tax liabilities	$ 2,091	$ 16,190
Minimum [Member]
Frequency period of major product upgrades (months)	12 months
Semiconductor product licenses, term	24 months
Property and equipment, estimated useful lives (years)	1 year
Maximum [Member]
Frequency period of major product upgrades (months)	18 months
Semiconductor product licenses, term	36 months
Property and equipment, estimated useful lives (years)	40 years
Customer Concentration Risk [Member]
Number of customers with more than five percent of revenue	0	0	0
Adjustments for New Accounting Pronouncement [Member]
Reclassification of certain deferred taxes to long-term deferred tax assets		$ 7,000
Reclassification of certain deferred taxes to long-term deferred tax liabilities		$ 21,200