Stockholders' Equity (Schedule of Reclassifications Out Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from accumulated other comprehensive income (loss)	$ (4,956)	$ 533	$ 453
Derivatives Designated As Hedging Instruments [Member] | Foreign Currency Forward Contracts [Member]
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Gain or (Loss) Reclassified from OCI into Income-Effective Portion	(7,624)	820	453
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	2,668	(287)	0	[1]
Amounts reclassified from accumulated other comprehensive income (loss)	(4,956)	533	453
Derivatives Designated As Hedging Instruments [Member] | Foreign Currency Forward Contracts [Member] | Net Revenue [Member]
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Gain or (Loss) Reclassified from OCI into Income-Effective Portion	(8,693)	1,100	462
Derivatives Designated As Hedging Instruments [Member] | Foreign Currency Forward Contracts [Member] | Cost Of Revenue [Member]
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Gain or (Loss) Reclassified from OCI into Income-Effective Portion	18	(6)	6
Derivatives Designated As Hedging Instruments [Member] | Foreign Currency Forward Contracts [Member] | Operating Expenses [Member]
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Gain or (Loss) Reclassified from OCI into Income-Effective Portion	$ 1,051	$ (274)	$ (15)

[1] Under the Company's 2015 tax structure, all hedging gains and losses from derivative contracts were ultimately borne by a legal entity in a jurisdiction with no income tax.