Derivative Financial Instruments (Schedule Of Company's Derivative Instruments On Other Comprehensive Income And The Consolidated Statement Of Operations) (Details) - Derivatives Designated As Hedging Instruments [Member] - Foreign Currency Forward Contracts [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (Loss) Recognized in OCI-Effective Portion	$ (3,538)	$ (417)	$ (10,590)	$ (1,116)
Derivative Instruments, Gain (Loss) Reclassified from AOCI into Income, Effective Portion	(3,560)	(657)	(2,912)	(1,320)
Amount of Gain or (Loss) Recognized in Income and Excluded from Effectiveness Testing	528	116	1,196	169
Net Revenue [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from AOCI into Income, Effective Portion	(4,401)	(824)	(3,374)	(1,543)
Cost Of Revenue [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from AOCI into Income, Effective Portion	19	4	5	4
Operating Expenses [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from AOCI into Income, Effective Portion	822	163	457	219
Other Income (expense), Net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income and Excluded from Effectiveness Testing	$ 528	$ 116	$ 1,196	$ 169