Segment Information (Schedule Of Net Revenue By Geographic Areas) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Segment Reporting Information [Line Items]
Total net revenues	$ 355,483	$ 338,458	$ 1,009,863	$ 960,369
United States [Member]
Segment Reporting Information [Line Items]
Total net revenues	235,584	217,631	663,096	610,505
Americas Excluding United States [Member]
Segment Reporting Information [Line Items]
Total net revenues	8,804	7,604	19,870	19,488
EMEA [Member]
Segment Reporting Information [Line Items]
Total net revenues	62,161	60,034	175,810	176,192
APAC [Member]
Segment Reporting Information [Line Items]
Total net revenues	$ 48,934	$ 53,189	$ 151,087	$ 154,184