Schedule Of Net Revenue By Geography Periods (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 27, 2015	Jun. 28, 2015	Mar. 29, 2015	Dec. 31, 2014	Sep. 28, 2014	Jun. 29, 2014	Mar. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Total net revenues	$ 360,863	$ 341,893	$ 288,782	$ 309,157	$ 353,182	$ 353,338	$ 337,604	$ 349,391	$ 1,300,695	$ 1,393,515	$ 1,369,633
United States [Member]
Segment Reporting Information [Line Items]
Total net revenues									779,361	750,933	769,357
Americas Excluding United States [Member]
Segment Reporting Information [Line Items]
Total net revenues									18,385	19,957	19,961
United Kingdom [Member]
Segment Reporting Information [Line Items]
Total net revenues									103,649	154,503	142,729
EMEA Excluding United Kingdom [Member]
Segment Reporting Information [Line Items]
Total net revenues									218,065	267,384	269,959
APAC [Member]
Segment Reporting Information [Line Items]
Total net revenues									$ 181,235	$ 200,738	$ 167,627