Accumulated Other Comprehensive (Loss) Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2013	Jun. 29, 2012	Jun. 28, 2013	Jun. 29, 2012
Accumulated unrealized gain (loss) on available-for-sale securities, net of tax
December 31, 2012			$ 5,592
Other Comprehensive (Loss) Income	(9,068)	2,796	(9,118)	3,080
June 28, 2013	(3,526)		(3,526)
Accumulated other comprehensive (loss) income
December 31, 2012			5,592
Other Comprehensive (Loss) Income	(9,068)	2,817	(9,118)	3,065
June 28, 2013	$ (3,526)		$ (3,526)