Marketable Securities (Details) (Marketable debt securities [Member], USD $) In Thousands, unless otherwise specified	Sep. 28, 2014	Dec. 29, 2013
Investment [Line Items]
Short-term marketable securities	$ 371,925	$ 364,880
Long-term marketable securities	179,137	176,155
U.S. Treasury securities [Member]
Investment [Line Items]
Short-term marketable securities	66,985	143,510
Corporate debt securities [Member]
Investment [Line Items]
Short-term marketable securities	172,318	78,991
Long-term marketable securities	88,169	98,979
U.S. agency securities [Member]
Investment [Line Items]
Short-term marketable securities	45,021	31,518
Long-term marketable securities	87,590	73,697
Municipal securities [Member]
Investment [Line Items]
Short-term marketable securities	24,839	48,035
Long-term marketable securities	3,378	3,479
Certificates of deposit [Member]
Investment [Line Items]
Short-term marketable securities	57,763	31,949
Commercial paper [Member]
Investment [Line Items]
Short-term marketable securities	$ 4,999	$ 30,877