Marketable Securities Composition (Details) (USD $) In Thousands, unless otherwise specified	Dec. 29, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Maturities of less than five years	$ 64,865	$ 68,711
Maturities of more than ten years	4,717	6,946
Available-for-sale Securities	69,582	75,657
Short-term marketable securities \| Corporate and government bonds and notes and commercial paper
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	64,865	68,711
Long-term marketable securities \| Federally-insured or FFELP guaranteed student loan auction rate securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	$ 4,717	$ 6,946

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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+ Details