Marketable Securities (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Sep. 24, 2011 day Y	Dec. 25, 2010
Marketable securities
Amortized Cost	$ 18,160	$ 21,808
Gross Unrealized Losses	(902)	(597)
Fair Value	17,258	21,211
Maturities of debt securities, Amortized Cost
Due less than one year, Amortized Cost	6,188	9,834
Due after ten years, Amortized Cost	11,972	11,974
Amortized Cost	18,160	21,808
Maturities of debt securities, Fair Value
Due less than one year, Fair Value	6,188	9,834
Due after ten years, Fair Value	11,070	11,377
Fair Value	17,258	21,211
Time deposits
Marketable securities
Amortized Cost	6,188	9,834
Fair Value	6,188	9,834
Maturities of debt securities, Fair Value
Fair Value	6,188	9,834
Auction rate securities
Marketable securities
Amortized Cost	11,972	11,974
Gross Unrealized Losses	(902)	(597)
Fair Value	11,070	11,377
Variable rate debt instruments	11,070
Interest rate reset period for variable rate demand notes (in days)	35
Contractual maturity minimum (in years)	10
Maturities of debt securities, Fair Value
Fair Value	$ 11,070	$ 11,377

Represents the minimum number of years that a debt security categorized as neither trading nor held-to-maturity is scheduled to be repaid.

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Represents the number of days, after which the interest rate for a debt security categorized as neither trading nor held-to-maturity, is reset.

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Represents the cost of variable rate debt securities, which are categorized neither as held-to-maturity nor trading.

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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This item represents debt securities, at cost, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments, as defined), and fair value hedge accounting adjustments, if any, which are expected to mature after ten years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.

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This item represents the fair value of debt securities which are expected to mature after ten years from the balance sheet date which are categorized neither as held-to-maturity nor trading securities.

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This item represents the total of all debt securities grouped by maturity dates, at cost, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments, as defined), and fair value hedge accounting adjustments, if any, which are classified neither as held-to-maturity nor trading securities.

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This item represents debt securities, at cost, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments, as defined), and fair value hedge accounting adjustments, if any, which are expected to mature within one year of the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.

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This item represents the fair value of debt securities which are expected to mature within one year of the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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This item represents the gross unrealized losses for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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