Financial Instruments Measured at Fair Value - AFS (Details) (USD $) In Thousands, unless otherwise specified	Mar. 30, 2013	Dec. 31, 2012
Marubun [Member]
Schedule of Available-for-sale Securities [Line Items]
Available For Sale Investment Ownership Percentage	8.40%
Cost basis	$ 10,016	$ 10,016
Unrealized holding gain	734	85
Total	10,750	10,101
WPG [Member]
Schedule of Available-for-sale Securities [Line Items]
Available For Sale Investment Ownership Percentage	1.90%
Cost basis	10,798	10,798
Unrealized holding gain	24,890	29,784
Total	35,688	40,582
Mutual Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost basis	15,312	15,271
Unrealized holding gain	2,975	1,949
Total	$ 18,287	$ 17,220

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 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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