Marketable Securities (Details) (USD $) In Thousands, unless otherwise specified	Jul. 01, 2012	Apr. 01, 2012
Schedule of Available-For-Sale Securities
Available-for-sale securities, Amortized Cost	$ 377,825	$ 372,136
Available-for-sale securities, Gross Unrealized Gains	1,702	1,622
Available-for-sale securities, Gross Unrealized Losses	(237)	(319)
Available-for-sale securities, Estimated Fair Value	379,290	373,439
U.S. Government and agency securities [Member]
Schedule of Available-For-Sale Securities
Available-for-sale securities, Amortized Cost	130,273	141,680
Available-for-sale securities, Gross Unrealized Gains	286	257
Available-for-sale securities, Gross Unrealized Losses	(28)	(78)
Available-for-sale securities, Estimated Fair Value	130,531	141,859
Corporate debt obligations [Member]
Schedule of Available-For-Sale Securities
Available-for-sale securities, Amortized Cost	170,682	166,763
Available-for-sale securities, Gross Unrealized Gains	1,014	1,071
Available-for-sale securities, Gross Unrealized Losses	(116)	(166)
Available-for-sale securities, Estimated Fair Value	171,580	167,668
Asset and mortgage-backed securities [Member]
Schedule of Available-For-Sale Securities
Available-for-sale securities, Amortized Cost	48,817	46,395
Available-for-sale securities, Gross Unrealized Gains	352	272
Available-for-sale securities, Gross Unrealized Losses	(72)	(73)
Available-for-sale securities, Estimated Fair Value	49,097	46,594
Municipal bonds [Member]
Schedule of Available-For-Sale Securities
Available-for-sale securities, Amortized Cost	28,053	16,548
Available-for-sale securities, Gross Unrealized Gains	50	22
Available-for-sale securities, Gross Unrealized Losses	(21)	(2)
Available-for-sale securities, Estimated Fair Value	28,082	16,568
Other debt securities [Member]
Schedule of Available-For-Sale Securities
Available-for-sale securities, Amortized Cost		750
Available-for-sale securities, Estimated Fair Value		$ 750

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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- Definition

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

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