Marketable Securities - Schedule of Available-for-Sale Securities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 29, 2013	Mar. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Amortized Cost	$ 353,087	$ 357,608
Available-for-sale securities, Gross Unrealized Gains	1,178	2,441
Available-for-sale securities, Gross Unrealized Losses	(832)	(75)
Available-for-sale securities, Estimated Fair Value	353,433	359,974
U.S. government and agency securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Amortized Cost	88,052	113,033
Available-for-sale securities, Gross Unrealized Gains	41	327
Available-for-sale securities, Gross Unrealized Losses	(176)	(1)
Available-for-sale securities, Estimated Fair Value	87,917	113,359
Corporate debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Amortized Cost	175,713	153,460
Available-for-sale securities, Gross Unrealized Gains	838	1,429
Available-for-sale securities, Gross Unrealized Losses	(207)	(30)
Available-for-sale securities, Estimated Fair Value	176,344	154,859
Mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Amortized Cost	48,507	50,852
Available-for-sale securities, Gross Unrealized Gains	214	473
Available-for-sale securities, Gross Unrealized Losses	(348)	(44)
Available-for-sale securities, Estimated Fair Value	48,373	51,281
Other debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Amortized Cost	3,558	602
Available-for-sale securities, Gross Unrealized Gains	2	1
Available-for-sale securities, Gross Unrealized Losses	(2)
Available-for-sale securities, Estimated Fair Value	3,558	603
Municipal bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Amortized Cost	37,257	39,661
Available-for-sale securities, Gross Unrealized Gains	83	211
Available-for-sale securities, Gross Unrealized Losses	(99)
Available-for-sale securities, Estimated Fair Value	$ 37,241	$ 39,872

Amount of accumulated pre-tax unrealized gain before deducting pre-tax unrealized loss on investments in available-for-sale debt securities impacting investments.

No definition available.

+ Details

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- Definition

Amount of accumulated pre-tax unrealized loss before deducting pre-tax unrealized gain on investments in available-for-sale debt securities impacting investments.

+ References

No definition available.

+ Details

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- Definition

This item represents the cost of debt 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.

+ References

No definition available.

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- Definition

Amount of investments in debt securities classified as available-for-sale, expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562

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