Investments - Summary Of Investments (Details) (USD $) In Thousands, unless otherwise specified	Apr. 26, 2015	Jan. 25, 2015
Investment [Line Items]
Available-for-sale securities, market value	$ 23,277	$ 23,271
Available-for-sale investments, adjusted cost	23,277	23,271
Available-for-sale investments, gross unrealized gain	0	0
Cash Equivalents [Member]
Investment [Line Items]
Available-for-sale securities, market value	23,277	23,271
Available-for-sale investments, adjusted cost	23,277	23,271
Available-for-sale investments, gross unrealized gain	$ 0	$ 0

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

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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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.2)

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- Definition

Amount of debt securities categorized neither as held-to-maturity nor trading.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

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