Line items represent reporting 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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
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+ 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 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Investments - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Investments - Narrative (Details) - USD ($) $ in Thousands	Jan. 31, 2016	Jan. 25, 2015	Jan. 26, 2014
Investment [Line Items]
Investment in privately traded companies, cash consideration	$ 14,630	$ 7,148	$ 2,500
Total equity investment in privately traded companies	$ 20,200
Minimum
Investment [Line Items]
Investment maturity period	3 months
Temporary investments \| Minimum
Investment [Line Items]
Investment maturity period	3 months
Temporary investments \| Maximum
Investment [Line Items]
Investment maturity period	12 months
Long-term investments \| Minimum
Investment [Line Items]
Investment maturity period	12 months
Other assets
Investment [Line Items]
Total equity investment in privately traded companies	$ 20,200	$ 12,100
Jariet Technologies Inc [Member]
Investment [Line Items]
Total equity investment in privately traded companies	0
Impairment of investment	$ 600