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Investments - Narrative (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
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Oct. 28, 2018 | Oct. 29, 2017 | Jan. 27, 2019 | Jan. 28, 2018 | Jan. 29, 2017
Investments [Abstract] |  |  |  |  |
Impairment of investments | $ 30,000 | $ 4,300 | $ 30,000 | $ 4,250 | $ 0

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- Definition Amount of impairment loss on investment in equity security without readily determinable fair value. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84241550&loc=SL75117539-209714 + Details
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- References No definition available. + Details
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