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Fair Value Measurements - Narrative (Details) - USD ($) | 12 Months Ended
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Jan. 26, 2020 | Jan. 27, 2019 | Jan. 28, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Cost-method investments, write down | $ 500,000 |  |
Available-for-sale, realized gain (loss) | (700,000) |  |
Transfers of financial assets or liabilities between levels | 0 | $ 0 |
Impairment of investments | $ 1,211,000 | 30,000,000 | $ 4,250,000
Fair value of investment |  | $ 0 |
Valuation Technique, Discounted Cash Flow | Measurement Input, Cap Rate |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |
Investment, measurement input |  | 38.80% |

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- Definition This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the cost method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment. + References No definition available. + Details
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- Definition Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27357-111563 + Details
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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=116654751&loc=SL75117539-209714 + Details
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- Definition Line items represent financial 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. + References No definition available. + Details
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- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
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