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Financial Instruments and Fair Value - Additional Information (Detail) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Oct. 31, 2022 USD ($) Security | Oct. 31, 2021 USD ($) | Oct. 31, 2022 USD ($) Security | Oct. 31, 2021 USD ($)
Investments Debt And Equity Securities [Abstract] |  |  |  |
Number of debt securities with unrealized losses for more than twelve months | Security | 0 |  | 0 |
Interest income | $ 0.7 | $ 0.7 | $ 0.8 | $ 0.8
Realized gains, net | $ 0.7 | $ 0.7 | $ 1.7 | $ 1.7

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- Definition Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without an allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 4 -Subparagraph (b)(3) -URI https://asc.fasb.org/extlink&oid=124269663&loc=SL82922888-210455 + Details
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- Definition Amount of realized gain 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/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27357-111563 + Details
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- Definition Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.7(b)) -URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (c) -URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599 + Details
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