Fair Value Measurements - Investment Impairments and Credit Loss Reserves (Details) - USD ($)	3 Months Ended		6 Months Ended
	Aug. 01, 2021	Jul. 26, 2020	Aug. 01, 2021	Jul. 26, 2020	Jan. 31, 2021	Jan. 26, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Credit loss reserve for held-to-maturity debt securities and available for sale debt securities	$ 4,100,000		$ 4,100,000		$ 3,400,000
Increase in credit loss reserve for available-for-sale and held-to-maturity debt securities	$ 500,000	$ 0	$ 700,000	$ 2,400,000
Impairment on non-marketable equity securities		$ 1,700,000		$ 2,900,000
ASU 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Credit loss reserve on held-to-maturity securities						$ 400,000