Investments - Sales and Maturities (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Oct. 23, 2021	Oct. 24, 2020	Oct. 23, 2021	Oct. 24, 2020
Sales of marketable securities
Proceeds from sales	$ 11,938	$ 3,292	$ 21,653	$ 17,017
Gross realized gains	287	184	554	310
Gross realized losses	(325)	$ (8)	(336)	$ (26)
Fair value of available-for-sale securities by contractual maturity
Within one year	16,777		16,777
Within two to five years	15,668		15,668
Within six to ten years	975		975
Thereafter	1,637		1,637
Total	$ 35,057		$ 35,057

No definition available.

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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next rolling fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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No definition available.

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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing after rolling tenth fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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No definition available.

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Fair value of investment in debt security, measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in rolling sixth through tenth fiscal year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Fair value of investment in debt security, measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next rolling fiscal year through fifth year following latest fiscal year. For interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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- Definition

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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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), excluding other-than-temporary impairment (OTTI).

+ References

No definition available.

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Amount of realized 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/2003/role/disclosureRef
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Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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