Investment Securities (Schedule Of Investment Securities) (Details) - USD ($) $ in Thousands	Feb. 29, 2020	Jun. 01, 2019
Current Assets
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 80,390	$ 249,875
Unrealized Gains	475	315
Unrealized Losses	2	9
Estimated Fair Value	80,863	250,181
Noncurrent Assets
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,994	2,331
Unrealized Gains	661	1,026
Unrealized Losses	0	0
Estimated Fair Value	2,655	3,357
US government and agency obligations \| Current Assets
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		30,896
Unrealized Gains		78
Unrealized Losses		0
Estimated Fair Value		30,974
Municipal bonds \| Current Assets
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	18,862	50,220
Unrealized Gains	134	133
Unrealized Losses	0	0
Estimated Fair Value	18,996	50,353
Commercial paper \| Current Assets
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		9,953
Unrealized Gains		0
Unrealized Losses		8
Estimated Fair Value		9,945
Corporate bonds \| Current Assets
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	59,329	147,068
Unrealized Gains	329	94
Unrealized Losses	0	0
Estimated Fair Value	59,658	147,162
Certificates of deposits \| Current Assets
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,003	6,149
Unrealized Gains	0	0
Unrealized Losses	2	1
Estimated Fair Value	1,001	6,148
Asset backed securities \| Current Assets
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,196	5,589
Unrealized Gains	12	10
Unrealized Losses	0	0
Estimated Fair Value	1,208	5,599
Mutual funds \| Noncurrent Assets
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,994	2,331
Unrealized Gains	661	1,026
Unrealized Losses	0	0
Estimated Fair Value	$ 2,655	$ 3,357

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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- Definition

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

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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.

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