Investment Securities (Narrative) (Details) - USD ($)	12 Months Ended
	May 28, 2022	May 29, 2021	May 30, 2020
Investments Securities [Abstract]
Proceeds from sale of available-for-sale securities, current	$ 92,700,000	$ 129,100,000	$ 204,300,000
Proceeds from sale of available-for-sale securities, noncurrent	4,900,000	54,000	1,200,000
Gross realized gains on sales of available-for-sale securities, current	181,000	456,000	278,000
Gross realized gains on sales of available-for-sale securities, noncurrent	2,200,000	611,000
Gross realized losses on sales of available-for-sale securities, current	76,000	19,000	6,000
Gross realized losses on sales of available-for-sale securities, noncurrent	0	0	$ 0
Allowance for credit losses	$ 0	$ 0