Retirement Plans (Postemployment Severance Plan And Defined Contribution Plan) (Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jul. 31, 1996	May 27, 2018	May 28, 2017	May 29, 2016	May 29, 2005
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial losses on postemployment severance costs		$ 900,000	$ (100,000)
Defined benefit plan, required minimum age (in years)		21 years
Defined benefit plan, minimum period to perform service requirement (years)		1 year
Percentage of employer contribution (percentage)		6.00%
Defined contribution plan, annual contributions per employee, percent		1.50%
Defined benefit plan net assets		$ 829,000,000	753,700,000
Defined contribution plan, expense recognized		19,600,000	3,700,000	$ 15,100,000
Amounts payable to highly compensated employees under non-qualified deferred compensation plan		227,900,000	210,300,000
ESOP borrowings from at variable interest rate	$ 16,900,000
ESOP's debt		900,000
Additional shares acquired from common stock (shares)					50,000.00
Dividends received from employer		500,000	800,000	700,000
Contributions received from employer		$ 100,000	$ 100,000	$ 100,000
Common shares held in ESOP (shares)		2,100,000
ESOP, allocated shares (shares)		1,900,000
ESOP, suspense shares (shares)		200,000
Additional Loan
Defined Benefit Plan Disclosure [Line Items]
ESOP borrowings from at variable interest rate					$ 1,600,000
ESOP's debt		$ 1,000,000
Minimum
Defined Benefit Plan Disclosure [Line Items]
Employer contribution, per dollar		0.25
Maximum
Defined Benefit Plan Disclosure [Line Items]
Employer contribution, per dollar		$ 1.20
Employee Stock Ownership Plan
Defined Benefit Plan Disclosure [Line Items]
Variable rate of interest (percentage)		1.90%
Maturity date of debt		Dec. 01, 2019
Employee Stock Ownership Plan | Additional Loan
Defined Benefit Plan Disclosure [Line Items]
Variable rate of interest (percentage)		2.34%