Note 8 - Employee Post-employment Benefits (Details Textual) $ in Thousands		3 Months Ended
	Aug. 11, 2016	Aug. 30, 2016 USD ($)	Sep. 01, 2015 USD ($)	May 31, 2016 USD ($)
Pension Plan [Member] | Payroll and Related Costs [Member]
Defined Benefit Pension Plan Liabilities, Current		$ 2,500		$ 2,500
Pension Plan [Member] | Other Deferred Liabilities [Member]
Defined Benefit Pension Plan, Liabilities, Noncurrent		34,700		35,700
Pension Plan [Member]
Defined Benefit Plan, Amortization of Gains (Losses)		(338)	$ (628)
Post-retirement Medical and Life Benefits Plans [Member] | Payroll and Related Costs [Member]
Defined Benefit Pension Plan Liabilities, Current		100		100
Post-retirement Medical and Life Benefits Plans [Member] | Other Deferred Liabilities [Member]
Defined Benefit Pension Plan, Liabilities, Noncurrent		1,000		1,000
Retirement Plan [Member]
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year		100
Selling, General and Administrative Expense [Member] | Employee Severance [Member]
Closures and Impairments Expenses		300
Employee Severance [Member]
Employee-related Liabilities, Current		300		300
Closures and Impairments Expenses		1,700
Selling, General and Administrative Expenses [Member]
Defined Benefit Plan, Amortization of Gains (Losses)		400	700
Employee-related Liabilities, Current		$ 14,978		$ 14,561
Defined Benefit Pension Plans		3
Number of Restaurants Closed	95	99
Closures and Impairments Expenses		$ 30,192	$ 2,712