Note 8 - Employee Post-employment Benefits (Tables)
 3 Months Ended
Aug. 30, 2016
Notes Tables  
Schedule of Net Benefit Costs [Table Text Block]
   
Pension Plans
   
Thirteen weeks ended
   
August 30, 2016
  
September 1, 2015
Service cost
 
$
6
 
 
$
230
 
 
Interest cost
 
 
420
 
 
 
599
 
 
Expected return on plan assets
 
 
(
91
)
 
 
(
103
)
 
Recognized actuarial loss
 
 
338
 
 
 
628
 
 
Net periodic benefit cost
 
$
673
 
 
$
1,354
 
 
   
Postretirement Medical and Life Benefits
   
Thirteen weeks ended
   
August 30, 2016
  
September 1, 2015
Service cost
 
$
1
 
 
$
1
 
 
Interest cost
 
 
9
 
 
 
12
 
 
Recognized actuarial loss
 
 
17
 
 
 
32
 
 
Net periodic benefit cost
 
$
2
7
 
 
$
45
 
 
Schedule of Unpaid Employee Separation Obligations Included in Accrued Payroll and Related Costs [Table Text Block]
Balance at
May 31, 2016
 
$
317
 
Employee severance and unused vacation accruals
 
 
2,020
 
Cash payments
 
 
(
2,068
)
Balance at
August 30, 2016
 
$
269