Note 8 - Postretirement and Postemployment Benefits - Amounts Recognized in Accumulated Other Comprehensive Income (Loss) (Details) - Other Postretirement Benefits Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Sep. 27, 2020	Sep. 29, 2019
Unrecognized net actuarial gain	$ 4,826	$ 4,970
Unrecognized prior service benefit	9,443	9,848
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax, Total	$ 14,269	$ 14,818