Note 8 - Postretirement and Postemployment Benefits - Effect if One Percentage Point Change in Assumed Heath Care Cost Trend Rates (Details) - Other Postretirement Benefits Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Sep. 27, 2020	Sep. 29, 2019
Effect on net periodic postretirement benefit, increase	$ 454
Effect on net periodic postretirement benefit, decrease		$ (344)
Effect on postretirement benefit obligation, increase	$ 6,524
Effect on postretirement benefit obligation, decrease		$ (5,216)