Note 7 - Pension, Postretirement and Postemployment Defined Benefit Plans - Net Periodic Cost (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 29, 2020	Mar. 31, 2019	Mar. 29, 2020	Mar. 31, 2019
Pension Plan [Member]
Service cost for benefits earned during the period	$ 103	$ 9	$ 111	$ 18
Interest cost on projected benefit obligation	1,420	1,641	2,651	3,282
Expected return on plan assets	(2,321)	(2,018)	(4,272)	(4,036)
Amortization of net loss	792	284	1,584	568
Amortization of prior service benefit	(2)	(25)	(4)	(50)
Pension benefit	(8)	(109)	70	(218)
Postretirement Health Coverage [Member]
Service cost for benefits earned during the period	36		36
Interest cost on projected benefit obligation	110	103	177	206
Expected return on plan assets	(265)	(270)	(530)	(540)
Amortization of net loss	(186)	(244)	(372)	(488)
Amortization of prior service benefit	(161)	(181)	(322)	(362)
Pension benefit	$ (466)	$ (592)	$ (1,011)	$ (1,184)