Note 9 - Postretirement and Postemployment Benefits - Benefit Obligations and Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 26, 2021	Sep. 27, 2020
Liability (gain) loss due to Curtailment	$ (23,830)	$ 0
Other Postretirement Benefits Plan [Member]
Benefit obligation, beginning of year	47,637	11,752
Business combination	0	36,800
Service cost	207	500
Interest cost	429	869
Actuarial loss (gain)	(4,285)	(982)
Benefits paid, net of premiums received	(1,678)	(1,374)
Medicare Part D subsidies	58	72
Benefit obligation, end of year	18,538	47,637
Fair value of plan assets, beginning of year:	25,706	24,135
Business combination	0	0
Actual return on plan assets	1,534	1,594
Employer contributions	1,293	646
Benefits paid, net of premiums and Medicare Part D subsidies received	(1,795)	(1,077)
Benefits paid for active employees	64	(438)
One time asset transfer	0	846
Fair value of plan assets, end of year	26,802	25,706
Funded status	$ 8,264	$ (21,931)