Note 7 - Pension Plans - Benefit Obligations and Plan Assets (Details) - Pension Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 30, 2018
Benefit obligation, beginning of year	$ 192,369	$ 176,531
Business combination	195,834	0
Service cost	1,361	36	$ 48
Interest cost	7,577	6,563	5,754
Actuarial loss (gain)	20,525	20,687
Benefits paid	(16,246)	(11,448)
Administrative expenses paid	(39)	0
Benefit obligation, end of year	401,381	192,369	176,531
Fair value of plan assets, beginning of year:	146,999	151,255
Business combination	152,331	0
Actual return on plan assets	44,933	8,705
Benefits paid	(16,246)	(11,448)
Administrative expenses paid	(2,794)	(2,163)
Employer contributions	6,131	650
Fair value of plan assets, end of year	331,354	146,999	$ 151,255
Funded status	$ (70,027)	$ (45,370)