Note 8 - Pension Plans - Amounts Recognized in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 26, 2021	Sep. 27, 2020
Unrecognized net actuarial gain (loss)	$ 36,965	$ (41,344)
Pension Plan [Member]
Unrecognized prior service benefit	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax, Total	$ 36,965	$ (41,344)

Amount, before tax, after reclassification adjustment, of (increase) decrease in accumulated other comprehensive income for defined benefit plan.

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