Note 8 - Pension Plans (Details Textual) - USD ($)	12 Months Ended
	Sep. 26, 2021	Sep. 27, 2020	Sep. 29, 2019
Pension Plan [Member]
Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year	$ 5,035,000
Defined Benefit Plan, Accumulated Benefit Obligation	384,187,000	$ 401,381,000
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation	384,187,000
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation	384,187,000
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets	$ 176,214,000
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	5.90%	6.00%	5.50%
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	$ 254,000
Liability, Defined Benefit Plan, Noncurrent, Total		$ 70,027,000
Pension Plan [Member] | U.S. Small Cap Value Equity Common/Collective Fund [Member]
Equity Securities, FV-NI, Current	7,236,000	5,500,000
Pension Plan [Member] | Global Equity Long/Short Common/Collective Hedge Fund-of-funds [Member]
Equity Securities, FV-NI, Current	8,371,000	7,096,000
Pension Plan [Member] | Global Equity Long/Short Common/Collective Hedge Fund-of-funds 2 [Member]
Equity Securities, FV-NI, Current	10,387,000	8,881,000
Other Pension Plan [Member]
Liability, Defined Benefit Plan, Noncurrent, Total	$ 996,000	$ 1,483,000