Pensions (Details) - USD ($) | 12 Months Ended |
Sep. 29, 2019 | Sep. 30, 2018 | Sep. 24, 2017 | Sep. 25, 2016 |
Pension Plans, Defined Benefit [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months | | $ 12,000 | | |
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate | | 4.00% | 4.00% | 4.00% |
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate | | 4.00% | 4.00% | |
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Gain (Loss), before Tax | $ 1,136,000 | $ (31,988,000) | $ (43,550,000) | |
Liability, Defined Benefit Plan, Noncurrent | | (25,276,000) | (41,883,000) | |
Defined Benefit Plan, Benefit Obligation | | 176,531,000 | 191,645,000 | $ 202,158,000 |
Defined Benefit Plan, Accumulated Benefit Obligation | | | 191,645,000 | |
Defined Benefit Plan, Service Cost | | 48,000 | 84,000 | 197,000 |
Defined Benefit Plan, Interest Cost | | 5,754,000 | 5,394,000 | 6,061,000 |
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) | | (9,464,000) | (4,241,000) | |
Defined Benefit Plan, Plan Assets, Administration Expense | | (2,571,000) | (2,340,000) | |
Defined Benefit Plan, Plan Assets, Contributions by Employer | 650,000 | 4,940,000 | 0 | |
Defined Benefit Plan, Expected Return (Loss) on Plan Assets | | (7,933,000) | (7,878,000) | (8,698,000) |
Defined Benefit Plan, Amortization of Net Loss | | (2,025,000) | 2,947,000 | 2,397,000 |
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit) | | (136,000) | (136,000) | (136,000) |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) | | (242,000) | 411,000 | (179,000) |
Defined Benefit Plan, Fair Value of Plan Assets | | 151,255,000 | 149,762,000 | $ 149,131,000 |
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) | | 10,576,000 | 14,721,000 | |
Defined Benefit Plan, Plan Assets, Benefits Paid | | 11,452,000 | 11,750,000 | |
Defined Benefit Plan, Funded (Unfunded) Status of Plan | | (25,276,000) | (41,883,000) | |
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax | | (31,882,000) | (43,307,000) | |
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Prior Service Cost, before Tax | $ (100,000) | 106,000 | 243,000 | |
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax | | $ (31,882,000) | $ (43,307,000) | |
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets | | 6.00% | 6.00% | 6.00% |
Defined Benefit Plan, Expected Future Benefit Payment, Year Two | | $ 12,000 | | |
Defined Benefit Plan, Expected Future Benefit Payment, Year Three | | 12,000 | | |
Defined Benefit Plan, Expected Future Benefit Payment, Year Four | | 12,000 | | |
Defined Benefit Plan, Expected Future Benefit Payment, Year Five | | 12,000 | | |
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter | | $ 57,000 | | |
Pension Plans, Defined Benefit [Member] | Equity Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Actual Plan Asset Allocations | | 50.00% | 50.00% | |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | | 5000.00% | | |
Pension Plans, Defined Benefit [Member] | Fixed Income Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Alternative Investment, Fair Value Disclosure | | $ 0 | $ 14,711,000 | |
Defined Benefit Plan, Actual Plan Asset Allocations | | 32.00% | 33.00% | |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | | 3500.00% | | |
Pension Plans, Defined Benefit [Member] | Fixed Income Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | $ 25,673,390 | $ 26,015,000 | |
Pension Plans, Defined Benefit [Member] | Fixed Income Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 22,523,021 | 8,266,000 | |
Pension Plans, Defined Benefit [Member] | Fixed Income Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Pension Plans, Defined Benefit [Member] | US Treasury Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Alternative Investment, Fair Value Disclosure | | $ 0 | $ 0 | |
Defined Benefit Plan, Actual Plan Asset Allocations | | 4.00% | 4.00% | |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | | 500.00% | | |
Pension Plans, Defined Benefit [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | $ 6,534,531 | $ 6,553,000 | |
Pension Plans, Defined Benefit [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Pension Plans, Defined Benefit [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Pension Plans, Defined Benefit [Member] | Hedge Funds [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Alternative Investment, Fair Value Disclosure | | $ 15,766,606 | $ 19,067,000 | |
Defined Benefit Plan, Actual Plan Asset Allocations | | 10.00% | 12.00% | |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | | 1000.00% | | |
Pension Plans, Defined Benefit [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | $ 0 | $ 0 | |
Pension Plans, Defined Benefit [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Pension Plans, Defined Benefit [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Pension Plans, Defined Benefit [Member] | Cash and Cash Equivalents [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Alternative Investment, Fair Value Disclosure | | $ 0 | $ 0 | |
Defined Benefit Plan, Actual Plan Asset Allocations | | 4.00% | 1.00% | |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | | 0.00% | | |
Pension Plans, Defined Benefit [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | $ 5,536,967 | $ 1,882,000 | |
Pension Plans, Defined Benefit [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Pension Plans, Defined Benefit [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Other Plans [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Funded (Unfunded) Status of Plan | | 1,469,000 | 1,766,000 | |
Funded Status of Other Plans Recognized In Other Liabilities | | 113,000 | | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment | | (2,031,000) | $ (3,741,000) | $ 0 |
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months | | $ 1,302,000 | | |
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate | | 3.00% | 3.00% | 4.00% |
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate | | 4.00% | 3.00% | |
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Gain (Loss), before Tax | | $ 12,224,000 | $ 12,304,000 | |
Liability, Defined Benefit Plan, Noncurrent | | 0 | (2,061,000) | |
Defined Benefit Plan, Benefit Obligation | | 11,756,000 | 15,667,000 | $ 22,511,000 |
Defined Benefit Plan, Service Cost | | 0 | 13,000 | 0 |
Defined Benefit Plan, Interest Cost | | 365,000 | 412,000 | 1,000 |
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) | | (1,054,000) | (627,000) | |
Defined Benefit Plan, Plan Assets, Contributions by Employer | | 422,000 | 755,000 | |
Defined Benefit Plan, Expected Return (Loss) on Plan Assets | | (1,080,000) | (1,056,000) | (1,000) |
Defined Benefit Plan, Amortization of Net Loss | | 984,000 | (987,000) | (1,093) |
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit) | | (785,000) | (1,459,000) | (1,459) |
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) | | (4,515,000) | (6,818,000) | (3,000) |
Defined Benefit Plan, Fair Value of Plan Assets | | 24,647,000 | 24,626,000 | $ 24,123,000 |
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) | | 2,106,000 | 2,112,000 | |
Defined Benefit Plan, Plan Assets, Benefits Paid | | 1,399,000 | 1,527,000 | |
Defined Benefit Plan, Funded (Unfunded) Status of Plan | | 12,891,000 | 8,959,000 | |
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax | | 17,917,000 | 18,782,000 | |
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Prior Service Cost, before Tax | | 5,693,000 | 6,478,000 | |
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax | | $ 17,917,000 | $ 18,782,000 | |
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets | | 5.00% | 5.00% | 5.00% |
Defined Benefit Plan, Expected Future Benefit Payment, Year Two | | $ 1,276,000 | | |
Defined Benefit Plan, Expected Future Benefit Payment, Year Three | | 1,241,000 | | |
Defined Benefit Plan, Expected Future Benefit Payment, Year Four | | 1,198,000 | | |
Defined Benefit Plan, Expected Future Benefit Payment, Year Five | | 1,147,000 | | |
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter | | $ 4,794,000 | | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Actual Plan Asset Allocations | | 0.00% | 0.00% | |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | | 2000.00% | | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed Income Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Alternative Investment, Fair Value Disclosure | | $ 0 | $ 0 | |
Defined Benefit Plan, Actual Plan Asset Allocations | | 100.00% | 100.00% | |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | | 7000.00% | | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed Income Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | $ 19,185,439 | $ 19,548,000 | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed Income Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fixed Income Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Hedge Funds [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Alternative Investment, Fair Value Disclosure | | $ 3,615,724 | $ 3,343,000 | |
Defined Benefit Plan, Actual Plan Asset Allocations | | 0.00% | 0.00% | |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | | 1000.00% | | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | $ 0 | $ 0 | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Cash and Cash Equivalents [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Alternative Investment, Fair Value Disclosure | | $ 0 | $ 0 | |
Defined Benefit Plan, Actual Plan Asset Allocations | | 0.00% | 0.00% | |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | | 0.00% | | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | $ 241,761 | $ 0 | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Other Postretirement Benefit Plans, Defined Benefit [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Domestic Equity Securities [Member] | Pension Plans, Defined Benefit [Member] | Equity Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Alternative Investment, Fair Value Disclosure | | 10,045,418 | 0 | |
Domestic Equity Securities [Member] | Pension Plans, Defined Benefit [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 12,573,102 | 10,484,000 | |
Domestic Equity Securities [Member] | Pension Plans, Defined Benefit [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 40,082,579 | 49,483,000 | |
Domestic Equity Securities [Member] | Pension Plans, Defined Benefit [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
Domestic Equity Securities [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Alternative Investment, Fair Value Disclosure | | 819,683 | 0 | |
Domestic Equity Securities [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 2,589,046 | 3,479,000 | |
Domestic Equity Securities [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 741,000 | |
Domestic Equity Securities [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
International Equity Securities [Member] | Pension Plans, Defined Benefit [Member] | Equity Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Alternative Investment, Fair Value Disclosure | | 0 | 0 | |
International Equity Securities [Member] | Pension Plans, Defined Benefit [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 7,069,800 | 7,290,000 | |
International Equity Securities [Member] | Pension Plans, Defined Benefit [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 7,560,034 | 8,047,000 | |
International Equity Securities [Member] | Pension Plans, Defined Benefit [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 0 | 0 | |
International Equity Securities [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity Securities [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Alternative Investment, Fair Value Disclosure | | 0 | 0 | |
International Equity Securities [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 680,940 | 800,000 | |
International Equity Securities [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | 780,425 | 1,051,000 | |
International Equity Securities [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | | | |
Defined Benefit Plan Disclosure [Line Items] | | | | |
Defined Benefit Plan, Fair Value of Plan Assets | | $ 0 | $ 0 | |