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Benefit Plans - Contributions and Benefit Payments, Multiemployer Plan, 401(k) Plans and UMWA Benefit Plans (Details) $ in Thousands | 12 Months Ended
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Dec. 26, 2020 USD ($) bargain_agreement | Dec. 28, 2019 USD ($) | Dec. 29, 2018 USD ($)
IAM Plan Trusts [Abstract] |  |  |
Number of collective bargaining agreements | bargain_agreement | 2 |  |
Multiemployer plan, contributions | $ 1,200 | $ 1,200 | $ 1,300
Maximum percentage of employer contributions (less than) | 5.00% |  |
Multiemployer plans, funded status (as a percent) | 80.00% | 89.00% |
401 (k) Plan [Abstract] |  |  |
Compensation expense for the Company's matching contribution | $ 5,700 | $ 5,400 | 5,100
Contributions to UMWA 1992 Benefit Plan | $ 57 | $ 223 | $ 153

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- Definition Amount of contributions to the United Mine Workers of America 1992 Benefit Plan. + References No definition available. + Details
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- Definition The maximum percentage of employer contributions related to a defined pension plan or trust during the period. + References No definition available. + Details
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- Definition Amount of cost for defined contribution plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
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- Definition Amount of cost for employer contribution to multiemployer plan. Multiemployer plan includes, but is not limited to, pension plan determined to be individually significant and insignificant and other postretirement benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=35742348&loc=SL14450788-114948 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 35 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=29639808&loc=d3e29008-114946 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450702-114947 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 9 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450691-114947 + Details
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