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Selected Quarterly Financial Data - Narrative (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 26, 2020 | Sep. 26, 2020 | Jun. 27, 2020 | Mar. 28, 2020 | Dec. 28, 2019 | Sep. 28, 2019 | Jun. 29, 2019 | Mar. 30, 2019 | Dec. 26, 2020 | Dec. 28, 2019 | Dec. 29, 2018
Quarterly Financial Information Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |
Acquisition related costs | $ 700 | $ 300 | $ 100 | $ 1,200 | $ 1,900 | $ 3,200 | $ 1,500 | $ 2,400 |  |  |
Restructuring, impairment and other costs | $ 800 | 1,300 | 1,800 |  | 2,100 | $ 2,500 | 5,700 |  | $ 41,716 | $ 13,033 | $ 12,583
Impairment charges |  | $ 100 |  |  | 4,200 |  | 200 | 2,800 | 36,078 | 322 | $ 2,218
Other asset impairment charges |  |  | 33,800 | 1,900 |  |  |  |  |  |  |
Asset retirement expense |  |  | 200 |  |  |  |  |  |  |  |
Increase to coal mining reserve |  |  | $ 1,800 |  |  |  |  |  |  |  |
Restructuring costs |  |  |  | $ 4,000 |  |  |  | 2,700 |  |  |
Benefit for previously unrecognized tax benefits in respect of which the statute of limitation has expired |  |  |  |  | $ 3,300 |  |  |  | $ 103 | $ 2,758 |
Loss on sale of building |  |  |  |  |  |  | $ 400 |  |  |  |
Loss on disposal of business |  |  |  |  |  |  |  | 2,600 |  |  |
Gain related to acquisition of Monolith |  |  |  |  |  |  |  | $ 300 |  |  |

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- Definition Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2420-110228 + Details
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- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e1043-128460 + Details
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- Definition In a business combination achieved in stages, this element represents the amount of gain recognized by the entity as a result of remeasuring to fair value the equity interest in the acquiree it held before the business combination. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (g)(2) -URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463 + Details
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- Definition Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 + Details
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- Definition The increase (decrease) during the reporting period in the value of coal held in inventory. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 + Details
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- Definition The charge against earnings resulting from the write down of long lived assets other than goodwill due to the difference between the carrying value and lower fair value. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 + Details
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