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Discontinued Operations - Narrative (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]      
Gain on asset sales and disposals $ 581 $ 6,498 $ 2,441
Plant, equipment and mineral rights funded with accounts payable or accrued liabilities $ 970 $ 0 0
Discontinued Operations, Held-for-sale      
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]      
Consideration received for sale of business     205,000
Gain on asset sales and disposals     13,100
Construction Aggregates | Discontinued Operations, Held-for-sale      
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]      
Capital expenditures     10,900
Plant, equipment and mineral rights funded with accounts payable or accrued liabilities     $ 900