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Accrued Mining and Landfill Reclamation (Tables)
 12 Months Ended
Jan. 02, 2021
Asset Retirement Obligations [Line Items]  
Activity for Asset Retirement Obligations The following table presents the activity for the asset retirement obligations for the years ended January 2, 2021 and December 28, 2019: 
 20202019
Beginning balance$36,676 $30,999 
Acquired obligations861 805 
Change in cost estimate6,523 4,468 
Settlement of reclamation obligations(3,095)(1,812)
Accretion expense2,638 2,216 
Ending balance$43,603 $36,676 
Summit Materials, LLC  
Asset Retirement Obligations [Line Items]  
Activity for Asset Retirement Obligations The following table presents the activity for the asset retirement obligations for the years ended January 2, 2021 and December 28, 2019:
 20202019
Beginning balance$36,676 $30,999 
Acquired obligations861 805 
Change in cost estimate6,523 4,468 
Settlement of reclamation obligations(3,095)(1,812)
Accretion expense2,638 2,216 
Ending balance$43,603 $36,676