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Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 30, 2017	Nov. 21, 2017	Jan. 19, 2017	Dec. 31, 2016
Debt
Total debt	$ 1,832,455			$ 1,536,065
Current portion of long-term debt	4,765			6,500
Long-term debt	1,827,690			1,529,565
Gross amount	1,835,375
Debt discount	2,920
Summit Materials, LLC
Debt
Total debt	1,832,455			1,536,065
Current portion of long-term debt	4,765			6,500
Long-term debt	1,827,690			1,529,565
Gross amount	1,835,375
Debt discount	2,920
Term Loan, due 2022 \| Summit Materials, LLC
Debt
Gross amount			$ 640,300
Term Loan, due 2024
Debt
Total debt	633,805			637,658
Gross amount	635,400			640,300
Debt discount	1,600			2,600
Term Loan, due 2024 \| Summit Materials, LLC
Debt
Total debt	633,805			637,658
Gross amount	635,400	$ 635,400		640,300
Debt discount	1,600			2,600
8 1/2% Senior Notes, due 2022
Debt
Total debt	$ 250,000			250,000
Debt instrument interest rate (as a percent)	8.50%
8 1/2% Senior Notes, due 2022 \| Summit Materials, LLC
Debt
Total debt	$ 250,000			$ 250,000
Debt instrument interest rate (as a percent)	8.50%			8.50%
6 1/8% Senior Notes, due 2023
Debt
Total debt	$ 648,650			$ 648,407
Gross amount	650,000			650,000
Debt discount	$ 1,400			$ 1,600
Debt instrument interest rate (as a percent)	6.125%			6.125%
6 1/8% Senior Notes, due 2023 \| Summit Materials, LLC
Debt
Total debt	$ 648,650			$ 648,407
Gross amount	650,000			650,000
Debt discount	$ 1,400			$ 1,600
Debt instrument interest rate (as a percent)	6.125%			6.125%
5 1/8% Senior Notes, due 2025
Debt
Total debt	$ 300,000
Debt instrument interest rate (as a percent)	5.125%
5 1/8% Senior Notes, due 2025 \| Summit Materials, LLC
Debt
Total debt	$ 300,000
Debt instrument interest rate (as a percent)	5.125%