DEBT - Schedule of Debt (Details) - USD ($) $ in Thousands	Apr. 02, 2022	Jan. 01, 2022
Debt Instrument [Line Items]
Total debt	$ 1,607,767	$ 1,609,298
Current portion of debt	6,354	6,354
Long-term debt	1,601,413	1,602,944
Gross amount	1,608,372
Debt discount	605
Summit Materials, LLC
Debt Instrument [Line Items]
Total debt	1,607,767	1,609,298
Current portion of debt	6,354	6,354
Long-term debt	1,601,413	1,602,944
Gross amount	1,608,372
Debt discount	605
Senior Notes \| Term Loan, due 2024
Debt Instrument [Line Items]
Total debt	607,767	609,298
Gross amount	608,400	610,000
Debt discount	600	700
Senior Notes \| 6 1/2% Senior Notes, due 2027
Debt Instrument [Line Items]
Total debt	$ 300,000	300,000
Debt instrument interest rate (as a percent)	6.50%
Senior Notes \| 5 1/4% Senior Notes Due 2029
Debt Instrument [Line Items]
Total debt	$ 700,000	700,000
Debt instrument interest rate (as a percent)	5.25%
Senior Notes \| Summit Materials, LLC \| Term Loan, due 2024
Debt Instrument [Line Items]
Total debt	$ 607,767	609,298
Gross amount	608,400	610,000
Debt discount	600	700
Senior Notes \| Summit Materials, LLC \| 6 1/2% Senior Notes, due 2027
Debt Instrument [Line Items]
Total debt	$ 300,000	300,000
Debt instrument interest rate (as a percent)	6.50%
Senior Notes \| Summit Materials, LLC \| 5 1/4% Senior Notes Due 2029
Debt Instrument [Line Items]
Total debt	$ 700,000	$ 700,000
Debt instrument interest rate (as a percent)	5.25%

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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