REVENUE RECOGNITION - Summary of Accounts Receivable, Net (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 26, 2020	Dec. 28, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 231,663	$ 191,672
Construction contract receivables	62,183	47,966
Retention receivables	18,501	17,808
Receivables from related parties	1,918	1,596
Accounts receivable	314,265	259,042
Less: Allowance for doubtful accounts	(4,888)	(5,786)
Accounts receivable, net	$ 309,377	253,256
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
General collection and billing period for retention receivables	1 year
Summit Materials, LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 231,663	191,672
Construction contract receivables	62,183	47,966
Retention receivables	18,501	17,808
Receivables from related parties	1,918	1,596
Accounts receivable	314,265	259,042
Less: Allowance for doubtful accounts	(4,888)	(5,786)
Accounts receivable, net	$ 309,377	$ 253,256
Summit Materials, LLC \| Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
General collection and billing period for retention receivables	1 year

The general collection and billing period for retention receivables.

No definition available.

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Amounts earned by entity but held by customers until projects have been fully completed or near completion and are expected to be billed and collected within one year of the balance sheet date (or the normal operating cycle, whichever is longer).

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- Definition

Trade receivable amounts due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer) for goods or services.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount, before allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

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Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

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For an unclassified balance sheet, amount of receivables arising from transactions with related parties.

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Amount of allowance for credit loss on accounts receivable, classified as current.

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Amounts due for billed services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the Company and, at a minimum, one other party. An example would be amounts billed to customers under contracts or programs but not paid as of the balance sheet date.

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