REVENUE RECOGNITION - Summary of Accounts Receivable, Net (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 28, 2019	Dec. 29, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 251,426	$ 157,601
Construction contract receivables	71,903	47,994
Retention receivables	17,227	15,010
Receivables from related parties	1,783	629
Accounts receivable	342,339	221,234
Less: Allowance for doubtful accounts	(5,279)	(6,716)
Accounts receivable, net	$ 337,060	214,518
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	$ 251,426	157,601
Construction contract receivables	71,903	47,994
Retention receivables	17,227	15,010
Receivables from related parties	1,783	629
Accounts receivable	342,339	221,234
Less: Allowance for doubtful accounts	(5,279)	(6,716)
Accounts receivable, net	$ 337,060	$ 214,518
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.

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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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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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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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