INVENTORIES - Components of Inventories (Details) - USD ($) $ in Thousands	Apr. 02, 2022	Jan. 01, 2022
Inventory [Line Items]
Aggregate stockpiles	$ 123,981	$ 130,640
Finished goods	37,882	22,690
Work in process	6,974	8,277
Raw materials	18,172	19,153
Total	187,009	180,760
Summit Materials, LLC
Inventory [Line Items]
Aggregate stockpiles	123,981	130,640
Finished goods	37,882	22,690
Work in process	6,974	8,277
Raw materials	18,172	19,153
Total	$ 187,009	$ 180,760

Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

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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 after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount before last-in first-out (LIFO) and valuation reserves of ore stockpile material contained on a leach pad, for example, but not limited to, copper or gold ore.

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Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of unprocessed items to be consumed in the manufacturing or production process.

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Carrying amount, net of reserves and adjustments, as of the balance sheet date of merchandise or goods which are partially completed. This inventory is generally comprised of raw materials, labor and factory overhead costs, which require further materials, labor and overhead to be converted into finished goods, and which generally require the use of estimates to determine percentage complete and pricing.

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