REVENUE RECOGNITION - By Product (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2023	Jul. 02, 2022	Jul. 01, 2023	Jul. 02, 2022
Revenue from External Customer [Line Items]
Total revenue	$ 729,150	$ 686,554	$ 1,164,538	$ 1,107,501
Aggregates
Revenue from External Customer [Line Items]
Total revenue	182,512	161,480	326,165	284,873
Cement
Revenue from External Customer [Line Items]
Total revenue	103,607	86,815	152,620	129,369
Ready-mix concrete
Revenue from External Customer [Line Items]
Total revenue	199,570	183,357	338,348	340,920
Asphalt
Revenue from External Customer [Line Items]
Total revenue	91,809	94,141	118,444	111,279
Paving and related services
Revenue from External Customer [Line Items]
Total revenue	89,374	98,610	116,558	129,220
Other
Revenue from External Customer [Line Items]
Total revenue	62,278	62,151	112,403	111,840
Summit Materials, LLC
Revenue from External Customer [Line Items]
Total revenue	729,150	686,554	1,164,538	1,107,501
Summit Materials, LLC | Aggregates
Revenue from External Customer [Line Items]
Total revenue	182,512	161,480	326,165	284,873
Summit Materials, LLC | Cement
Revenue from External Customer [Line Items]
Total revenue	103,607	86,815	152,620	129,369
Summit Materials, LLC | Ready-mix concrete
Revenue from External Customer [Line Items]
Total revenue	199,570	183,357	338,348	340,920
Summit Materials, LLC | Asphalt
Revenue from External Customer [Line Items]
Total revenue	91,809	94,141	118,444	111,279
Summit Materials, LLC | Paving and related services
Revenue from External Customer [Line Items]
Total revenue	89,374	98,610	116,558	129,220
Summit Materials, LLC | Other
Revenue from External Customer [Line Items]
Total revenue	$ 62,278	$ 62,151	$ 112,403	$ 111,840