REVENUE RECOGNITION - By Product (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 02, 2022	Apr. 03, 2021
Revenue from External Customer [Line Items]
Total revenue	$ 420,947	$ 427,844
Aggregates
Revenue from External Customer [Line Items]
Total revenue	123,393	117,388
Cement
Revenue from External Customer [Line Items]
Total revenue	42,554	38,139
Ready-mix concrete
Revenue from External Customer [Line Items]
Total revenue	157,563	158,233
Asphalt
Revenue from External Customer [Line Items]
Total revenue	17,138	28,375
Paving and related services
Revenue from External Customer [Line Items]
Total revenue	30,610	43,215
Other
Revenue from External Customer [Line Items]
Total revenue	49,689	42,494
Summit Materials, LLC
Revenue from External Customer [Line Items]
Total revenue	420,947	427,844
Summit Materials, LLC | Aggregates
Revenue from External Customer [Line Items]
Total revenue	123,393	117,388
Summit Materials, LLC | Cement
Revenue from External Customer [Line Items]
Total revenue	42,554	38,139
Summit Materials, LLC | Ready-mix concrete
Revenue from External Customer [Line Items]
Total revenue	157,563	158,233
Summit Materials, LLC | Asphalt
Revenue from External Customer [Line Items]
Total revenue	17,138	28,375
Summit Materials, LLC | Paving and related services
Revenue from External Customer [Line Items]
Total revenue	30,610	43,215
Summit Materials, LLC | Other
Revenue from External Customer [Line Items]
Total revenue	$ 49,689	$ 42,494