SEGMENT INFORMATION - Financial Data (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2023 USD ($)	Jul. 02, 2022 USD ($)	Jul. 01, 2023 USD ($) segment	Jul. 02, 2022 USD ($)	Dec. 31, 2022 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment			3
Number of reportable segments | segment			3
Total revenue	$ 729,150	$ 686,554	$ 1,164,538	$ 1,107,501
Income from operations before taxes	107,209	246,713	69,531	207,170
Interest expense	27,902	20,599	55,322	40,748
Depreciation, depletion and amortization	54,042	46,455	104,230	96,934
Accretion	745	702	1,451	1,416
Loss on debt financings	0	0	493	0
Tax receivable agreement expense	0	954	0	954
Gain on sale of businesses	0	(156,053)	0	(170,258)
Non-cash compensation	5,216	4,734	9,924	10,156
Other	(3,369)	(70)	(8,005)	177
Total Adjusted EBITDA	191,745	164,034	232,946	187,297
Total purchases of property, plant and equipment			126,893	129,580
Total depreciation, depletion, amortization and accretion	54,787	47,157	105,681	98,350
Total assets	4,395,487		4,395,487		$ 4,255,692
Operating segment
Segment Reporting Information [Line Items]
Total purchases of property, plant and equipment			120,542	123,922
Total depreciation, depletion, amortization and accretion	53,753	46,387	103,659	96,831
Total assets	4,026,126		4,026,126		3,590,603
Corporate and other
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	(13,261)	(10,545)	(23,600)	(22,291)
Total purchases of property, plant and equipment			6,351	5,658
Total depreciation, depletion, amortization and accretion	1,034	770	2,022	1,519
Total assets	369,361		369,361		665,089
West
Segment Reporting Information [Line Items]
Total revenue	430,738	383,750	681,620	635,982
West | Operating segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	104,517	84,644	137,195	117,336
Total purchases of property, plant and equipment			70,687	58,137
Total depreciation, depletion, amortization and accretion	28,144	22,012	54,517	46,587
Total assets	1,919,824		1,919,824		1,565,776
East
Segment Reporting Information [Line Items]
Total revenue	186,537	209,153	316,926	331,643
East | Operating segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	47,617	46,694	66,469	54,830
Total purchases of property, plant and equipment			30,378	45,910
Total depreciation, depletion, amortization and accretion	15,718	14,915	31,253	33,210
Total assets	1,181,536		1,181,536		1,151,223
Cement
Segment Reporting Information [Line Items]
Total revenue	111,875	93,651	165,992	139,876
Cement | Operating segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	52,872	43,241	52,882	37,422
Total purchases of property, plant and equipment			19,477	19,875
Total depreciation, depletion, amortization and accretion	9,891	9,460	17,889	17,034
Total assets	924,766		$ 924,766		873,604
Summit Materials, LLC
Segment Reporting Information [Line Items]
Number of operating segments | segment			3
Number of reportable segments | segment			3
Total revenue	729,150	686,554	$ 1,164,538	1,107,501
Income from operations before taxes	107,209	247,667	69,531	208,124
Interest expense	27,902	20,599	55,322	40,748
Depreciation, depletion and amortization	54,042	46,455	104,230	96,934
Accretion	745	702	1,451	1,416
Loss on debt financings	0	0	493	0
Gain on sale of businesses	0	(156,053)	0	(170,258)
Non-cash compensation	5,216	4,734	9,924	10,156
Other	(3,369)	(70)	(8,005)	177
Total Adjusted EBITDA	191,745	164,034	232,946	187,297
Total purchases of property, plant and equipment			126,893	129,580
Total depreciation, depletion, amortization and accretion	54,787	47,157	105,681	98,350
Total assets	4,269,670		4,269,670		4,119,706
Summit Materials, LLC | Operating segment
Segment Reporting Information [Line Items]
Total purchases of property, plant and equipment			120,542	123,922
Total depreciation, depletion, amortization and accretion	53,753	46,387	103,659	96,831
Total assets	4,026,126		4,026,126		3,590,603
Summit Materials, LLC | Corporate and other
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	(13,261)	(10,545)	(23,600)	(22,291)
Total purchases of property, plant and equipment			6,351	5,658
Total depreciation, depletion, amortization and accretion	1,034	770	2,022	1,519
Total assets	243,544		243,544		529,103
Summit Materials, LLC | West
Segment Reporting Information [Line Items]
Total revenue	430,738	383,750	681,620	635,982
Summit Materials, LLC | West | Operating segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	104,517	84,644	137,195	117,336
Total purchases of property, plant and equipment			70,687	58,137
Total depreciation, depletion, amortization and accretion	28,144	22,012	54,517	46,587
Total assets	1,919,824		1,919,824		1,565,776
Summit Materials, LLC | East
Segment Reporting Information [Line Items]
Total revenue	186,537	209,153	316,926	331,643
Summit Materials, LLC | East | Operating segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	47,617	46,694	66,469	54,830
Total purchases of property, plant and equipment			30,378	45,910
Total depreciation, depletion, amortization and accretion	15,718	14,915	31,253	33,210
Total assets	1,181,536		1,181,536		1,151,223
Summit Materials, LLC | Cement
Segment Reporting Information [Line Items]
Total revenue	111,875	93,651	165,992	139,876
Summit Materials, LLC | Cement | Operating segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	52,872	43,241	52,882	37,422
Total purchases of property, plant and equipment			19,477	19,875
Total depreciation, depletion, amortization and accretion	9,891	$ 9,460	17,889	$ 17,034
Total assets	$ 924,766		$ 924,766		$ 873,604