GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - Schedule of Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Thousands	Jul. 01, 2023	Apr. 01, 2023	Dec. 31, 2022	Jul. 02, 2022	Apr. 02, 2022	Jan. 01, 2022
Current assets:
Cash and cash equivalents	$ 230,010		$ 520,451
Accounts receivable, net	370,504		256,669
Cost and estimated earnings in excess of billings	35,315		6,510
Inventories	246,275		212,491
Total current assets	906,302		1,018,376
Property, plant and equipment, net	1,979,986		1,813,702
Goodwill	1,228,468		1,132,546
Intangible assets, net	69,714		71,384
Operating lease right-of-use assets	36,013		37,889
Total assets	4,395,487		4,255,692
Current liabilities:
Current portion of debt	5,096		5,096
Current portion of acquisition-related liabilities	7,243		13,718
Accounts payable	171,221		104,031
Current operating lease liabilities	7,707		7,296
Billings in excess of costs and estimated earnings	7,054		5,739
Total current liabilities	346,981		255,847
Long-term debt	1,487,289		1,488,569
Acquisition-related liabilities	23,503		29,051
Noncurrent operating lease liabilities	33,563		35,737
Total liabilities	2,321,523		2,243,702
Total liabilities and members' interest	4,395,487		4,255,692
Summit Materials, LLC
Current assets:
Cash and cash equivalents	230,010		520,451
Accounts receivable, net	370,504		256,669
Intercompany receivables	0		0
Cost and estimated earnings in excess of billings	35,315		6,510
Inventories	246,275		212,491
Other current assets	24,198		22,255
Total current assets	906,302		1,018,376
Property, plant and equipment, net	1,979,986		1,813,702
Goodwill	1,229,468		1,133,546
Intangible assets, net	69,714		71,384
Operating lease right-of-use assets	36,013		37,889
Other assets	48,187		44,809
Total assets	4,269,670		4,119,706
Current liabilities:
Current portion of debt	5,096		5,096
Current portion of acquisition-related liabilities	7,243		13,718
Accounts payable	171,076		104,430
Accrued expenses	144,745		120,708
Current operating lease liabilities	7,707		7,296
Intercompany payables	0		0
Billings in excess of costs and estimated earnings	7,054		5,739
Total current liabilities	342,921		256,987
Long-term debt	1,487,289		1,488,569
Acquisition-related liabilities	23,503		29,051
Noncurrent operating lease liabilities	33,563		35,737
Other noncurrent liabilities	167,090		166,212
Total liabilities	2,054,366		1,976,556
Total member's interest	2,215,304	$ 2,105,146	2,143,150	$ 2,039,348	$ 1,797,061	$ 1,884,944
Total liabilities and members' interest	4,269,670		4,119,706
Summit Materials, LLC | Eliminations
Current assets:
Cash and cash equivalents	(5,375)		(7,018)
Accounts receivable, net	(91)		(25)
Intercompany receivables	(2,296,652)		(2,267,134)
Cost and estimated earnings in excess of billings	0		0
Inventories	0		0
Other current assets	0		0
Total current assets	(2,302,118)		(2,274,177)
Property, plant and equipment, net	0		0
Goodwill	0		0
Intangible assets, net	0		0
Operating lease right-of-use assets	0		0
Other assets	(5,185,889)		(4,760,543)
Total assets	(7,488,007)		(7,034,720)
Current liabilities:
Current portion of debt	0		0
Current portion of acquisition-related liabilities	0		0
Accounts payable	(91)		(25)
Accrued expenses	(5,375)		(7,018)
Current operating lease liabilities	0		0
Intercompany payables	(2,296,652)		(2,267,134)
Billings in excess of costs and estimated earnings	0		0
Total current liabilities	(2,302,118)		(2,274,177)
Long-term debt	0		0
Acquisition-related liabilities	0		0
Noncurrent operating lease liabilities	0		0
Other noncurrent liabilities	(164,421)		(164,421)
Total liabilities	(2,466,539)		(2,438,598)
Total member's interest	(5,021,468)		(4,596,122)
Total liabilities and members' interest	(7,488,007)		(7,034,720)
Summit Materials, LLC | Issuers | Reportable Legal Entities
Current assets:
Cash and cash equivalents	197,481		498,307
Accounts receivable, net	603		1,528
Intercompany receivables	311,267		329,744
Cost and estimated earnings in excess of billings	0		0
Inventories	0		0
Other current assets	11,596		4,755
Total current assets	520,947		834,334
Property, plant and equipment, net	27,660		21,306
Goodwill	0		0
Intangible assets, net	0		0
Operating lease right-of-use assets	4,225		4,665
Other assets	5,016,546		4,599,488
Total assets	5,569,378		5,459,793
Current liabilities:
Current portion of debt	5,096		5,096
Current portion of acquisition-related liabilities	0		0
Accounts payable	5,622		3,553
Accrued expenses	64,653		54,417
Current operating lease liabilities	946		921
Intercompany payables	1,776,656		1,750,352
Billings in excess of costs and estimated earnings	0		0
Total current liabilities	1,852,973		1,814,339
Long-term debt	1,487,289		1,488,569
Acquisition-related liabilities	0		0
Noncurrent operating lease liabilities	8,315		8,726
Other noncurrent liabilities	5,497		5,009
Total liabilities	3,354,074		3,316,643
Total member's interest	2,215,304		2,143,150
Total liabilities and members' interest	5,569,378		5,459,793
Summit Materials, LLC | Guarantors  | Reportable Legal Entities
Current assets:
Cash and cash equivalents	5,698		2,864
Accounts receivable, net	341,501		233,039
Intercompany receivables	1,985,385		1,937,390
Cost and estimated earnings in excess of billings	33,533		5,861
Inventories	239,848		206,418
Other current assets	11,143		16,341
Total current assets	2,617,108		2,401,913
Property, plant and equipment, net	1,871,238		1,710,972
Goodwill	1,171,500		1,076,935
Intangible assets, net	65,279		66,972
Operating lease right-of-use assets	27,149		28,310
Other assets	216,720		204,644
Total assets	5,968,994		5,489,746
Current liabilities:
Current portion of debt	0		0
Current portion of acquisition-related liabilities	7,243		13,718
Accounts payable	153,815		93,096
Accrued expenses	82,359		70,433
Current operating lease liabilities	6,099		5,637
Intercompany payables	516,160		513,494
Billings in excess of costs and estimated earnings	6,313		4,956
Total current liabilities	771,989		701,334
Long-term debt	0		0
Acquisition-related liabilities	23,503		29,051
Noncurrent operating lease liabilities	21,355		22,871
Other noncurrent liabilities	208,578		208,185
Total liabilities	1,025,425		961,441
Total member's interest	4,943,569		4,528,305
Total liabilities and members' interest	5,968,994		5,489,746
Summit Materials, LLC | Non-Guarantors | Reportable Legal Entities
Current assets:
Cash and cash equivalents	32,206		26,298
Accounts receivable, net	28,491		22,127
Intercompany receivables	0		0
Cost and estimated earnings in excess of billings	1,782		649
Inventories	6,427		6,073
Other current assets	1,459		1,159
Total current assets	70,365		56,306
Property, plant and equipment, net	81,088		81,424
Goodwill	57,968		56,611
Intangible assets, net	4,435		4,412
Operating lease right-of-use assets	4,639		4,914
Other assets	810		1,220
Total assets	219,305		204,887
Current liabilities:
Current portion of debt	0		0
Current portion of acquisition-related liabilities	0		0
Accounts payable	11,730		7,806
Accrued expenses	3,108		2,876
Current operating lease liabilities	662		738
Intercompany payables	3,836		3,288
Billings in excess of costs and estimated earnings	741		783
Total current liabilities	20,077		15,491
Long-term debt	0		0
Acquisition-related liabilities	0		0
Noncurrent operating lease liabilities	3,893		4,140
Other noncurrent liabilities	117,436		117,439
Total liabilities	141,406		137,070
Total member's interest	77,899		67,817
Total liabilities and members' interest	$ 219,305		$ 204,887