LEASES - Operating and Finance Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 02, 2022	Apr. 03, 2021	Jan. 01, 2022
Lease, Cost [Abstract]
Operating lease cost	$ 2,512	$ 1,727
Variable lease cost	113	72
Short-term lease cost	8,248	7,301
Financing lease cost:
Amortization of right-of-use assets	1,986	3,050
Interest on lease liabilities	369	657
Total lease cost	13,228	12,807
Operating leases:
Operating lease right-of-use assets	28,766		$ 30,150
Current operating lease liabilities	5,934		6,497
Noncurrent operating lease liabilities	28,017		28,880
Total operating lease liabilities	33,951		35,377
Finance leases:
Property and equipment, gross	63,040		68,982
Less accumulated depreciation	$ (31,459)		$ (31,404)
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, plant and equipment, net		Property, plant and equipment, net
Property and equipment, net	$ 31,581		$ 37,578
Current finance lease liabilities	14,234		17,624
Long-term finance lease liabilities	10,557		14,982
Total finance lease liabilities	$ 24,791		$ 32,606
Weighted average remaining lease term (years):
Operating leases	9 years 8 months 12 days		9 years 8 months 12 days
Finance lease	2 years 6 months		2 years 3 months 18 days
Weighted average discount rate:
Operating leases	4.40%		4.40%
Finance leases	5.10%		5.20%
Operating Leases
2022 (nine months)	$ 5,352
2023	6,197
2024	4,883
2025	3,612
2026	2,952
2027	2,456
Thereafter	17,307
Total lease payments	42,759
Less imputed interest	(8,808)
Present value of lease payments	33,951		$ 35,377
Finance Leases
2022 (nine months)	11,198
2023	7,510
2024	2,936
2025	2,415
2026	990
2027	760
Thereafter	1,083
Total lease payments	26,892
Less imputed interest	(2,101)
Present value of lease payments	24,791		32,606
Summit Materials, LLC
Lease, Cost [Abstract]
Operating lease cost	2,512	1,727
Variable lease cost	113	72
Short-term lease cost	8,248	7,301
Financing lease cost:
Amortization of right-of-use assets	1,986	3,050
Interest on lease liabilities	369	657
Total lease cost	13,228	$ 12,807
Operating leases:
Operating lease right-of-use assets	28,766		30,150
Current operating lease liabilities	5,934		6,497
Noncurrent operating lease liabilities	28,017		28,880
Total operating lease liabilities	33,951		35,377
Finance leases:
Property and equipment, gross	63,040		68,982
Less accumulated depreciation	$ (31,459)		$ (31,404)
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, plant and equipment, net		Property, plant and equipment, net
Property and equipment, net	$ 31,581		$ 37,578
Current finance lease liabilities	14,234		17,624
Long-term finance lease liabilities	10,557		14,982
Total finance lease liabilities	$ 24,791		$ 32,606
Weighted average remaining lease term (years):
Operating leases	9 years 8 months 12 days		9 years 8 months 12 days
Finance lease	2 years 6 months		2 years 3 months 18 days
Weighted average discount rate:
Operating leases	4.40%		4.40%
Finance leases	5.10%		5.20%
Operating Leases
2022 (nine months)	$ 5,352
2023	6,197
2024	4,883
2025	3,612
2026	2,952
2027	2,456
Thereafter	17,307
Total lease payments	42,759
Less imputed interest	(8,808)
Present value of lease payments	33,951		$ 35,377
Finance Leases
2022 (nine months)	11,198
2023	7,510
2024	2,936
2025	2,415
2026	990
2027	760
Thereafter	1,083
Total lease payments	26,892
Less imputed interest	(2,101)
Present value of lease payments	$ 24,791		$ 32,606