Property, Plant and Equipment, net and Intangibles, net - Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 23,531	$ 25,843
Accumulated Amortization	(6,698)	(7,854)
Net Carrying Amount	16,833	17,989
Amortization expense	1,300	2,600	$ 2,200
Estimated amortization expense
2018	1,281
2019	1,268
2020	1,185
2021	1,142
2022	1,113
Thereafter	10,844
Total	16,833	17,989
Summit Materials, LLC
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	23,531	25,843
Accumulated Amortization	(6,698)	(7,854)
Net Carrying Amount	16,833	17,989
Amortization expense	1,300	2,600	$ 2,200
Estimated amortization expense
2018	1,281
2019	1,268
2020	1,185
2021	1,142
2022	1,113
Thereafter	10,844
Total	16,833	17,989
Leases
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	15,888	15,888
Accumulated Amortization	(4,178)	(3,382)
Net Carrying Amount	11,710	12,506
Leases | Summit Materials, LLC
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	15,888	15,888
Accumulated Amortization	(4,178)	(3,382)
Net Carrying Amount	11,710	12,506
Reserve Rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6,234	8,706
Accumulated Amortization	(1,625)	(3,710)
Net Carrying Amount	4,609	4,996
Reserve Rights | Summit Materials, LLC
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6,234	8,706
Accumulated Amortization	(1,625)	(3,710)
Net Carrying Amount	4,609	4,996
Trade Names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,000	1,000
Accumulated Amortization	(758)	(658)
Net Carrying Amount	242	342
Trade Names | Summit Materials, LLC
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,000	1,000
Accumulated Amortization	(758)	(658)
Net Carrying Amount	242	342
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	409	249
Accumulated Amortization	(137)	(104)
Net Carrying Amount	272	145
Other | Summit Materials, LLC
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	409	249
Accumulated Amortization	(137)	(104)
Net Carrying Amount	$ 272	$ 145