Property, Plant and Equipment, net and Intangibles, net - Capital Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Property, Plant and Equipment [Line Items]
Depreciation, depletion and amortization expense	$ 177,643	$ 147,736	$ 118,321
Property, plant and equipment, net	1,615,424	1,446,452
Property, plant and equipment, accumulated depreciation, depletion and amortization	631,841	484,554
Capital lease obligations, current	19,276	11,766
2018	20,500
2019	7,600
2020	5,900
2021	1,400
2022	600
General and administrative expenses
Property, Plant and Equipment [Line Items]
Gain (loss) on disposition	7,500	6,800	23,500
Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Depreciation, depletion and amortization expense	177,643	147,736	$ 118,321
Property, plant and equipment, net	1,615,424	1,446,452
Property, plant and equipment, accumulated depreciation, depletion and amortization	631,841	484,554
Capital lease obligations, current	19,276	11,766
2018	20,500
2019	7,600
2020	5,900
2021	1,400
2022	600
Capital leases for equipment and building
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	51,200	49,800
Property, plant and equipment, accumulated depreciation, depletion and amortization	18,500	10,600
Capital leases for equipment and building | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	51,200	49,800
Property, plant and equipment, accumulated depreciation, depletion and amortization	$ 18,500	10,600
Capital leases for equipment and building | Summit Materials, LLC | Maximum
Property, Plant and Equipment [Line Items]
Equipment leases terms	5 years
Building lease original term	30 years
Accrued expenses | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Capital lease obligations, current	$ 19,300	11,800
Accrued expenses | Capital leases for equipment and building
Property, Plant and Equipment [Line Items]
Capital lease obligations, current	19,300	11,800
Noncurrent liabilities | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Capital lease obligations, noncurrent	16,400	27,500
Noncurrent liabilities | Capital leases for equipment and building
Property, Plant and Equipment [Line Items]
Capital lease obligations, noncurrent	$ 16,400	$ 27,500