Summary of Organization and Significant Accounting Policies - Business and Credit Concentration (Details)	12 Months Ended
	Dec. 30, 2017 state item	Dec. 31, 2016 item	Jan. 02, 2016 item	Dec. 27, 2014 item
Business and Credit Concentrations
Number of states in which the entity operates	23
Percentage of benefits to be paid on tax receivable agreement	85.00%
Sales | Customer Concentration Risk
Business and Credit Concentrations
Number of customers accounted for more than 10% of total revenue	0	0	0
Sales | Customer Concentration Risk | Maximum
Business and Credit Concentrations
Customer accounted revenue (as a percent)	10.00%	10.00%	10.00%
Summit Materials, LLC
Business and Credit Concentrations
Number of states in which the entity operates | state	23
Summit Materials, LLC | Sales | Maximum
Business and Credit Concentrations
Customer accounted revenue (as a percent)		10.00%	10.00%	10.00%
Summit Materials, LLC | Sales | Customer Concentration Risk
Business and Credit Concentrations
Number of customers accounted for more than 10% of total revenue		0	0	0
Tax Receivable Agreement
Business and Credit Concentrations
Percentage of benefits to be paid on tax receivable agreement	85.00%