Leasing Arrangements - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Leases [Abstract]
Rent expense, including short-term rentals	$ 21.7	$ 18.6	$ 12.1
Royalty expense recorded in cost of revenue	18.7	15.6	12.6
Summit Materials, LLC
Leases [Abstract]
Rent expense, including short-term rentals	21.7	18.6	12.1
Royalty expense recorded in cost of revenue	$ 18.7	$ 15.6	$ 12.6