Segment Information - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Cash payments:
Income Taxes Paid	$ 1,711	$ 2,645	$ 1,685
Summit Materials, LLC
Cash payments:
Income Taxes Paid	$ 1,711	$ 2,645	$ 1,685