Supplemental Cash Flow Information - Schedule of Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Cash payments:
Interest	$ 96,320	$ 82,540	$ 89,102
Income taxes	1,711	2,645	1,685
Non cash financing activities:
Purchase of noncontrolling interest	(716)		(29,102)
Stock Dividend	(45,023)	(26,939)	(16,847)
Exchange of LP units to Common A Stock	41,126	953,752
Summit Materials, LLC
Cash payments:
Interest	96,320	82,540	89,102
Income taxes	1,711	$ 2,645	1,685
Non cash financing activities:
Purchase of noncontrolling interest	$ (716)		$ (64,102)