Acquisitions - Contractual Obligations (Details) $ in Thousands	12 Months Ended
	Dec. 30, 2017 USD ($)
Minimum
Remaining payments on contractual obligations
Term of payment for deferred consideration	5 years
Maximum
Remaining payments on contractual obligations
Term of payment for deferred consideration	20 years
Noncompete and Deferred Consideration Agreements [Member]
Remaining payments on contractual obligations
2018	$ 13,760
2019	9,187
2020	7,973
2021	7,958
2022	1,803
Thereafter	6,763
Total scheduled payments	47,444
Present value adjustments	(10,117)
Total noncompete obligations and deferred consideration	$ 37,327
Summit Materials, LLC
Remaining payments on contractual obligations
Average term of noncompete agreements	5 years
Summit Materials, LLC | Minimum
Remaining payments on contractual obligations
Term of payment for deferred consideration	5 years
Summit Materials, LLC | Maximum
Remaining payments on contractual obligations
Term of payment for deferred consideration	20 years
Summit Materials, LLC | Noncompete and Deferred Consideration Agreements [Member]
Remaining payments on contractual obligations
2018	$ 11,260
2019	6,687
2020	5,473
2021	5,458
2022	1,803
Thereafter	6,763
Total scheduled payments	37,444
Present value adjustments	(8,513)
Total noncompete obligations and deferred consideration	$ 28,931