Accrued Expenses - Components of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 29, 2018	Dec. 30, 2017
Schedule Of Accrued Expenses [Line Items]
Interest	$ 26,223	$ 24,095
Payroll and benefits	15,952	33,915
Capital lease obligations	15,557	19,276
Insurance	13,625	11,455
Non-income taxes	7,442	7,236
Professional fees	1,408	1,717
Other	20,284	18,935
Total	100,491	116,629
Summit Materials, LLC
Schedule Of Accrued Expenses [Line Items]
Interest	26,223	24,095
Payroll and benefits	15,952	33,915
Capital lease obligations	15,557	19,276
Insurance	13,625	11,455
Non-income taxes	7,674	7,467
Professional fees	1,408	1,717
Other	19,590	18,349
Total	$ 100,029	$ 116,274