STOCKHOLDERS' EQUITY/MEMBERS' INTEREST - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 02, 2022	Apr. 03, 2021
Changes in each component of accumulated other comprehensive loss
Beginning balance	$ 1,823,212	$ 1,616,268
Foreign currency translation adjustment, net of tax	1,306	1,635
Ending balance	1,746,497	1,614,560
Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Foreign currency translation adjustment, net of tax	1,744	2,126
Change in retirement plans
Changes in each component of accumulated other comprehensive loss
Beginning balance	1,508	533
Ending balance	1,508	533
Change in retirement plans | Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Beginning balance	(7,243)	(8,546)
Ending balance	(7,243)	(8,546)
Foreign currency translation adjustments
Changes in each component of accumulated other comprehensive loss
Beginning balance	5,575	4,670
Foreign currency translation adjustment, net of tax	1,306	1,635
Ending balance	6,881	6,305
Foreign currency translation adjustments | Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Beginning balance	(8,783)	(10,037)
Foreign currency translation adjustment, net of tax	1,744	2,126
Ending balance	(7,039)	(7,911)
Cash flow hedge adjustments | Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Beginning balance	0	0
Ending balance	0	0
Accumulated other comprehensive income (loss)
Changes in each component of accumulated other comprehensive loss
Beginning balance	7,083	5,203
Ending balance	8,389	6,838
Accumulated other comprehensive income (loss) | Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Beginning balance	(16,026)	(18,583)
Ending balance	$ (14,282)	$ (16,457)