STOCKHOLDERS' EQUITY/MEMBERS' INTEREST - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jul. 01, 2023	Jul. 02, 2022
Changes in each component of accumulated other comprehensive loss
Beginning balance	$ 2,011,990	$ 1,823,212
Foreign currency translation adjustment, net of tax	3,242	(2,890)
Ending balance	2,073,964	1,940,802
Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Beginning balance	2,143,150	1,884,944
Foreign currency translation adjustment, net of tax	4,105	(3,866)
Ending balance	2,215,304	2,039,348
Change in retirement plans
Changes in each component of accumulated other comprehensive loss
Beginning balance	6,356	1,508
Ending balance	6,356	1,508
Change in retirement plans | Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Beginning balance	(762)	(7,243)
Ending balance	(762)	(7,243)
Foreign currency translation adjustments
Changes in each component of accumulated other comprehensive loss
Beginning balance	(3,272)	5,575
Foreign currency translation adjustment, net of tax	3,242	(2,890)
Ending balance	(30)	2,685
Foreign currency translation adjustments | Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Beginning balance	(20,614)	(8,783)
Foreign currency translation adjustment, net of tax	4,105	(3,866)
Ending balance	(16,509)	(12,649)
Accumulated Other Comprehensive Income
Changes in each component of accumulated other comprehensive loss
Beginning balance	3,084	7,083
Ending balance	6,326	4,193
Accumulated Other Comprehensive Income | Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Beginning balance	(21,376)	(16,026)
Ending balance	$ (17,271)	$ (19,892)