Unaudited Consolidated Statements of Changes in Stockholders’ Equity - Summit Materials Inc - USD ($) $ in Thousands	Total	Common Class A	Common Class B	Accumulated Earnings	Accumulated Other Comprehensive Income	Common Stock Common Class A	Common Stock Common Class B	Additional Paid-in Capital	Noncontrolling Interest
Beginning balance at Dec. 31, 2022	$ 2,011,990			$ 590,895	$ 3,084	$ 1,185	$ 0	$ 1,404,122	$ 12,704
Beginning balance (in shares) at Dec. 31, 2022		118,408,655				118,408,655	99
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(31,212)			(30,804)					(408)
LP Unit exchanges (in shares)		2,000				2,000
LP Unit exchanges	0							21	(21)
Other comprehensive income (loss), net of tax	164				161				3
Stock option exercises (in shares)		902				902
Stock option exercises	15							15
Share-based compensation	4,708							4,708
Shares redeemed to settle taxes and other (in shares)		407,114				407,114
Shares redeemed to settle taxes and other	(5,719)					$ 4		(5,680)	(43)
Ending balance at Apr. 01, 2023	1,979,946			560,091	3,245	$ 1,189	$ 0	1,403,186	12,235
Ending balance (in shares) at Apr. 01, 2023		118,818,671				118,818,671	99
Beginning balance at Dec. 30, 2023	2,316,580			876,751	7,275	$ 1,196	$ 0	1,421,813	9,545
Beginning balance (in shares) at Dec. 30, 2023		119,529,380	99			119,529,380	99
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(67,270)			(66,866)					(404)
LP Unit exchanges (in shares)		763,243				763,243
LP Unit exchanges	0					$ 8		9,534	(9,542)
Other comprehensive income (loss), net of tax	(3,585)				(3,585)				0
Stock option exercises (in shares)		29,216				29,216
Stock option exercises	$ 593							593
Class B share cancellation (in shares)	(99)
Share-based compensation	$ 6,720							6,720
Issuance of Class A common stock (in shares)		54,720,000
Issuance of Class A common stock	1,973,750	$ 547						1,973,203
Shares redeemed to settle taxes and other (in shares)		412,411				412,411
Shares redeemed to settle taxes and other	(8,151)					$ 4		(8,556)	401
Ending balance at Mar. 30, 2024	$ 4,218,637			$ 809,885	$ 3,690	$ 1,755	$ 0	$ 3,403,307	$ 0
Ending balance (in shares) at Mar. 30, 2024		175,454,250	0			175,454,250	0