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 (loss)	Common Stock Common Class A	Common Stock Common Class B	Additional Paid-in Capital	Noncontrolling Interest In Summit Holdings
Beginning balance at Jan. 01, 2022	$ 1,823,212			$ 478,956	$ 7,083	$ 1,188	$ 0	$ 1,326,340	$ 9,645
Beginning balance (in shares) at Jan. 01, 2022		120,684,322				118,705,108	99
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(34,800)			(34,292)					(508)
Other comprehensive income, net of tax	1,325				1,306				19
Stock option exercises (in shares)		1,589				1,589
Stock option exercises	27					$ 0		27
Share-based compensation	5,422							5,422
Repurchases of common stock	(47,509)			(47,494)		$ (15)		(121)	121
Repurchases of common stock, (in shares)						(1,506,878)
Shares redeemed to settle taxes and other (in shares)		842,029				842,029
Shares redeemed to settle taxes and other	(1,180)					$ 8		(1,120)	(68)
Ending balance at Apr. 02, 2022	1,746,497			397,170	8,389	$ 1,181	$ 0	1,330,548	9,209
Ending balance (in shares) at Apr. 02, 2022		120,021,062				118,041,848	99
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	99			118,408,655	99
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(31,212)			(30,804)					(408)
LP Unit exchanges (in shares)		2,000				2,000
LP Unit exchanges	0							21	(21)
Other comprehensive income, 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
Repurchases of common stock		$ (149,000)
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	99			118,818,671	99