Stock-Based Compensation (Tables)

12 Months Ended

Dec. 29, 2018

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of Information for the Equity Awards Granted

The following table summarizes information for the equity awards granted in 2018:

	Options				Restricted Stock Units				Performance Stock Units				Warrants
			Weighted				Weighted				Weighted				Weighted
			average grant-		Number of		average grant-		Number of		average grant-				average grant-
	Number of		date fair value		restricted		date fair value		performance		date fair value		Number of		date fair value
	options		per unit		stock units		per unit		stock units		per unit		warrants		per unit
Beginning balance—December 30, 2017	4,153,613		$	9.13	508,586		$	20.14	211,455		$	23.69	102,778		$	18.00
Granted	—		—		689,386		28.68		102,842		40.83		—		—
Forfeited	(22,566	)	10.91		(21,551	)	28.11		(19,045	)	26.26		—		—
Exercised	(863,898	)	8.88		—		—		—		—		(2,741	)	18.00
Vested	—		—		(252,113	)	21.95		—		—		—		—
Balance—December 29, 2018	3,267,149		$	9.09	924,308		$	24.57	295,252		$	29.12	100,037		$	18.00

Weighted Average Assumptions Used to Estimate the Fair Value of Grants

The following table presents the weighted average assumptions used to estimate the fair value of grants in 2018, 2017 and 2016:

	Options		Performance Stock Units
	2017	2016	2018	2017	2016
Risk-free interest rate	2.06% - 2.31%	1.75% - 1.97%	2.38%	1.45%	0.88%
Dividend yield	N/A	N/A	N/A	N/A	N/A
Volatility	47%	48%	38%	39%	37%
Expected term	7 years	10 years	3 years	3 years	3 years

Summit Materials, LLC

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of Information for the Equity Awards Granted

The following table summarizes information for the equity awards granted in 2018:

	Options				Restricted Stock Units				Performance Stock Units				Warrants
			Weighted				Weighted				Weighted				Weighted
			average grant-		Number of		average grant-		Number of		average grant-				average grant-
	Number of		date fair value		restricted		date fair value		performance		date fair value		Number of		date fair value
	options		per unit		stock units		per unit		stock units		per unit		warrants		per unit
Beginning balance—December 30, 2017	4,153,613		$	9.13	508,586		$	20.14	211,455		$	23.69	102,778		$	18.00
Granted	—		—		689,386		28.68		102,842		40.83		—		—
Forfeited	(22,566	)	10.91		(21,551	)	28.11		(19,045	)	26.26		—		—
Exercised	(863,898	)	8.88		—		—		—		—		(2,741	)	18.00
Vested	—		—		(252,113	)	21.95		—		—		—		—
Balance—December 29, 2018	3,267,149		$	9.09	924,308		$	24.57	295,252		$	29.12	100,037		$	18.00

Weighted Average Assumptions Used to Estimate the Fair Value of Grants

The following table presents the weighted average assumptions used to estimate the fair value of grants in 2018, 2017 and 2016:

	Options			Performance Stock Units
		2017	2016	2018	2017	2016
Risk-free interest rate		2.06% - 2.31%	1.75% - 1.97%	2.38%	1.45%	0.88%
Dividend yield		N/A	N/A	N/A	N/A	N/A
Volatility		47%	48%	38%	39%	37%
Expected term		7 years	10 years	3 years	3 years	3 years