Stock-Based Compensation (Tables)

12 Months Ended

Dec. 30, 2017

Summary of Information for the Equity Awards Granted

	Options			Restricted Stock Units			Performance Stock Units			Warrants
		Weighted			Weighted			Weighted			Weighted
		average grant-		Number of	average grant-		Number of	average grant-		Number of	average grant-
	Number of	date fair value		restricted	date fair value		performance	date fair value		performance	date fair value
	options	per unit		stock units	per unit		stock units	per unit		stock units	per unit
Beginning balance—December 31, 2016	4,990,443	$	8.95	352,602	$	17.77	130,691	$	18.71	160,333	$	18.00
Granted	377,630		12.13	307,905		24.01	85,530		31.58	—		—
Forfeited	(11,339)		10.91	(6,109)		20.37	(4,766)		18.71	—		—
Exercised	(1,203,121)		8.90	—		—	—		—	(57,555)		18.00
Vested	—		—	(145,812)		17.68	—		—	—		—
Balance—December 30, 2017	4,153,613	$	9.13	508,586	$	20.14	211,455	$	23.69	102,778	$	18.00

Weighted Average Assumptions Used to Estimate the Fair Value of Grants

	Options			Performance Stock Units
	2017	2016	2015	2017	2016
Risk-free interest rate	2.06% - 2.31%	1.75% - 1.97%	1.68% - 1.92%	1.45%	0.88%
Dividend yield	None	None	None	None	None
Volatility	47%	48%	50%	39%	37%
Expected term	7 Years	10 Years	7 - 10 years	3 Years	3 Years

Summit Materials, LLC

Summary of Information for the Equity Awards Granted

	Options			Restricted Stock Units			Performance Stock Units			Warrants
		Weighted			Weighted			Weighted			Weighted
		average grant-		Number of	average grant-		Number of	average grant-		Number of	average grant-
	Number of	date fair value		restricted	date fair value		performance	date fair value		performance	date fair value
	options	per unit		stock units	per unit		stock units	per unit		stock units	per unit
Beginning balance—December 31, 2016	4,990,443	$	8.95	352,602	$	17.77	130,691	$	18.71	160,333	$	18.00
Granted	377,630		12.13	307,905		24.01	85,530		31.58	—		—
Forfeited	(11,339)		10.91	(6,109)		20.37	(4,766)		18.71	—		—
Exercised	(1,203,121)		8.90	—		—	—		—	(57,555)		18.00
Vested	—		—	(145,812)		17.68	—		—	—		—
Balance—December 30, 2017	4,153,613	$	9.13	508,586	$	20.14	211,455	$	23.69	102,778	$	18.00

Weighted Average Assumptions Used to Estimate the Fair Value of Grants

	Options			Performance Stock Units
	2017	2016	2015	2017	2016
Risk-free interest rate	2.06% - 2.31%	1.75% - 1.97%	1.68% - 1.92%	1.45%	0.88%
Dividend yield	None	None	None	None	None
Volatility	47%	48%	50%	39%	37%
Expected term	7 Years	10 Years	7 - 10 years	3 Years	3 Years