v3.22.4
Stock-Based Compensation - Narrative (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2022
Jan. 01, 2022
Jan. 02, 2021
May 31, 2021
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Purchase price percentage       85.00%  
Dividend yield 0.00% 0.00% 0.00%    
Share-based compensation expense $ 18.3 $ 19.7 $ 28.9    
Unrecognized compensation cost $ 19.5        
Weighted average contractual term, unrecognized compensation cost 1 year 8 months 12 days        
2015 Omnibus Equity Incentive Plan | Common Class A          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of shares authorized (in shares)       17,500,000  
Shares available for grant (in shares) 7,200,000        
Employee Stock Purchase Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of shares authorized (in shares) 5,500,000     5,500,000  
Offering period 6 months        
Common stock reserved for future issuance (in shares) 5,400,000        
Restricted Stock Units          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Awards granted during the period (in shares) 557,253        
Intrinsic value, units outstanding $ 31.2        
Weighted average remaining contractual term 9 months 18 days        
Restricted Stock Units | 2015 Omnibus Equity Incentive Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Award vesting period 1 year        
Awards granted during the period (in shares) 30,520 34,672 42,736    
Time-vesting stock options          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Options, granted (in shares) 0 0 0    
Intrinsic value, options outstanding $ 2.4        
Weighted average remaining contractual term 3 years        
Weighted average strike price, outstanding (in dollars per share) $ 19.75        
Performance Stock Units          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Award vesting period 3 years        
Awards granted during the period (in shares) 316,705        
Intrinsic value, units outstanding $ 11.7        
Weighted average remaining contractual term 1 year 2 months 12 days        
Exercisable stock options outstanding (in shares) 300,000        
Summit Materials, LLC          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Purchase price percentage       85.00%  
Dividend yield 0.00% 0.00% 0.00%    
Share-based compensation expense $ 18.3 $ 19.7 $ 28.9    
Unrecognized compensation cost $ 19.5        
Weighted average contractual term, unrecognized compensation cost 1 year 8 months 12 days        
Summit Materials, LLC | 2015 Omnibus Equity Incentive Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of shares authorized (in shares)         17,500,000
Summit Materials, LLC | 2015 Omnibus Equity Incentive Plan | Common Class A          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares available for grant (in shares) 7,200,000        
Summit Materials, LLC | Employee Stock Purchase Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of shares authorized (in shares) 5,500,000     5,500,000  
Offering period 6 months        
Common stock reserved for future issuance (in shares) 5,400,000        
Summit Materials, LLC | Restricted Stock Units          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Awards granted during the period (in shares) 557,253        
Intrinsic value, units outstanding $ 31.2        
Weighted average remaining contractual term 9 months 18 days        
Summit Materials, LLC | Restricted Stock Units | 2015 Omnibus Equity Incentive Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Award vesting period 1 year        
Awards granted during the period (in shares) 30,520 34,672 42,736    
Summit Materials, LLC | Time-vesting stock options          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Options, granted (in shares) 0 0 0    
Intrinsic value, options outstanding $ 2.4        
Weighted average remaining contractual term 3 years        
Weighted average strike price, outstanding (in dollars per share) $ 19.75        
Summit Materials, LLC | Performance Stock Units          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Award vesting period 3 years        
Awards granted during the period (in shares) 316,705        
Intrinsic value, units outstanding $ 11.7        
Weighted average remaining contractual term 1 year 2 months 12 days        
Exercisable stock options outstanding (in shares) 300,000        
Minimum | Restricted Stock Units | 2015 Omnibus Equity Incentive Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Award vesting period 2 years        
Minimum | Summit Materials, LLC | Restricted Stock Units | 2015 Omnibus Equity Incentive Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Award vesting period 2 years        
Maximum | Restricted Stock Units | 2015 Omnibus Equity Incentive Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Award vesting period 3 years        
Maximum | Summit Materials, LLC | Restricted Stock Units | 2015 Omnibus Equity Incentive Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Award vesting period 3 years