v3.22.4
Employee Benefit Plans - Components of Net Periodic Benefit Cost (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2022
Jan. 01, 2022
Jan. 02, 2021
Pension Benefits      
Components of net periodic benefit cost:      
Service cost $ 68 $ 58 $ 71
Interest cost 640 550 733
Amortization of loss 307 428 326
Expected return on plan assets (970) (898) (1,221)
Amortization of prior service credit 0 0 0
Net periodic benefit (expense) cost 45 138 (91)
Pension Benefits | Summit Materials, LLC      
Components of net periodic benefit cost:      
Service cost 68 58 71
Interest cost 640 550 733
Amortization of loss 307 428 326
Expected return on plan assets (970) (898) (1,221)
Amortization of prior service credit 0 0 0
Net periodic benefit (expense) cost 45 138 (91)
Healthcare & Life Ins      
Components of net periodic benefit cost:      
Service cost 35 194 176
Interest cost 239 189 242
Amortization of loss 218 259 89
Expected return on plan assets 0 0 0
Amortization of prior service credit (296) (241) (241)
Net periodic benefit (expense) cost 196 401 266
Healthcare & Life Ins | Summit Materials, LLC      
Components of net periodic benefit cost:      
Service cost 35 194 176
Interest cost 239 189 242
Amortization of loss 218 259 89
Expected return on plan assets 0 0 0
Amortization of prior service credit (296) (241) (241)
Net periodic benefit (expense) cost $ 196 $ 401 $ 266