Debt - Summary of Activity for Deferred Financing Fees (Details) - USD ($) $ in Thousands	12 Months Ended
Jan. 02, 2021	Dec. 28, 2019
Deferred finance costs
Beginning balance	$ 15,436	$ 15,475
Loan origination fees	9,605	6,312
Amortization	(3,336)	(3,501)
Write off of deferred financing fees	(3,338)	(2,850)
Ending balance	18,367	15,436
Summit Materials, LLC
Deferred finance costs
Beginning balance	15,436	15,475
Loan origination fees	9,605	6,312
Amortization	(3,336)	(3,501)
Write off of deferred financing fees	(3,338)	(2,850)
Ending balance	$ 18,367	$ 15,436

Amount of amortization expense attributable to debt issuance costs.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

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The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt.

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Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

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