Consolidated Statements of Comprehensive (Loss) Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Statement of Comprehensive Income [Abstract]
Net loss	$ (6,282)us-gaap_ProfitLoss	$ (103,679)us-gaap_ProfitLoss	$ (50,577)us-gaap_ProfitLoss
Other comprehensive (loss) income:
Postretirement curtailment adjustment	(1,346)
Postretirement liability adjustment	(3,919)	4,407	(3,648)
Foreign currency translation adjustment	(5,816)
Other comprehensive (loss) income:	(11,081)	4,407	(3,648)
Comprehensive loss	(17,363)	(99,272)	(54,225)
Less comprehensive income attributable to the noncontrolling interest	915	4,434	824
Comprehensive loss attributable to member of Summit Materials, LLC	$ (18,278)us-gaap_ComprehensiveIncomeNetOfTax	$ (103,706)us-gaap_ComprehensiveIncomeNetOfTax	$ (55,049)us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax of gain (loss) adjustment to other comprehensive income (loss) resulting from settlement or curtailment of defined benefit pension and other postretirement defined benefit plans.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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