Accrued Mining and Landfill Reclamation - Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Jan. 02, 2016
Asset Retirement Obligations [Line Items]
Anticipated costs	$ 63.6	$ 56.7
Accrued expenses
Asset Retirement Obligations [Line Items]
Asset retirement obligation, current	5.1	2.0
Summit Materials, LLC
Asset Retirement Obligations [Line Items]
Asset retirement obligation, current	5.1	2.0
Anticipated costs	$ 63.6	$ 56.7

Current portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Name:	us-gaap_AssetRetirementObligationCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant