Income Taxes - Components of Net Deferred Income Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Deferred tax (liabilities) assets:
Net intangible assets	$ 316,950	$ 591,464
Accelerated depreciation	(147,943)	(184,794)
Net operating loss	94,751	71,379
Investment in limited partnership	(14,467)	(13,633)
Mining reclamation reserve	1,239	1,220
Working capital (e.g., accrued compensation, prepaid assets)	(35,237)	(41,529)
Less valuation allowance on loss carryforwards	(1,675)	(502,839)	$ (263,825)
Net deferred tax asset, net	284,092	4,326
Less foreign deferred tax liability included in other non-current liabilities	(3,992)
Net deferred tax asset	280,100	4,326
Income tax expense (benefit)	(283,977)	(5,299)	(18,263)
Summit Materials, LLC
Deferred tax (liabilities) assets:
Net intangible assets	(1,256)	(999)
Accelerated depreciation	(47,920)	(58,094)
Net operating loss	20,671	24,884
Investment in limited partnership	(10,800)	(12,899)
Mining reclamation reserve	488	582
Working capital (e.g., accrued compensation, prepaid assets)	(1,267)	(1,386)
Less valuation allowance on loss carryforwards	(1,675)	(2,677)
Deferred tax liabilities, net	(37,550)	(45,140)
Net deferred tax liability, net	(39,225)	(47,817)
Income tax expense (benefit)	$ (20,345)	$ (5,282)	$ (18,263)