Guarantor and Non-Guarantor Financial Information - Schedule of Condensed Consolidating Statements of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Condensed Consolidating Statements of Operations
Revenue	$ 524,093	$ 445,274	$ 808,370	$ 673,653
Cost of revenue (excluding items shown separately below)	335,904	285,138	553,476	461,928
Depreciation, depletion, amortization and accretion	45,039	37,408	84,787	69,768
Operating loss	82,444	46,948	49,660	17,491
Other expense (income), net	(590)	882	(1,247)	548
Interest expense	25,986	25,617	50,955	47,194
Loss from operations before taxes	55,523	20,449	(1,763)	(30,251)
Income tax (benefit) expense	3,435	(1,056)	1,257	(9,222)
Net income (loss)	52,088	21,505	(3,020)	(21,029)
Net income (loss) attributable to member of Summit Materials, LLC	50,000	13,371	(2,444)	(7,747)
Comprehensive income (loss) income attributable to member of Summit Materials, LLC	54,522	12,987	2,078	(6,933)
Summit Materials, LLC
Condensed Consolidating Statements of Operations
Revenue	524,093	445,274	808,370	673,653
Cost of revenue (excluding items shown separately below)	335,904	285,138	553,476	461,928
General and administrative expenses	60,706	75,780	120,447	124,466
Depreciation, depletion, amortization and accretion	45,039	37,408	84,787	69,768
Operating loss	82,444	46,948	49,660	17,491
Other (income) loss, net			(1,057)
Other expense (income), net	(590)	882	(1,247)	531
Interest expense	25,772	25,363	50,487	46,649
Interest expense (income)	25,772
Loss from operations before taxes	57,262	20,703	230	(29,689)
Income tax (benefit) expense	3,435	(1,056)	1,257	(9,205)
Net income (loss)	53,827	21,759	(1,027)	(20,484)
Net loss attributable to noncontrolling interest	12	44	(86)	(35)
Net income (loss) attributable to member of Summit Materials, LLC	53,815	21,715	(941)	(20,449)
Comprehensive income (loss) income attributable to member of Summit Materials, LLC	57,406	21,292	3,768	(18,464)
Summit Materials, LLC | Eliminations
Condensed Consolidating Statements of Operations
Revenue	(1,654)	(2,042)	(3,162)	(4,007)
Cost of revenue (excluding items shown separately below)	(1,654)	(2,042)	(3,162)	(4,007)
Other (income) loss, net			77,679
Other expense (income), net	93,756	81,394		68,645
Loss from operations before taxes	(93,756)	(81,394)	(77,679)	(68,645)
Net income (loss)	(93,756)	(81,394)	(77,679)	(68,645)
Net loss attributable to noncontrolling interest	12	44	(86)	(35)
Net income (loss) attributable to member of Summit Materials, LLC	(93,768)	(81,438)	(77,593)	(68,610)
Comprehensive income (loss) income attributable to member of Summit Materials, LLC	(90,177)	(81,861)	(72,884)	(66,625)
Summit Materials, LLC | Issuers
Condensed Consolidating Statements of Operations
General and administrative expenses	14,658	37,543	29,707	51,726
Depreciation, depletion, amortization and accretion	663	644	1,321	1,277
Operating loss	(15,321)	(38,187)	(31,028)	(53,003)
Other (income) loss, net			(78,490)
Other expense (income), net	(93,901)	(81,249)		(68,999)
Interest expense		21,347	48,403	36,445
Interest expense (income)	24,765
Loss from operations before taxes	53,815	21,715	(941)	(20,449)
Net income (loss)	53,815	21,715	(941)	(20,449)
Net income (loss) attributable to member of Summit Materials, LLC	53,815	21,715	(941)	(20,449)
Comprehensive income (loss) income attributable to member of Summit Materials, LLC	57,406	21,292	3,768	(18,464)
Summit Materials, LLC | Guarantors
Condensed Consolidating Statements of Operations
Revenue	502,535	434,822	778,911	656,478
Cost of revenue (excluding items shown separately below)	320,315	278,607	532,308	451,496
General and administrative expenses	44,023	36,681	87,397	69,748
Depreciation, depletion, amortization and accretion	43,381	35,629	81,819	66,299
Operating loss	94,816	83,905	77,387	68,935
Other (income) loss, net			9
Other expense (income), net	(226)	863		1,194
Interest expense		3,154	138	8,482
Interest expense (income)	(75)
Loss from operations before taxes	95,117	79,888	77,240	59,259
Income tax (benefit) expense	2,902	(1,195)	722	(9,283)
Net income (loss)	92,215	81,083	76,518	68,542
Net income (loss) attributable to member of Summit Materials, LLC	92,215	81,083	76,518	68,542
Comprehensive income (loss) income attributable to member of Summit Materials, LLC	92,042	82,141	75,933	71,834
Summit Materials, LLC | Non Guarantors
Condensed Consolidating Statements of Operations
Revenue	23,212	12,494	32,621	21,182
Cost of revenue (excluding items shown separately below)	17,243	8,573	24,330	14,439
General and administrative expenses	2,025	1,556	3,343	2,992
Depreciation, depletion, amortization and accretion	995	1,135	1,647	2,192
Operating loss	2,949	1,230	3,301	1,559
Other (income) loss, net			(255)
Other expense (income), net	(219)	(126)		(309)
Interest expense		862	1,946	1,722
Interest expense (income)	1,082
Loss from operations before taxes	2,086	494	1,610	146
Income tax (benefit) expense	533	139	535	78
Net income (loss)	1,553	355	1,075	68
Net income (loss) attributable to member of Summit Materials, LLC	1,553	355	1,075	68
Comprehensive income (loss) income attributable to member of Summit Materials, LLC	$ (1,865)	$ (280)	$ (3,049)	$ (5,209)