Guarantor and Non-Guarantor Financial Information - Schedule of Condensed Consolidating Statements of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016
Condensed Consolidating Statements of Operations
Revenue	$ 634,181	$ 529,437	$ 1,442,551	$ 1,203,090
Cost of revenue (excluding items shown separately below)	409,545	335,820	963,021	797,748
Depreciation, depletion, amortization and accretion	48,969	39,427	133,756	109,195
Operating income	113,911	88,410	163,571	105,901
(Loss) income from operations before taxes	(401,509)	62,415	(403,272)	32,164
Income tax expense (benefit)	(483,584)	1,309	(482,327)	(7,913)
Net (loss) income	82,075	61,106	79,055	40,077
Net income (loss) attributable to member of Summit Materials, LLC	79,052	44,820	76,608	37,073
Comprehensive income (loss) income attributable to member of Summit Materials, LLC	83,467	43,936	85,545	37,003
Summit Materials, LLC
Condensed Consolidating Statements of Operations
Revenue	634,181	529,437	1,442,551	1,203,090
Cost of revenue (excluding items shown separately below)	409,545	335,820	963,021	797,748
General and administrative expenses	61,756	65,780	182,203	190,246
Depreciation, depletion, amortization and accretion	48,969	39,427	133,756	109,195
Operating income	113,911	88,410	163,571	105,901
Other (income) expense, net	(2,716)	722	(3,773)	1,253
Interest expense (income)	28,708	25,019	79,195	71,668
(Loss) income from operations before taxes	87,919	62,669	88,149	32,980
Income tax expense (benefit)	5,286	1,309	6,543	(7,896)
Net (loss) income	82,633	61,360	81,606	40,876
Net income (loss) attributable to noncontrolling interest	59	92	(27)	57
Net income (loss) attributable to member of Summit Materials, LLC	82,574	61,268	81,633	40,819
Comprehensive income (loss) income attributable to member of Summit Materials, LLC	87,160	60,017	90,928	41,553
Summit Materials, LLC | Eliminations
Condensed Consolidating Statements of Operations
Revenue	(1,473)	(1,963)	(4,635)	(5,969)
Cost of revenue (excluding items shown separately below)	(1,473)	(1,963)	(4,635)	(5,969)
Other (income) expense, net	125,484	109,656	203,165	178,301
(Loss) income from operations before taxes	(125,484)	(109,656)	(203,165)	(178,301)
Net (loss) income	(125,484)	(109,656)	(203,165)	(178,301)
Net income (loss) attributable to noncontrolling interest	59	92	(27)	57
Net income (loss) attributable to member of Summit Materials, LLC	(125,543)	(109,748)	(203,138)	(178,358)
Comprehensive income (loss) income attributable to member of Summit Materials, LLC	(120,957)	(110,999)	(193,843)	(177,624)
Summit Materials, LLC | Issuers
Condensed Consolidating Statements of Operations
General and administrative expenses	15,011	25,877	44,718	77,603
Depreciation, depletion, amortization and accretion	619	571	1,940	1,848
Operating income	(15,630)	(26,448)	(46,658)	(79,451)
Other (income) expense, net	(126,386)	(109,291)	(204,877)	(178,290)
Interest expense (income)	28,182	21,575	76,586	58,020
(Loss) income from operations before taxes	82,574	61,268	81,633	40,819
Net (loss) income	82,574	61,268	81,633	40,819
Net income (loss) attributable to member of Summit Materials, LLC	82,574	61,268	81,633	40,819
Comprehensive income (loss) income attributable to member of Summit Materials, LLC	87,160	60,017	90,928	41,553
Summit Materials, LLC | Guarantors
Condensed Consolidating Statements of Operations
Revenue	606,046	518,218	1,384,956	1,174,695
Cost of revenue (excluding items shown separately below)	389,716	328,536	922,024	780,031
General and administrative expenses	44,373	38,655	131,770	108,403
Depreciation, depletion, amortization and accretion	47,032	37,819	128,851	104,117
Operating income	124,925	113,208	202,311	182,144
Other (income) expense, net	(1,569)	411	(1,561)	1,605
Interest expense (income)	(670)	2,576	(533)	11,058
(Loss) income from operations before taxes	127,164	110,221	204,405	169,481
Income tax expense (benefit)	4,397	1,212	5,119	(8,071)
Net (loss) income	122,767	109,009	199,286	177,552
Net income (loss) attributable to member of Summit Materials, LLC	122,767	109,009	199,286	177,552
Comprehensive income (loss) income attributable to member of Summit Materials, LLC	122,555	108,949	198,489	180,784
Summit Materials, LLC | Non Guarantors
Condensed Consolidating Statements of Operations
Revenue	29,608	13,182	62,230	34,364
Cost of revenue (excluding items shown separately below)	21,302	9,247	45,632	23,686
General and administrative expenses	2,372	1,248	5,715	4,240
Depreciation, depletion, amortization and accretion	1,318	1,037	2,965	3,230
Operating income	4,616	1,650	7,918	3,208
Other (income) expense, net	(245)	(54)	(500)	(363)
Interest expense (income)	1,196	868	3,142	2,590
(Loss) income from operations before taxes	3,665	836	5,276	981
Income tax expense (benefit)	889	97	1,424	175
Net (loss) income	2,776	739	3,852	806
Net income (loss) attributable to member of Summit Materials, LLC	2,776	739	3,852	806
Comprehensive income (loss) income attributable to member of Summit Materials, LLC	$ (1,598)	$ 2,050	$ (4,646)	$ (3,160)