Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Revenue:
Product	$ 397,726	$ 341,341	$ 622,743	$ 521,443
Service	80,642	71,295	114,669	99,232
Net revenue	478,368	412,636	737,412	620,675
Delivery and subcontract revenue	45,725	32,638	70,958	52,978
Total revenue	524,093	445,274	808,370	673,653
Cost of revenue (excluding items shown separately below):
Product	233,592	202,029	400,560	334,425
Service	56,587	50,471	81,958	74,525
Net cost of revenue	290,179	252,500	482,518	408,950
Delivery and subcontract cost	45,725	32,638	70,958	52,978
Total cost of revenue	335,904	285,138	553,476	461,928
General and administrative expenses	58,086	75,490	116,554	120,860
Depreciation, depletion, amortization and accretion	45,039	37,408	84,787	69,768
Transaction costs	2,620	290	3,893	3,606
Operating loss	82,444	46,948	49,660	17,491
Interest expense	25,986	25,617	50,955	47,194
Loss on debt financings			190
Tax receivable agreement expense	1,525		1,525
Other expense (income), net	(590)	882	(1,247)	548
Loss from operations before taxes	55,523	20,449	(1,763)	(30,251)
Income tax benefit	3,435	(1,056)	1,257	(9,222)
Net loss	52,088	21,505	(3,020)	(21,029)
Net loss attributable to noncontrolling interest in subsidiaries	12	44	(86)	(35)
Net loss attributable to Summit Holdings	2,076	8,090	(490)	(13,247)
Net loss attributable to Summit Materials, Inc. / member of Summit Materials, LLC	50,000	13,371	(2,444)	(7,747)
Summit Materials, LLC
Revenue:
Product	397,726	341,341	622,743	521,443
Service	80,642	71,295	114,669	99,232
Net revenue	478,368	412,636	737,412	620,675
Delivery and subcontract revenue	45,725	32,638	70,958	52,978
Total revenue	524,093	445,274	808,370	673,653
Cost of revenue (excluding items shown separately below):
Product	233,592	202,029	400,560	334,425
Service	56,587	50,471	81,958	74,525
Net cost of revenue	290,179	252,500	482,518	408,950
Delivery and subcontract cost	45,725	32,638	70,958	52,978
Total cost of revenue	335,904	285,138	553,476	461,928
General and administrative expenses	58,086	75,490	116,554	120,860
Depreciation, depletion, amortization and accretion	45,039	37,408	84,787	69,768
Transaction costs	2,620	290	3,893	3,606
Operating loss	82,444	46,948	49,660	17,491
Interest expense	25,772	25,363	50,487	46,649
Loss on debt financings			190
Other expense (income), net	(590)	882	(1,247)	531
Loss from operations before taxes	57,262	20,703	230	(29,689)
Income tax benefit	3,435	(1,056)	1,257	(9,205)
Net loss	53,827	21,759	(1,027)	(20,484)
Net loss attributable to noncontrolling interest	12	44	(86)	(35)
Net loss attributable to Summit Materials, Inc. / member of Summit Materials, LLC	$ 53,815	$ 21,715	$ (941)	$ (20,449)
Common Class A
Loss per share of Class A common stock:
Basic	$ 0.47	$ 0.21	$ (0.02)	$ (0.14)
Diluted	$ 0.46	$ 0.21	$ (0.02)	$ (0.20)
Weighted average shares of Class A common stock:
Basic	106,898,512	62,743,149	106,035,087	56,812,906
Diluted	107,908,888	63,893,909	106,035,087	100,954,233