Unaudited Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Revenue:
Revenue	$ 600,891	$ 600,890	$ 933,530	$ 915,311
Cost of revenue (excluding items shown separately below):
Net cost of revenue	405,493	410,932	672,497	658,793
General and administrative expenses	60,961	61,657	128,571	131,518
Depreciation, depletion, amortization and accretion	53,625	49,731	109,013	96,689
Transaction costs	390	1,291	698	2,557
Operating income	80,422	77,279	22,751	25,754
Interest expense	29,401	28,943	59,506	57,727
Loss on debt financings	0	149	14,565	149
Other income, net	(3,676)	(916)	(6,479)	(8,571)
Income (loss) from operation before taxes	54,697	49,103	(44,841)	(23,551)
Income tax expense (benefit)	16,707	12,190	(11,330)	(4,516)
Net income (loss)	37,990	36,913	(33,511)	(19,035)
Net income (loss) attributable to Summit Holdings	1,580	1,404	(1,149)	(815)
Net income (loss) attributable to Summit Inc.	36,410	35,509	(32,362)	(18,220)
Summit Materials, LLC
Revenue:
Revenue	600,891	600,890	933,530	915,311
Cost of revenue (excluding items shown separately below):
Net cost of revenue	405,493	410,932	672,497	658,793
General and administrative expenses	60,961	61,657	128,571	131,518
Depreciation, depletion, amortization and accretion	53,625	49,731	109,013	96,689
Transaction costs	390	1,291	698	2,557
Operating income	80,422	77,279	22,751	25,754
Interest expense	29,283	28,776	59,220	57,346
Loss on debt financings	0	149	14,565	149
Other income, net	(3,676)	(916)	(6,479)	(8,571)
Income (loss) from operation before taxes	54,815	49,270	(44,555)	(23,170)
Income tax expense (benefit)	1,314	2,668	(6,492)	(1,176)
Net income (loss)	53,501	46,602	(38,063)	(21,994)
Net income (loss) attributable to Summit Inc.	$ 53,501	$ 46,602	$ (38,063)	$ (21,994)
Common Class A
Income (loss) per share of Class A common stock:
Basic (usd per share)	$ 0.32	$ 0.32	$ (0.29)	$ (0.16)
Diluted (usd per share)	$ 0.32	$ 0.32	$ (0.29)	$ (0.16)
Weighted average shares of Class A common stock:
Basic (in shares)	112,070,009	111,564,190	111,940,844	111,111,644
Diluted (in shares)	112,182,555	112,583,321	111,940,844	111,111,644
Product
Revenue:
Revenue	$ 467,637	$ 459,967	$ 739,278	$ 716,774
Cost of revenue (excluding items shown separately below):
Net cost of revenue	294,857	295,147	508,583	492,580
Product | Summit Materials, LLC
Revenue:
Revenue	467,637	459,967	739,278	716,774
Cost of revenue (excluding items shown separately below):
Net cost of revenue	294,857	295,147	508,583	492,580
Service
Revenue:
Revenue	84,954	89,268	119,263	122,377
Cost of revenue (excluding items shown separately below):
Net cost of revenue	62,336	64,130	88,925	90,053
Service | Summit Materials, LLC
Revenue:
Revenue	84,954	89,268	119,263	122,377
Cost of revenue (excluding items shown separately below):
Net cost of revenue	62,336	64,130	88,925	90,053
Excluding delivery and subcontract revenue
Revenue:
Revenue	552,591	549,235	858,541	839,151
Cost of revenue (excluding items shown separately below):
Net cost of revenue	357,193	359,277	597,508	582,633
Excluding delivery and subcontract revenue | Summit Materials, LLC
Revenue:
Revenue	552,591	549,235	858,541	839,151
Cost of revenue (excluding items shown separately below):
Net cost of revenue	357,193	359,277	597,508	582,633
Delivery and subcontract revenue
Revenue:
Revenue	48,300	51,655	74,989	76,160
Cost of revenue (excluding items shown separately below):
Net cost of revenue	48,300	51,655	74,989	76,160
Delivery and subcontract revenue | Summit Materials, LLC
Revenue:
Revenue	48,300	51,655	74,989	76,160
Cost of revenue (excluding items shown separately below):
Net cost of revenue	$ 48,300	$ 51,655	$ 74,989	$ 76,160