Summit Materials (SUM) 10-Q 28 Oct 20 2020 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 26, 2020	Oct. 26, 2020
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 26, 2020
Document Transition Report	false
Entity File Number	001-36873
Entity Registrant Name	SUMMIT MATERIALS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-1984212
Entity Address, Address Line One	1550 Wynkoop Street
Entity Address, Address Line Two	3rd Floor
Entity Address, City or Town	Denver
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80202
City Area Code	303
Local Phone Number	893-0012
Title of 12(b) Security	Class A Common Stock (par value $.01 per share)
Trading Symbol	SUM
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0001621563
Amendment Flag	false
Current Fiscal Year End Date	--12-28
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Common Class A
Document Information [Line Items]
Entity common stock, shares outstanding (in shares)		114,127,616
Common Class B
Document Information [Line Items]
Entity common stock, shares outstanding (in shares)		99
Summit Materials, LLC
Document Information [Line Items]
Entity File Number	333-187556
Entity Registrant Name	SUMMIT MATERIALS, LLC
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-4138486
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0001571371
Amendment Flag	false
Current Fiscal Year End Date	--12-28
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Current assets:
Cash and cash equivalents	$ 288,757	$ 311,319
Accounts receivable, net	309,377	253,256
Costs and estimated earnings in excess of billings	44,001	13,088
Inventories	209,774	204,787
Other current assets	13,632	13,831
Total current assets	865,541	796,281
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization	1,763,066	1,747,449
Goodwill	1,303,086	1,199,699
Finite-Lived Intangible Assets, Net	37,923	23,498
Deferred Income Tax Assets, Net	241,900	212,333
Operating lease right-of-use assets	28,551	32,777
Other assets	52,103	55,519
Total assets	4,292,170	4,067,556
Current liabilities:
Current portion of debt	7,942	7,942
Current portion of acquisition-related liabilities	31,968	32,700
Accounts payable	149,475	116,359
Accrued expenses	144,064	120,005
Current operating lease liabilities	8,193	8,427
Billings in excess of costs and estimated earnings	14,225	13,864
Total current liabilities	355,867	299,297
Long-term debt	1,893,212	1,851,057
Acquisition-related liabilities	12,876	19,801
Tax receivable agreement liability	327,957	326,965
Noncurrent operating lease liabilities	21,327	25,381
Other noncurrent liabilities	111,435	100,282
Total liabilities	2,722,674	2,622,783
Commitments and contingencies (see note 12)
Stockholders’ equity/Member's interest
Additional paid-in capital	1,257,506	1,234,020
Accumulated earnings	291,620	188,805
Accumulated other comprehensive income	975	3,448
Stockholders’ equity	1,551,243	1,427,407
Noncontrolling interest in Summit Holdings	18,253	17,366
Total stockholders’ equity	1,569,496	1,444,773
Total liabilities and stockholders’ equity/member's interest	4,292,170	4,067,556
Summit Materials, LLC
Current assets:
Cash and cash equivalents	288,757	311,319
Accounts receivable, net	309,377	253,256
Costs and estimated earnings in excess of billings	44,001	13,088
Inventories	209,774	204,787
Other current assets	13,632	13,831
Total current assets	865,541	796,281
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization	1,763,066	1,747,449
Goodwill	1,304,086	1,200,699
Finite-Lived Intangible Assets, Net	37,923	23,498
Operating lease right-of-use assets	28,551	32,777
Other assets	52,103	55,519
Total assets	4,051,270	3,856,223
Current liabilities:
Current portion of debt	7,942	7,942
Current portion of acquisition-related liabilities	29,592	30,200
Accounts payable	150,086	116,970
Accrued expenses	144,295	120,237
Current operating lease liabilities	8,193	8,427
Billings in excess of costs and estimated earnings	14,225	13,864
Total current liabilities	354,333	297,640
Long-term debt	1,893,212	1,851,057
Acquisition-related liabilities	12,876	17,666
Noncurrent operating lease liabilities	21,327	25,381
Other noncurrent liabilities	155,011	151,329
Total liabilities	2,436,759	2,343,073
Stockholders’ equity/Member's interest
Members' equity	1,452,758	1,432,718
Accumulated earnings	186,119	101,403
Accumulated other comprehensive income	(24,366)	(20,971)
Total member's interest	1,614,511	1,513,150
Total liabilities and stockholders’ equity/member's interest	4,051,270	3,856,223
Common Class A
Stockholders’ equity/Member's interest
Common stock	1,142	1,134
Common Class B
Stockholders’ equity/Member's interest
Common stock	$ 0	$ 0

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Accumulated depreciation, depletion and amortization	$ 1,088,710	$ 955,815
Accumulated amortization	12,467	10,366
Valuation allowance	1,675	1,675
Summit Materials, LLC
Accumulated depreciation, depletion and amortization	1,088,710	955,815
Accumulated amortization	$ 12,467	$ 10,366
Common Class A
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	114,123,911	113,309,385
Common stock, shares outstanding (in shares)	114,123,911	113,309,385
Common Class B
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	99	99
Common stock, shares outstanding (in shares)	99	99

Unaudited Consolidated Statemen

Unaudited Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Revenue:
Revenue	$ 709,619	$ 732,082	$ 1,707,818	$ 1,665,612
Cost of revenue (excluding items shown separately below):
Net cost of revenue	469,004	482,979	1,165,317	1,155,476
General and administrative expenses	81,499	62,344	218,267	190,915
Depreciation, depletion, amortization and accretion	58,054	55,127	163,760	164,140
Transaction costs	445	751	1,517	1,449
Operating income	100,617	130,881	158,957	153,632
Interest expense	24,623	28,917	78,049	88,423
Loss on debt financings	4,064	0	4,064	14,565
Other income, net	(1,226)	(1,875)	(2,753)	(8,354)
Income from operations before taxes	73,156	103,839	79,597	58,998
Income tax (benefit) expense	(19,613)	45,602	(25,333)	34,272
Net income	92,769	58,237	104,930	24,726
Net income attributable to Summit Holdings	2,039	2,480	2,115	1,331
Net income (loss) attributable to Summit Inc/LLC	90,730	55,757	102,815	23,395
Summit Materials, LLC
Revenue:
Revenue	709,619	732,082	1,707,818	1,665,612
Cost of revenue (excluding items shown separately below):
Net cost of revenue	469,004	482,979	1,165,317	1,155,476
General and administrative expenses	81,499	62,344	218,267	190,915
Depreciation, depletion, amortization and accretion	58,054	55,127	163,760	164,140
Transaction costs	445	751	1,517	1,449
Operating income	100,617	130,881	158,957	153,632
Interest expense	24,561	28,800	77,807	88,020
Loss on debt financings	4,064	0	4,064	14,565
Other income, net	(1,226)	(1,875)	(2,753)	(8,354)
Income from operations before taxes	73,218	103,956	79,839	59,401
Income tax (benefit) expense	(5,106)	18,757	(4,877)	12,265
Net income	78,324	85,199	84,716	47,136
Net income (loss) attributable to Summit Inc/LLC	$ 78,324	$ 85,199	$ 84,716	$ 47,136
Common Class A
Earnings per share of Class A common stock:
Basic (usd per share)	$ 0.79	$ 0.50	$ 0.90	$ 0.21
Diluted (usd per share)	$ 0.79	$ 0.48	$ 0.90	$ 0.21
Weighted average shares of Class A common stock:
Basic (in shares)	114,116,564	112,179,137	113,943,292	112,020,275
Diluted (in shares)	114,472,171	115,505,122	114,457,276	112,497,610
Product
Revenue:
Revenue	$ 540,904	$ 554,721	$ 1,334,471	$ 1,293,999
Cost of revenue (excluding items shown separately below):
Net cost of revenue	331,853	338,119	857,912	846,702
Product | Summit Materials, LLC
Revenue:
Revenue	540,904	554,721	1,334,471	1,293,999
Cost of revenue (excluding items shown separately below):
Net cost of revenue	331,853	338,119	857,912	846,702
Service
Revenue:
Revenue	104,342	111,126	228,421	230,389
Cost of revenue (excluding items shown separately below):
Net cost of revenue	72,778	78,625	162,479	167,550
Service | Summit Materials, LLC
Revenue:
Revenue	104,342	111,126	228,421	230,389
Cost of revenue (excluding items shown separately below):
Net cost of revenue	72,778	78,625	162,479	167,550
Excluding delivery and subcontract revenue
Revenue:
Revenue	645,246	665,847	1,562,892	1,524,388
Cost of revenue (excluding items shown separately below):
Net cost of revenue	404,631	416,744	1,020,391	1,014,252
Excluding delivery and subcontract revenue | Summit Materials, LLC
Revenue:
Revenue	645,246	665,847	1,562,892	1,524,388
Cost of revenue (excluding items shown separately below):
Net cost of revenue	404,631	416,744	1,020,391	1,014,252
Delivery and subcontract revenue
Revenue:
Revenue	64,373	66,235	144,926	141,224
Cost of revenue (excluding items shown separately below):
Net cost of revenue	64,373	66,235	144,926	141,224
Delivery and subcontract revenue | Summit Materials, LLC
Revenue:
Revenue	64,373	66,235	144,926	141,224
Cost of revenue (excluding items shown separately below):
Net cost of revenue	$ 64,373	$ 66,235	$ 144,926	$ 141,224

Unaudited Consolidated Statem_2

Unaudited Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Comprehensive income (loss)
Net income	$ 92,769	$ 58,237	$ 104,930	$ 24,726
Other comprehensive income (loss):
Foreign currency translation adjustment	2,018	(1,328)	(3,395)	3,263
Income (loss) on cash flow hedges	0	155	0	(148)
Less tax effect of other comprehensive (loss) income items	(494)	284	831	(766)
Other comprehensive income (loss)	1,524	(889)	(2,564)	2,349
Comprehensive income	94,293	57,348	102,366	27,075
Less comprehensive income attributable to Summit Holdings	2,091	2,444	2,024	1,423
Comprehensive income attributable to Summit Inc.	92,202	54,904	100,342	25,652
Summit Materials, LLC
Comprehensive income (loss)
Net income	78,324	85,199	84,716	47,136
Other comprehensive income (loss):
Foreign currency translation adjustment	2,018	(1,328)	(3,395)	3,263
Income (loss) on cash flow hedges	0	155	0	(148)
Other comprehensive income (loss)	2,018	(1,173)	(3,395)	3,115
Comprehensive income attributable to Summit Inc.	$ 80,342	$ 84,026	$ 81,321	$ 50,251

Unaudited Consolidated Statem_3

Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
Cash flow from operating activities:
Net income	$ 104,930	$ 24,726
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation, depletion, amortization and accretion	164,397	166,997
Share-based compensation expense	23,119	15,424
Net gain on asset disposals	(5,746)	(8,030)
Non-cash loss on debt financings	4,064	2,850
Change in deferred tax asset, net	(28,968)	32,736
Other	760	(1,609)
Decrease (increase) in operating assets, net of acquisitions and dispositions:
Accounts receivable, net	(48,361)	(121,196)
Inventories	(2,829)	16,296
Costs and estimated earnings in excess of billings	(30,912)	(31,085)
Other current assets	(75)	5,635
Other assets	8,367	4,992
(Decrease) increase in operating liabilities, net of acquisitions and dispositions:
Accounts payable	21,729	52,423
Accrued expenses	3,164	8,447
Billings in excess of costs and estimated earnings	395	618
Tax receivable agreement liability	993	424
Other liabilities	3,012	(5,805)
Net cash provided by operating activities	218,039	163,843
Cash flow from investing activities:
Acquisitions, net of cash acquired	(123,195)	(2,842)
Purchases of property, plant and equipment	(140,006)	(139,762)
Proceeds from the sale of property, plant and equipment	8,848	13,035
Other	1,395	(207)
Net cash used for investing activities	(252,958)	(129,776)
Cash flow from financing activities:
Proceeds from debt issuances	700,000	300,000
Debt issuance costs	(9,565)	(6,312)
Payments on debt	(666,892)	(264,906)
Payments on acquisition-related liabilities	(10,391)	(11,000)
Proceeds from stock option exercises	329	2,559
Other	(908)	(501)
Net cash provided by financing activities	12,573	19,840
Impact of foreign currency on cash	(216)	174
Net (decrease) increase in cash	(22,562)	54,081
Cash and cash equivalents—beginning of period	311,319	128,508
Cash and cash equivalents—end of period	288,757	182,589
Summit Materials, LLC
Cash flow from operating activities:
Net income	84,716	47,136
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation, depletion, amortization and accretion	164,155	166,594
Share-based compensation expense	23,119	15,424
Net gain on asset disposals	(5,746)	(8,030)
Non-cash loss on debt financings	4,064	2,850
Change in deferred tax asset, net	(7,519)	11,153
Other	760	(1,609)
Decrease (increase) in operating assets, net of acquisitions and dispositions:
Accounts receivable, net	(48,361)	(121,196)
Inventories	(2,829)	16,296
Costs and estimated earnings in excess of billings	(30,912)	(31,085)
Other current assets	(75)	5,635
Other assets	8,367	4,992
(Decrease) increase in operating liabilities, net of acquisitions and dispositions:
Accounts payable	21,729	51,728
Accrued expenses	3,164	9,142
Billings in excess of costs and estimated earnings	395	618
Other liabilities	3,012	(5,805)
Net cash provided by operating activities	218,039	163,843
Cash flow from investing activities:
Acquisitions, net of cash acquired	(123,195)	(2,842)
Purchases of property, plant and equipment	(140,006)	(139,762)
Proceeds from the sale of property, plant and equipment	8,848	13,035
Other	1,395	(207)
Net cash used for investing activities	(252,958)	(129,776)
Cash flow from financing activities:
Capital contributions by member	329	2,559
Proceeds from debt issuances	700,000	300,000
Debt issuance costs	(9,565)	(6,312)
Payments on debt	(666,892)	(264,906)
Payments on acquisition-related liabilities	(7,891)	(8,500)
Distributions from partnership	(2,500)	(2,500)
Other	(908)	(501)
Net cash provided by financing activities	12,573	19,840
Impact of foreign currency on cash	(216)	174
Net (decrease) increase in cash	(22,562)	54,081
Cash and cash equivalents—beginning of period	311,319	128,508
Cash and cash equivalents—end of period	$ 288,757	$ 182,589

Unaudited Consolidated Statem_4

Unaudited Consolidated Statements of Changes in Stockholders' Equity / Members' Interest and Redeemable Noncontrolling Interest - USD ($) $ in Thousands	Total	Summit Materials, LLC	Common Class A	Common Class B	Members' equitySummit Materials, LLC	Accumulated Earnings (Deficit)	Accumulated Earnings (Deficit)Summit Materials, LLC	Accumulated other comprehensive income (loss)	Accumulated other comprehensive income (loss)Summit Materials, LLC	Common StockCommon Class A	Common StockCommon Class B	Additional Paid-in Capital	Noncontrolling Interest In Lp
Beginning balance at Dec. 29, 2018	$ 1,342,145					$ 129,739		$ 2,681	$ (23,616)	$ 1,117	$ 0	$ 1,194,204	$ 14,404
Beginning balance at Dec. 29, 2018		$ 1,385,431			$ 1,396,241		$ 12,806		(23,616)
Beginning balance (in shares) at Dec. 29, 2018			111,658,927							111,658,927	99
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net contributed capital		766			766
Net (loss) income	(71,501)	(91,564)				(68,772)	(91,564)						(2,729)
LP Unit exchanges (in shares)										17,500
LP Unit exchanges	0									$ 0		122	(122)
Other comprehensive (loss) income, net of tax	1,650	2,192						1,584	2,192				66
Stock option exercises (in shares)										43,142
Stock option exercises	767									$ 1		766
Distributions		(2,500)			(2,500)
Share-based compensation	5,906	5,906			5,906							5,906
Shares redeemed to settle taxes and other (in shares)										347,962
Shares redeemed to settle taxes and other	(492)	(501)			(501)					$ 3		(495)
Ending balance at Mar. 30, 2019	1,278,475					60,967		4,265		$ 1,121	$ 0	1,200,503	11,619
Ending balance at Mar. 30, 2019		1,299,730			1,399,912		(78,758)		(21,424)
Ending balance (in shares) at Mar. 30, 2019										112,067,531	99
Beginning balance at Dec. 29, 2018	1,342,145					129,739		2,681	(23,616)	$ 1,117	$ 0	1,194,204	14,404
Beginning balance at Dec. 29, 2018		1,385,431			1,396,241		12,806		(23,616)
Beginning balance (in shares) at Dec. 29, 2018			111,658,927							111,658,927	99
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	24,726	47,136
LP Unit exchanges (in shares)			107,336
Other comprehensive (loss) income, net of tax	2,349	3,115
Shares redeemed to settle taxes and other (in shares)			509,735
Ending balance at Sep. 28, 2019	1,386,778					153,134		4,938	(20,501)	$ 1,124	$ 0	1,212,240	15,342
Ending balance at Sep. 28, 2019		1,450,664			1,411,223		59,942		(20,501)
Ending balance (in shares) at Sep. 28, 2019			112,275,998							112,275,998	99
Beginning balance at Mar. 30, 2019	1,278,475					60,967		4,265		$ 1,121	$ 0	1,200,503	11,619
Beginning balance at Mar. 30, 2019		1,299,730			1,399,912		(78,758)		(21,424)
Beginning balance (in shares) at Mar. 30, 2019										112,067,531	99
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net contributed capital		18			18
Net (loss) income	37,990	53,501				36,410	53,501						1,580
Other comprehensive (loss) income, net of tax	1,588	2,096						1,526	2,096				62
Stock option exercises (in shares)										1,019
Stock option exercises	17									$ 0		17
Share-based compensation	4,699	4,699			4,699							4,699
Shares redeemed to settle taxes and other (in shares)										4,944
Shares redeemed to settle taxes and other	2									$ 1		2	(1)
Ending balance at Jun. 29, 2019	1,322,771					97,377		5,791		$ 1,122	$ 0	1,205,221	13,260
Ending balance at Jun. 29, 2019		1,360,044			1,404,629		(25,257)		(19,328)
Ending balance (in shares) at Jun. 29, 2019										112,073,494	99
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net contributed capital		1,775			1,775
Net (loss) income	58,237	85,199				55,757	85,199						2,480
LP Unit exchanges (in shares)										89,836
LP Unit exchanges	0									$ 1		361	(362)
Other comprehensive (loss) income, net of tax	(889)	(1,173)						(853)	(1,173)				(36)
Stock option exercises (in shares)										99,344
Stock option exercises	1,775									$ 1		1,774
Share-based compensation	4,819	4,819			4,819							4,819
Shares redeemed to settle taxes and other (in shares)										13,324
Shares redeemed to settle taxes and other	65											65
Ending balance at Sep. 28, 2019	1,386,778					153,134		4,938	(20,501)	$ 1,124	$ 0	1,212,240	15,342
Ending balance at Sep. 28, 2019		1,450,664			1,411,223		59,942		(20,501)
Ending balance (in shares) at Sep. 28, 2019			112,275,998							112,275,998	99
Beginning balance at Dec. 28, 2019	1,444,773					188,805		3,448	(20,971)	$ 1,134	$ 0	1,234,020	17,366
Beginning balance at Dec. 28, 2019		1,513,150			1,432,718		101,403		(20,971)
Beginning balance (in shares) at Dec. 28, 2019			113,309,385	99						113,309,385	99
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net contributed capital		310			310
Net (loss) income	(46,726)	(63,625)				(44,979)	(63,625)						(1,747)
LP Unit exchanges (in shares)										196,542
LP Unit exchanges	0									$ 2		1,132	(1,134)
Other comprehensive (loss) income, net of tax	(6,313)	(8,359)						(6,093)	(8,359)				(220)
Stock option exercises (in shares)										13,335
Stock option exercises	310									$ 0		310
Distributions		(2,500)			(2,500)
Share-based compensation	4,905	4,905			4,905							4,905
Shares redeemed to settle taxes and other (in shares)										591,335
Shares redeemed to settle taxes and other	(1,090)	(908)			(908)					$ 6		(1,096)
Ending balance at Mar. 28, 2020	1,395,859					143,826		(2,645)		$ 1,142	$ 0	1,239,271	14,265
Ending balance at Mar. 28, 2020		1,442,973			1,434,525		37,778		(29,330)
Ending balance (in shares) at Mar. 28, 2020										114,110,597	99
Beginning balance at Dec. 28, 2019	1,444,773					188,805		3,448	(20,971)	$ 1,134	$ 0	1,234,020	17,366
Beginning balance at Dec. 28, 2019		1,513,150			1,432,718		101,403		(20,971)
Beginning balance (in shares) at Dec. 28, 2019			113,309,385	99						113,309,385	99
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	104,930	84,716
LP Unit exchanges (in shares)			196,542
Other comprehensive (loss) income, net of tax	(2,564)	(3,395)
Stock option exercises (in shares)			14,404
Shares redeemed to settle taxes and other (in shares)			603,580
Ending balance at Sep. 26, 2020	1,569,496					291,620		975	(24,366)	$ 1,142	$ 0	1,257,506	18,253
Ending balance at Sep. 26, 2020		1,614,511			1,452,758		186,119		(24,366)
Ending balance (in shares) at Sep. 26, 2020			114,123,911	99						114,123,911	99
Beginning balance at Mar. 28, 2020	1,395,859					143,826		(2,645)		$ 1,142	$ 0	1,239,271	14,265
Beginning balance at Mar. 28, 2020		1,442,973			1,434,525		37,778		(29,330)
Beginning balance (in shares) at Mar. 28, 2020										114,110,597	99
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	58,887	70,017				57,064	70,017						1,823
Other comprehensive (loss) income, net of tax	2,225	2,946						2,148	2,946				77
Share-based compensation	4,892	4,892			4,892							4,892
Shares redeemed to settle taxes and other (in shares)										1,351
Shares redeemed to settle taxes and other	0											0
Ending balance at Jun. 27, 2020	1,461,863					200,890		(497)		$ 1,142	$ 0	1,244,163	16,165
Ending balance at Jun. 27, 2020		1,520,828			1,439,417		107,795		(26,384)
Ending balance (in shares) at Jun. 27, 2020										114,111,948	99
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net contributed capital		19
Net (loss) income	92,769	78,324				90,730	78,324						2,039
Other comprehensive (loss) income, net of tax	1,524	2,018						1,472	2,018				52
Stock option exercises (in shares)										1,069
Stock option exercises	18									$ 0		18
Share-based compensation	13,322	13,322			13,322							13,322
Shares redeemed to settle taxes and other (in shares)										10,894
Shares redeemed to settle taxes and other	0									$ 0		3
Ending balance at Sep. 26, 2020	$ 1,569,496					$ 291,620		$ 975	(24,366)	$ 1,142	$ 0	$ 1,257,506	$ 18,253
Ending balance at Sep. 26, 2020		$ 1,614,511			$ 1,452,758		$ 186,119		$ (24,366)
Ending balance (in shares) at Sep. 26, 2020			114,123,911	99						114,123,911	99

SUMMARY OF ORGANIZATION AND SIG

SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 26, 2020
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES Summit Materials, Inc. (“Summit Inc.” and, together with its subsidiaries, “Summit,” “we,” “us,” “our” or the “Company”) is a vertically-integrated construction materials company. The Company is engaged in the production and sale of aggregates, cement, ready-mix concrete, asphalt paving mix and concrete products and owns and operates quarries, sand and gravel pits, two cement plants, cement distribution terminals, ready-mix concrete plants, asphalt plants and landfill sites. It is also engaged in paving and related services. The Company’s three operating and reporting segments are the West, East and Cement segments. Substantially all of the Company’s construction materials, products and services are produced, consumed and performed outdoors, primarily in the spring, summer and fall. Seasonal changes and other weather-related conditions can affect the production and sales volumes of its products and delivery of services. Therefore, the financial results for any interim period are typically not indicative of the results expected for the full year. Furthermore, the Company’s sales and earnings are sensitive to national, regional and local economic conditions, weather conditions and to cyclical changes in construction spending, among other factors. Summit Inc. is a holding corporation operating and controlling all of the business and affairs of Summit Materials Holdings L.P. (“Summit Holdings”) and its subsidiaries and, through Summit Holdings, conducts its business. Summit Inc. owns the majority of the partnership interests of Summit Holdings (see Note 9, Stockholders’ Equity). Summit Materials, LLC (“Summit LLC”) an indirect wholly owned subsidiary of Summit Holdings, conducts the majority of our operations. Summit Materials Finance Corp. (“Summit Finance”), an indirect wholly owned subsidiary of Summit LLC, has jointly issued our Senior Notes as described below. Basis of Presentation —These unaudited consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures typically included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. These unaudited consolidated financial statements should be read in conjunction with the Company's audited consolidated financial statements and the notes thereto as of and for the year ended December 28, 2019. The Company continues to follow the accounting policies set forth in those audited consolidated financial statements. Management believes that these consolidated interim financial statements include all adjustments, normal and recurring in nature, that are necessary to present fairly the financial position of the Company as of September 26, 2020, the results of operations for the three and nine months ended September 26, 2020 and September 28, 2019 and cash flows for the nine months ended September 26, 2020 and September 28, 2019. Principles of Consolidation —The consolidated financial statements include the accounts of Summit Inc. and its majority owned subsidiaries. All intercompany balances and transactions have been eliminated. For a summary of the changes in Summit Inc.’s ownership of Summit Holdings, see Note 9, Stockholders’ Equity. Use of Estimates —Preparation of these consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities and reported amounts of revenue and expenses. Such estimates include the valuation of accounts receivable, inventories, valuation of deferred tax assets, goodwill, intangibles and other long-lived assets, tax receivable agreement ("TRA") liability, pension and other postretirement obligations and asset retirement obligations. Estimates also include revenue earned on contracts and costs to complete contracts. Most of the Company’s paving and related services are performed under fixed unit-price contracts with state and local governmental entities. Management regularly evaluates its estimates and assumptions based on historical experience and other factors, including the current economic environment. As future events and their effects cannot be determined with precision, actual results can differ significantly from estimates made. Changes in estimates, including those resulting from continuing changes in the economic environment, are reflected in the Company’s consolidated financial statements when the change in estimate occurs. Business and Credit Concentrations— The Company’s operations are conducted primarily across 23 U.S. states and in British Columbia, Canada, with the most significant revenue generated in Texas, Kansas, Utah and Missouri. The Company’s accounts receivable consist primarily of amounts due from customers within these areas. Therefore, collection of these accounts is dependent on the economic conditions in the aforementioned states, as well as specific situations affecting individual customers. Credit granted within the Company’s trade areas has been granted to many customers, and management does not believe that a significant concentration of credit exists with respect to any individual customer or group of customers. No single customer accounted for more than 10% of the Company’s total revenue in the three and nine months ended September 26, 2020 or September 28, 2019. Revenue Recognition— We earn revenue from the sale of products, which primarily include aggregates, cement, ready-mix concrete and asphalt, but also include concrete products, and from the provision of services, which are primarily paving and related services. Products: Revenue for product sales is recognized when evidence of an arrangement exists and when control passes, which generally is when the product is shipped. Services: We earn revenue from the provision of services, which are primarily paving and related services, which are typically calculated using monthly progress based on the percentage of completion or a customer’s engineer review of progress. The majority of our construction service contracts are completed within one year, but may occasionally extend beyond this time frame. The majority of our construction service contracts are for work that occurs mostly during the spring, summer and fall. We generally measure progress toward completion on long-term paving and related services contracts based on the proportion of costs incurred to date relative to total estimated costs at completion. The percentage of completion method of accounting involves the use of various estimating techniques to project costs at completion, and in some cases includes estimates of recoveries asserted against the customer for changes in specifications or other disputes. Earnings per Share— The Company computes basic earnings per share attributable to stockholders by dividing income attributable to Summit Inc. by the weighted-average shares of Class A common stock outstanding. Diluted earnings per share reflects the potential dilution beyond shares for basic earnings per share that could occur if securities or other contracts to issue common stock were exercised, converted into common stock, or resulted in the issuance of common stock that would have shared in the Company’s earnings. Since the Class B common stock has no economic value, those shares are not included in the weighted-average common share amount for basic or diluted earnings per share. In addition, as the shares of Class A common stock are issued by Summit Inc., the earnings and equity interests of noncontrolling interests are not included in basic earnings per share. Tax Receivable Agreement —When Class A limited partnership units of Summit Holdings (“LP Units”) are exchanged for shares of Class A common stock of Summit Inc. or Summit Inc. purchases LP Units for cash, this results in increases in Summit Inc.’s share of the tax basis of the tangible and intangible assets, which increases the tax depreciation and amortization deductions that otherwise would not have been available to Summit Inc. These increases in tax basis and tax depreciation and amortization deductions are expected to reduce the amount of cash taxes that we would otherwise be required to pay in the future. Prior to our initial public offering (“IPO”), we entered into a TRA with the pre-IPO owners that requires us to pay the pre-IPO owners or their permitted assignees 85% of the amount of cash savings, if any, in U.S. federal, state, and local income tax that we actually realize as a result of these exchanges. These benefits include (1) increases in the tax basis of tangible and intangible assets of Summit Holdings and certain other tax benefits related to entering into the TRA, (2) tax benefits attributable to payments under the TRA, or (3) under certain circumstances such as an early termination of the TRA, we are deemed to realize, as a result of the increases in tax basis in connection with exchanges by the pre-IPO owners described above and certain other tax benefits attributable to payments under the TRA. We periodically evaluate the realizability of the deferred tax assets resulting from the exchange of LP Units for Class A common stock. If the deferred tax assets are determined to be realizable, we then assess whether payment of amounts under the TRA have become probable. If so, we record a TRA liability equal to 85% of such deferred tax assets, and the remaining 15% as an increase to additional paid-in capital. If a deferred tax asset subject to the TRA is determined not to be realizable and therefore subject to a valuation allowance, we do not record a TRA liability for such deferred tax assets. In subsequent periods, we assess the realizability of all of our deferred tax assets subject to the TRA. Should we determine a deferred tax asset with a valuation allowance is realizable in a subsequent period, the related valuation allowance will be released and consideration of a corresponding TRA liability will be assessed. The realizability of deferred tax assets, including those subject to the TRA, is dependent upon the generation of future taxable income during the periods in which those deferred tax assets become deductible and consideration of prudent and feasible tax-planning strategies. The measurement of the TRA liability is accounted for as a contingent liability. Therefore, once we determine that a payment to a pre-IPO owner has become probable and can be estimated, the estimate of payment will be accrued. New Accounting Standards — In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which reduces the accounting complexity of implementing a cloud computing service arrangement. The ASU aligns the capitalization of implementation costs among hosting arrangements and costs incurred to develop internal-use software. We adopted this ASU in the first quarter of 2020 and the adoption of this ASU did not have a material impact on the consolidated financial statements.
Summit Materials, LLC
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES Summit Materials, LLC (“Summit LLC” and, together with its subsidiaries, “Summit,” “we,” “us,” “our” or the “Company”) is a vertically-integrated construction materials company. The Company is engaged in the production and sale of aggregates, cement, ready-mix concrete, asphalt paving mix and concrete products and owns and operates quarries, sand and gravel pits, two cement plants, cement distribution terminals, ready-mix concrete plants, asphalt plants and landfill sites. It is also engaged in paving and related services. The Company’s three operating and reporting segments are the West, East and Cement segments. Substantially all of the Company’s construction materials, products and services are produced, consumed and performed outdoors, primarily in the spring, summer and fall. Seasonal changes and other weather-related conditions can affect the production and sales volumes of its products and delivery of services. Therefore, the financial results for any interim period are typically not indicative of the results expected for the full year. Furthermore, the Company’s sales and earnings are sensitive to national, regional and local economic conditions, weather conditions and to cyclical changes in construction spending, among other factors. Summit LLC is a wholly owned indirect subsidiary of Summit Materials Holdings L.P. (“Summit Holdings”), whose primary owner is Summit Materials, Inc. (“Summit Inc.”). Summit Inc. was formed as a Delaware corporation on September 23, 2014. Its sole material asset is a controlling equity interest in Summit Holdings. Pursuant to a reorganization into a holding company structure (the “Reorganization”) consummated in connection with Summit Inc.’s March 2015 initial public offering, Summit Inc. became a holding corporation operating and controlling all of the business and affairs of Summit Holdings and its subsidiaries, including Summit LLC. Basis of Presentation —These unaudited consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures typically included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. These unaudited consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto as of and for the year ended December 28, 2019. The Company continues to follow the accounting policies set forth in those audited consolidated financial statements. Management believes that these consolidated interim financial statements include all adjustments, normal and recurring in nature, that are necessary to present fairly the financial position of the Company as of September 26, 2020, the results of operations for the three and nine months ended September 26, 2020 and September 28, 2019 and cash flows for the nine months ended September 26, 2020 and September 28, 2019. Use of Estimates —Preparation of these consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities and reported amounts of revenue and expenses. Such estimates include the valuation of accounts receivable, inventories, valuation of deferred tax assets, goodwill, intangibles and other long-lived assets, pension and other postretirement obligations and asset retirement obligations. Estimates also include revenue earned on contracts and costs to complete contracts. Most of the Company’s paving and related services are performed under fixed unit-price contracts with state and local governmental entities. Management regularly evaluates its estimates and assumptions based on historical experience and other factors, including the current economic environment. As future events and their effects cannot be determined with precision, actual results can differ significantly from estimates made. Changes in estimates, including those resulting from continuing changes in the economic environment, are reflected in the Company’s consolidated financial statements when the change in estimate occurs. Business and Credit Concentrations— The Company’s operations are conducted primarily across 23 U.S. states and in British Columbia, Canada, with the most significant revenue generated in Texas, Kansas, Utah and Missouri. The Company’s accounts receivable consist primarily of amounts due from customers within these areas. Therefore, collection of these accounts is dependent on the economic conditions in the aforementioned states, as well as specific situations affecting individual customers. Credit granted within the Company’s trade areas has been granted to many customers, and management does not believe that a significant concentration of credit exists with respect to any individual customer or group of customers. No single customer accounted for more than 10% of the Company’s total revenue in the three and nine months ended September 26, 2020 or September 28, 2019. Revenue Recognition— We earn revenue from the sale of products, which primarily include aggregates, cement, ready-mix concrete and asphalt, but also include concrete products, and from the provision of services, which are primarily paving and related services. Products: Revenue for product sales is recognized when evidence of an arrangement exists and when control passes, which generally is when the product is shipped. Services: We earn revenue from the provision of services, which are primarily paving and related services, which are typically calculated using monthly progress based on the percentage of completion or a customer’s engineer review of progress. The majority of our construction service contracts are completed within one year, but may occasionally extend beyond this time frame. The majority of our construction service contracts are for work that occurs mostly during the spring, summer and fall. We generally measure progress toward completion on long-term paving and related services contracts based on the proportion of costs incurred to date relative to total estimated costs at completion. The percentage of completion method of accounting involves the use of various estimating techniques to project costs at completion, and in some cases includes estimates of recoveries asserted against the customer for changes in specifications or other disputes. New Accounting Standards— In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which reduces the accounting complexity of implementing a cloud computing service arrangement. The ASU aligns the capitalization of implementation costs among hosting arrangements and costs incurred to develop internal-use software. We adopted this ASU in the first quarter of 2020 and the adoption of this ASU did not have a material impact on the consolidated financial statements.

ACQUISITIONS, GOODWILL AND INTA

ACQUISITIONS, GOODWILL AND INTANGIBLES	9 Months Ended
	Sep. 26, 2020
Business Acquisition [Line Items]
ACQUISITIONS, GOODWILL AND INTANGIBLES	ACQUISITIONS, GOODWILL AND INTANGIBLES The Company has completed numerous acquisitions since its formation, which have been financed through a combination of debt and equity funding and available cash. The operations of each acquisition have been included in the Company’s consolidated results of operations since the respective closing dates of the acquisitions. The Company measures all assets acquired and liabilities assumed at their acquisition-date fair value. Goodwill acquired during a business combination has an indefinite life and is not amortized. The following table summarizes the Company’s acquisitions by region and period: Nine months ended Year ended September 26, 2020 December 28, 2019 West 2 2 East 1 — The purchase price allocation, primarily the valuation of property, plant and equipment for the acquisitions completed during the nine months ended September 26, 2020, as well as the acquisitions completed during 2019 that occurred after September 28, 2019, have not yet been finalized due to the recent timing of the acquisitions, status of the valuation of property, plant and equipment and finalization of related tax returns. The following table summarizes aggregated information regarding the fair values of the assets acquired and liabilities assumed as of the respective acquisition dates: Nine months ended Year ended September 26, 2020 December 28, 2019 Financial assets $ 8,866 $ — Inventories 2,328 52 Property, plant and equipment 17,069 3,542 Other assets 758 — Financial liabilities (3,980) (36) Other long-term liabilities (6,473) — Net assets acquired 18,568 3,558 Goodwill 105,280 1,834 Purchase price 123,848 5,392 Other (652) — Net cash paid for acquisitions $ 123,196 $ 5,392 Changes in the carrying amount of goodwill, by reportable segment, from December 28, 2019 to September 26, 2020 are summarized as follows: West East Cement Total Balance—December 28, 2019 $ 584,617 $ 410,426 $ 204,656 $ 1,199,699 Acquisitions (1) 105,298 — — 105,298 Foreign currency translation adjustments (1,911) — — (1,911) Balance—September 26, 2020 $ 688,004 $ 410,426 $ 204,656 $ 1,303,086 _______________________________________________________________________ (1) Reflects goodwill from acquisitions completed during the nine months ended September 26, 2020 and working capital adjustments from prior year acquisitions. The Company’s intangible assets subject to amortization are primarily composed of operating permits, mineral lease agreements and reserve rights. Operating permits relate to permitting and zoning rights acquired outside of a business combination. The assets related to mineral lease agreements reflect the submarket royalty rates paid under agreements, primarily for extracting aggregates. The values were determined as of the respective acquisition dates by a comparison of market-royalty rates. The reserve rights relate to aggregate reserves to which the Company has the rights of ownership, but does not own the reserves. The intangible assets are amortized on a straight-line basis over the lives of the leases or permits. The following table shows intangible assets by type and in total: September 26, 2020 December 28, 2019 Gross Accumulated Net Gross Accumulated Net Operating permits $ 23,345 $ (1,162) $ 22,183 $ 6,609 $ (290) $ 6,319 Mineral leases 19,225 (7,286) 11,939 19,064 (6,408) 12,656 Reserve rights 6,234 (2,444) 3,790 6,234 (2,248) 3,986 Trade names 1,000 (1,000) — 1,000 (958) 42 Other 586 (575) 11 957 (462) 495 Total intangible assets $ 50,390 $ (12,467) $ 37,923 $ 33,864 $ (10,366) $ 23,498 Amortization expense totaled $0.7 million and $2.3 million for the three and nine months ended September 26, 2020, respectively, and $0.6 million and $1.4 million for the three and nine months ended September 28, 2019, respectively. The estimated amortization expense for the intangible assets for each of the five years subsequent to September 26, 2020 is as follows: 2020 (three months) $ 686 2021 2,719 2022 2,723 2023 2,590 2024 2,495 2025 2,450 Thereafter 24,260 Total $ 37,923
Summit Materials, LLC
Business Acquisition [Line Items]
GOODWILL AND INTANGIBLES	GOODWILL AND INTANGIBLES The Company has completed numerous acquisitions since its formation, which have been financed through a combination of debt and equity funding and available cash. The operations of each acquisition have been included in the Company’s consolidated results of operations since the respective closing dates of the acquisitions. The Company measures all assets acquired and liabilities assumed at their acquisition-date fair value. Goodwill acquired during a business combination has an indefinite life and is not amortized. The following table summarizes the Company’s acquisitions by region and period: Nine months ended Year ended September 26, 2020 December 28, 2019 West 2 2 East 1 — The purchase price allocation, primarily the valuation of property, plant and equipment for the acquisitions completed during the nine months ended September 26, 2020, as well as the acquisitions completed during 2019 that occurred after September 28, 2019, have not yet been finalized due to the recent timing of the acquisitions, status of the valuation of property, plant and equipment and finalization of related tax returns. The following table summarizes aggregated information regarding the fair values of the assets acquired and liabilities assumed as of the respective acquisition dates: Nine months ended Year ended September 26, 2020 December 28, 2019 Financial assets $ 8,866 $ — Inventories 2,328 52 Property, plant and equipment 17,069 3,542 Other assets 758 — Financial liabilities (3,980) (36) Other long-term liabilities (6,473) — Net assets acquired 18,568 3,558 Goodwill 105,280 1,834 Purchase price 123,848 5,392 Other (652) — Net cash paid for acquisitions $ 123,196 $ 5,392 Changes in the carrying amount of goodwill, by reportable segment, from December 28, 2019 to September 26, 2020 are summarized as follows: West East Cement Total Balance—December 28, 2019 $ 585,617 $ 410,426 $ 204,656 $ 1,200,699 Acquisitions (1) 105,298 — — 105,298 Foreign currency translation adjustments (1,911) — — (1,911) Balance—September 26, 2020 $ 689,004 $ 410,426 $ 204,656 $ 1,304,086 _______________________________________________________________________ (1) Reflects goodwill from acquisitions completed during the nine months ended September 26, 2020 and working capital adjustments from prior year acquisitions. The Company’s intangible assets subject to amortization are primarily composed of operating permits, mineral lease agreements and reserve rights. Operating permits relate to permitting and zoning rights acquired outside of a business combination. The assets related to mineral lease agreements reflect the submarket royalty rates paid under agreements, primarily for extracting aggregates. The values were determined as of the respective acquisition dates by a comparison of market-royalty rates. The reserve rights relate to aggregate reserves to which the Company has the rights of ownership, but does not own the reserves. The intangible assets are amortized on a straight-line basis over the lives of the leases or permits. The following table shows intangible assets by type and in total: September 26, 2020 December 28, 2019 Gross Accumulated Net Gross Accumulated Net Operating permits $ 23,345 $ (1,162) $ 22,183 $ 6,609 $ (290) $ 6,319 Mineral leases 19,225 (7,286) 11,939 19,064 (6,408) 12,656 Reserve rights 6,234 (2,444) 3,790 6,234 (2,248) 3,986 Trade names 1,000 (1,000) — 1,000 (958) 42 Other 586 (575) 11 957 (462) 495 Total intangible assets $ 50,390 $ (12,467) $ 37,923 $ 33,864 $ (10,366) $ 23,498 Amortization expense totaled $0.7 million and $2.3 million for the three and nine months ended September 26, 2020, respectively, and $0.6 million and $1.4 million for the three and nine months ended September 28, 2019, respectively. The estimated amortization expense for the intangible assets for each of the five years subsequent to September 26, 2020 is as follows: 2020 (three months) $ 686 2021 2,719 2022 2,723 2023 2,590 2024 2,495 2025 2,450 Thereafter 24,260 Total $ 37,923

REVENUE RECOGNITION

REVENUE RECOGNITION	9 Months Ended
	Sep. 26, 2020
Revenue from External Customer [Line Items]
REVENUE RECOGNITION	REVENUE RECOGNITION We derive our revenue predominantly by selling construction materials, products and providing paving and related services. Construction materials consist of aggregates and cement. Products consist of related downstream products, including ready-mix concrete, asphalt paving mix and concrete products. Paving and related service revenue is generated primarily from the asphalt paving services that we provide. Revenue by product for the three and nine months ended September 26, 2020 and September 28, 2019 is as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Revenue by product*: Aggregates $ 136,396 $ 137,528 $ 362,546 $ 354,050 Cement 82,698 92,482 188,854 202,780 Ready-mix concrete 179,124 172,758 488,710 444,258 Asphalt 128,125 137,753 255,992 254,156 Paving and related services 136,191 138,083 280,446 267,732 Other 47,085 53,478 131,270 142,636 Total revenue $ 709,619 $ 732,082 $ 1,707,818 $ 1,665,612 *Revenue from liquid asphalt terminals is included in asphalt revenue. Accounts receivable, net consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Trade accounts receivable $ 231,663 $ 191,672 Construction contract receivables 62,183 47,966 Retention receivables 18,501 17,808 Receivables from related parties 1,918 1,596 Accounts receivable 314,265 259,042 Less: Allowance for doubtful accounts (4,888) (5,786) Accounts receivable, net $ 309,377 $ 253,256 Retention receivables are amounts earned by the Company but held by customers until paving and related service contracts and projects are near completion or fully completed. Amounts are generally billed and collected within one year.
Summit Materials, LLC
Revenue from External Customer [Line Items]
REVENUE RECOGNITION	REVENUE RECOGNITION We derive our revenue predominantly by selling construction materials, products and providing paving and related services. Construction materials consist of aggregates and cement. Products consist of related downstream products, including ready-mix concrete, asphalt paving mix and concrete products. Paving and related service revenue is generated primarily from the asphalt paving services that we provide. Revenue by product for the three and nine months ended September 26, 2020 and September 28, 2019 is as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Revenue by product*: Aggregates $ 136,396 $ 137,528 $ 362,546 $ 354,050 Cement 82,698 92,482 188,854 202,780 Ready-mix concrete 179,124 172,758 488,710 444,258 Asphalt 128,125 137,753 255,992 254,156 Paving and related services 136,191 138,083 280,446 267,732 Other 47,085 53,478 131,270 142,636 Total revenue $ 709,619 $ 732,082 $ 1,707,818 $ 1,665,612 *Revenue from liquid asphalt terminals is included in asphalt revenue. Accounts receivable, net consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Trade accounts receivable $ 231,663 $ 191,672 Construction contract receivables 62,183 47,966 Retention receivables 18,501 17,808 Receivables from related parties 1,918 1,596 Accounts receivable 314,265 259,042 Less: Allowance for doubtful accounts (4,888) (5,786) Accounts receivable, net $ 309,377 $ 253,256 Retention receivables are amounts earned by the Company but held by customers until paving and related service contracts and projects are near completion or fully completed. Amounts are generally billed and collected within one year.

INVENTORIES

INVENTORIES	9 Months Ended
	Sep. 26, 2020
Inventory [Line Items]
INVENTORIES	INVENTORIES Inventories consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Aggregate stockpiles $ 143,271 $ 140,461 Finished goods 31,657 33,023 Work in process 10,062 7,664 Raw materials 24,784 23,639 Total $ 209,774 $ 204,787
Summit Materials, LLC
Inventory [Line Items]
INVENTORIES	INVENTORIES Inventories consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Aggregate stockpiles $ 143,271 $ 140,461 Finished goods 31,657 33,023 Work in process 10,062 7,664 Raw materials 24,784 23,639 Total $ 209,774 $ 204,787

ACCRUED EXPENSES

ACCRUED EXPENSES	9 Months Ended
	Sep. 26, 2020
Schedule Of Accrued Expenses [Line Items]
ACCRUED EXPENSES	ACCRUED EXPENSES Accrued expenses consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Interest $ 11,413 $ 26,892 Payroll and benefits 37,862 29,356 Finance lease obligations 24,868 16,007 Insurance 16,888 14,968 Non-income taxes 18,949 7,666 Deferred asset purchase payments 9,686 3,525 Professional fees 788 902 Other (1) 23,610 20,689 Total $ 144,064 $ 120,005 (1) Consists primarily of current portion of asset retirement obligations and miscellaneous accruals.
Summit Materials, LLC
Schedule Of Accrued Expenses [Line Items]
ACCRUED EXPENSES	ACCRUED EXPENSES Accrued expenses consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Interest $ 11,413 $ 26,892 Payroll and benefits 37,862 29,356 Finance lease obligations 24,868 16,007 Insurance 16,888 14,968 Non-income taxes 19,180 7,898 Deferred asset purchase payments 9,686 3,525 Professional fees 788 902 Other (1) 23,610 20,689 Total $ 144,295 $ 120,237 _______________________________________________________________________ (1) Consists primarily of current portion of asset retirement obligations and miscellaneous accruals.

DEBT

DEBT	9 Months Ended
	Sep. 26, 2020
Debt Instrument [Line Items]
DEBT	DEBT Debt consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Term Loan, due 2024: $619.5 million and $624.3 million, net of $0.9 million and $1.1 million discount at September 26, 2020 and December 28, 2019, respectively $ 618,545 $ 623,140 6 1 ⁄ 8 % Senior Notes, due 2023: $650.0 million, net of $0.9 million discount at December 28, 2019 — 649,133 5 1 ⁄ 8 % Senior Notes, due 2025 300,000 300,000 6 1 ⁄ 2 % Senior Notes, due 2027 300,000 300,000 5 1 ⁄ 4 % Senior Notes, due 2029 700,000 — Total 1,918,545 1,872,273 Current portion of long-term debt 7,942 7,942 Long-term debt $ 1,910,603 $ 1,864,331 The contractual payments of long-term debt, including current maturities, for the five years subsequent to September 26, 2020, are as follows: 2020 (three months) $ 3,177 2021 6,353 2022 6,354 2023 6,354 2024 597,253 2025 300,000 Thereafter 1,000,000 Total 1,919,491 Less: Original issue net discount (946) Less: Capitalized loan costs (17,391) Total debt $ 1,901,154 Senior Notes —On August 11, 2020, Summit LLC and Summit Finance (together, the “Issuers”) issued $700.0 million in aggregate principal amount of 5.250% senior notes due January 15, 2029 (the “2029 Notes”). The 2029 Notes were issued at 100.0% of their par value with proceeds of $690.4 million, net of related fees and expenses. The 2029 Notes were issued under an indenture dated August 11, 2020 (the "2020 Indenture"). The 2020 Indenture contains covenants limiting, among other things, Summit LLC and its restricted subsidiaries’ ability to incur additional indebtedness or issue certain preferred shares, pay dividends, redeem stock or make other distributions, make certain investments, sell or transfer certain assets, create liens, consolidate, merge, sell or otherwise dispose of all or substantially all of its assets, enter into certain transactions with affiliates, and designate subsidiaries as unrestricted subsidiaries. The 2020 Indenture also contains customary events of default. Interest on the 2029 Notes is payable semi-annually on January 15 and July 15 of each year commencing on January 15, 2021. In August 2020, using the proceeds from the 2029 Notes, all of the outstanding $650.0 million 6.125% senior notes due 2023 (the “2023 Notes”) were redeemed at a price equal to par and the indenture under which the 2023 Notes were issued was satisfied and discharged. As a result of the extinguishment, charges of $4.1 million were recognized in the quarter ended September 26, 2020, which included charges of $0.8 million for the write-off of original issue discount and $3.3 million for the write-off of deferred financing fees. On March 15, 2019, the Issuers issued $300.0 million in aggregate principal amount of 6.500% senior notes due March 15, 2027 (the “2027 Notes”). The 2027 Notes were issued at 100.0% of their par value with proceeds of $296.3 million, net of related fees and expenses. The 2027 Notes were issued under an indenture dated March 25, 2019, the terms of which are generally consistent with the 2020 Indenture. Interest on the 2027 Notes is payable semi-annually on March 15 and September 15 of each year commencing on September 15, 2019. In March 2019, using the proceeds from the 2027 Notes, all of the outstanding $250.0 million 8.500% senior notes due 2022 (the “2022 Notes”) were redeemed at a price equal to par plus an applicable premium and the indenture under which the 2022 Notes were issued was satisfied and discharged. As a result of the extinguishment, charges of $14.6 million were recognized in the quarter ended March 30, 2019, which included charges of $11.7 million for the applicable redemption premium and $2.9 million for the write-off of deferred financing fees. In 2017, the Issuers issued $300.0 million of 5.125% senior notes due June 1, 2025 (the “2025 Notes”). The 2025 Notes were issued at 100.0% of their par value with proceeds of $295.4 million, net of related fees and expenses. The 2025 Notes were issued under an indenture dated June 1, 2017, the terms of which are generally consistent with the 2020 Indenture. Interest on the 2025 Notes is payable semi-annually on June 1 and December 1 of each year commencing on December 1, 2017. In 2015, the Issuers issued $650.0 million of 6.125% senior notes due July 2023 (the “2023 Notes” and collectively with the 2025 Notes and the 2027 Notes, the “Senior Notes”). Of the aggregate $650.0 million of 2023 Notes, $350.0 million were issued at par and $300.0 million were issued at 99.375% of par. The 2023 Notes were issued under an indenture dated July 8, 2015, the terms of which are generally consistent with the 2020 Indenture. Interest on the 2023 Notes is payable semi-annually in arrears on January 15 and July 15 of each year. As of September 26, 2020 and December 28, 2019, the Company was in compliance with all financial covenants under the applicable indentures. Senior Secured Credit Facilities — Summit LLC has credit facilities that provide for term loans in an aggregate amount of $650.0 million and revolving credit commitments in an aggregate amount of $345.0 million (the “Senior Secured Credit Facilities”). Under the Senior Secured Credit Facilities, required principal repayments of 0.25% of the refinanced aggregate amount of term debt are due on the last business day of each March, June, September and December commencing with the March 2018 payment. The unpaid principal balance is due in full on the maturity date, which is November 21, 2024. On February 25, 2019, Summit LLC entered into Incremental Amendment No. 4 to the credit agreement governing the Senior Secured Credit Facilities (the “Credit Agreement”) which, among other things, increased the total amount available under the revolving credit facility to $345.0 million and extended the maturity date of the Credit Agreement with respect to the revolving credit commitments to February 25, 2024. The revolving credit facility bears interest per annum equal to, at Summit LLC’s option, either (i) a base rate determined by reference to the highest of (a) the federal funds rate plus 0.50%, (b) the prime rate of Bank of America, N.A. and (c) LIBOR plus 1.00%, plus an applicable margin of 2.00% for base rate loans or (ii) a LIBOR rate determined by reference to Reuters prior to the interest period relevant to such borrowing adjusted for certain additional costs plus an applicable margin of 3.00% for LIBOR rate loans. There were no outstanding borrowings under the revolving credit facility as of September 26, 2020 and December 28, 2019, with borrowing capacity of $329.1 million remaining as of September 26, 2020, which is net of $15.9 million of outstanding letters of credit. The outstanding letters of credit are renewed annually and support required bonding on construction projects, large leases, workers compensation claims and the Company’s insurance liabilities. Summit LLC’s Consolidated First Lien Net Leverage Ratio, as such term is defined in the Credit Agreement, should be no greater than 4.75:1.0 as of each quarter-end. As of September 26, 2020 and December 28, 2019, Summit LLC was in compliance with all financial covenants. Summit LLC’s wholly-owned domestic subsidiary companies, subject to certain exclusions and exceptions, are named as subsidiary guarantors of the Senior Notes and the Senior Secured Credit Facilities. In addition, Summit LLC has pledged substantially all of its assets as collateral, subject to certain exclusions and exceptions, for the Senior Secured Credit Facilities. The following table presents the activity for the deferred financing fees for the nine months ended September 26, 2020 and September 28, 2019: Deferred financing fees Balance—December 28, 2019 $ 15,436 Loan origination fees 9,565 Amortization (2,499) Write off of deferred financing fees (3,338) Balance—September 26, 2020 $ 19,164 Balance—December 29, 2018 $ 15,475 Loan origination fees 6,312 Amortization (2,668) Write off of deferred financing fees (2,851) Balance—September 28, 2019 $ 16,268 Other —On January 15, 2015, the Company’s wholly-owned subsidiary in British Columbia, Canada entered into an agreement with HSBC Bank Canada for a (i) $6.0 million Canadian dollar (“CAD”) revolving credit commitment to be used for operating activities that bears interest per annum equal to the bank’s prime rate plus 0.20%, (ii) $0.5 million CAD revolving credit commitment to be used for capital equipment that bears interest per annum at the bank’s prime rate plus 0.90% and (iii) $0.3 million CAD revolving credit commitment to provide guarantees on behalf of that subsidiary. There were no amounts outstanding under this agreement as of September 26, 2020 or December 28, 2019.
Summit Materials, LLC
Debt Instrument [Line Items]
DEBT	DEBT Debt consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Term Loan, due 2024: $619.5 million and $624.3 million, net of $0.9 million and $1.1 million discount at September 26, 2020 and December 28, 2019, respectively $ 618,545 $ 623,140 6 1/8 % Senior Notes, due 2023: $650.0 million, net of $0.9 million discount at December 28, 2019 — 649,133 5 1/8 % Senior Notes, due 2025 300,000 300,000 6 1/2 % Senior Notes, due 2027 300,000 300,000 5 1/4 % Senior Notes, due 2029 700,000 — Total 1,918,545 1,872,273 Current portion of long-term debt 7,942 7,942 Long-term debt $ 1,910,603 $ 1,864,331 The contractual payments of long-term debt, including current maturities, for the five years subsequent to September 26, 2020, are as follows: 2020 (three months) $ 3,177 2021 6,353 2022 6,354 2023 6,354 2024 597,253 2025 300,000 Thereafter 1,000,000 Total 1,919,491 Less: Original issue net discount (946) Less: Capitalized loan costs (17,391) Total debt $ 1,901,154 Senior Notes —On August 11, 2020, Summit LLC and Summit Finance (together, the “Issuers”) issued $700.0 million in aggregate principal amount of 5.250% senior notes due January 15, 2029 (the “2029 Notes”). The 2029 Notes were issued at 100.0% of their par value with proceeds of $690.4 million, net of related fees and expenses. The 2029 Notes were issued under an indenture dated August 11, 2020 (the "2020 Indenture"). The 2020 Indenture contains covenants limiting, among other things, Summit LLC and its restricted subsidiaries’ ability to incur additional indebtedness or issue certain preferred shares, pay dividends, redeem stock or make other distributions, make certain investments, sell or transfer certain assets, create liens, consolidate, merge, sell or otherwise dispose of all or substantially all of its assets, enter into certain transactions with affiliates, and designate subsidiaries as unrestricted subsidiaries. The 2020 Indenture also contains customary events of default. Interest on the 2029 Notes is payable semi-annually on January 15 and July 15 of each year commencing on January 15, 2021. In August 2020, using the proceeds from the 2029 Notes, all of the outstanding $650.0 million 6.125% senior notes due 2023 (the “2023 Notes”) were redeemed at a price equal to par and the indenture under which the 2023 Notes were issued was satisfied and discharged. As a result of the extinguishment, charges of $4.1 million were recognized in the quarter ended September 26, 2020, which included charges of $0.8 million for the write-off of original issue discount and $3.3 million for the write-off of deferred financing fees. On March 15, 2019, the Issuers issued $300.0 million in aggregate principal amount of 6.500% senior notes due March 15, 2027 (the “2027 Notes”). The 2027 Notes were issued at 100.0% of their par value with proceeds of $296.3 million, net of related fees and expenses. The 2027 Notes were issued under an indenture dated March 25, 2019, the terms of which are generally consistent with the 2020 Indenture. Interest on the 2027 Notes is payable semi-annually on March 15 and September 15 of each year commencing on September 15, 2019. In March 2019, using the proceeds from the 2027 Notes, all of the outstanding $250.0 million 8.500% senior notes due 2022 (the “2022 Notes”) were redeemed at a price equal to par plus an applicable premium and the indenture under which the 2022 Notes were issued was satisfied and discharged. As a result of the extinguishment, charges of $14.6 million were recognized in the quarter ended March 30, 2019, which included charges of$11.7 million for the applicable redemption premium and $2.9 million for the write-off of deferred financing fees. In 2017, the Issuers issued $300.0 million of 5.125% senior notes due June 1, 2025 (the “2025 Notes”). The 2025 Notes were issued at 100.0% of their par value with proceeds of $295.4 million, net of related fees and expenses. The 2025 Notes were issued under an indenture dated June 1, 2017, the terms of which are generally consistent with the 2020 Indenture. Interest on the 2025 Notes is payable semi-annually on June 1 and December 1 of each year commencing on December 1, 2017. In 2015, the Issuers issued $650.0 million of 6.125% senior notes due July 2023 (the “2023 Notes” and collectively with the 2025 Notes and the 2027 Notes, the “Senior Notes”). Of the aggregate $650.0 million of 2023 Notes, $350.0 million were issued at par and $300.0 million were issued at 99.375% of par. The 2023 Notes were issued under an indenture dated July 8, 2015, the terms of which are generally consistent with the 2020 Indenture. Interest on the 2023 Notes is payable semi-annually in arrears on January 15 and July 15 of each year. As of September 26, 2020 and December 28, 2019, the Company was in compliance with all financial covenants under the applicable indentures. Senior Secured Credit Facilities — Summit LLC has credit facilities that provide for term loans in an aggregate amount of $650.0 million and revolving credit commitments in an aggregate amount of $345.0 million (the “Senior Secured Credit Facilities”). Under the Senior Secured Credit Facilities, required principal repayments of 0.25% of the refinanced aggregate amount of term debt are due on the last business day of each March, June, September and December commencing with the March 2018 payment. The unpaid principal balance is due in full on the maturity date, which is November 21, 2024. On February 25, 2019, Summit LLC entered into Incremental Amendment No. 4 to the credit agreement governing the Senior Secured Credit Facilities (the “Credit Agreement”) which, among other things, increased the total amount available under the revolving credit facility to $345.0 million and extended the maturity date of the Credit Agreement with respect to the revolving credit commitments to February 25, 2024. The revolving credit facility bears interest per annum equal to, at Summit LLC’s option, either (i) a base rate determined by reference to the highest of (a) the federal funds rate plus 0.50%, (b) the prime rate of Bank of America, N.A. and (c) LIBOR plus 1.00%, plus an applicable margin of 2.00% for base rate loans or (ii) a LIBOR rate determined by reference to Reuters prior to the interest period relevant to such borrowing adjusted for certain additional costs plus an applicable margin of 3.00% for LIBOR rate loans. There were no outstanding borrowings under the revolving credit facility as of September 26, 2020 and December 28, 2019, with borrowing capacity of $329.1 million remaining as of September 26, 2020, which is net of $15.9 million of outstanding letters of credit. The outstanding letters of credit are renewed annually and support required bonding on construction projects, large leases, workers compensation claims and the Company’s insurance liabilities. Summit LLC’s Consolidated First Lien Net Leverage Ratio, as such term is defined in the Credit Agreement, should be no greater than 4.75:1.0 as of each quarter-end. As of September 26, 2020 and December 28, 2019, Summit LLC was in compliance with all financial covenants. Summit LLC’s wholly-owned domestic subsidiary companies, subject to certain exclusions and exceptions, are named as subsidiary guarantors of the Senior Notes and the Senior Secured Credit Facilities. In addition, Summit LLC has pledged substantially all of its assets as collateral, subject to certain exclusions and exceptions, for the Senior Secured Credit Facilities. The following table presents the activity for the deferred financing fees for the nine months ended September 26, 2020 and September 28, 2019: Deferred financing fees Balance—December 28, 2019 $ 15,436 Loan origination fees 9,565 Amortization (2,499) Write off of deferred financing fees (3,338) Balance—September 26, 2020 $ 19,164 Balance - December 29, 2018 $ 15,475 Loan origination fees 6,312 Amortization (2,668) Write off of deferred financing fees (2,851) Balance - September 28, 2019 $ 16,268 Other —On January 15, 2015, the Company’s wholly-owned subsidiary in British Columbia, Canada entered into an agreement with HSBC Bank Canada for a (i) $6.0 million Canadian dollar (“CAD”) revolving credit commitment to be used for operating activities that bears interest per annum equal to the bank’s prime rate plus 0.20%, (ii) $0.5 million CAD revolving credit commitment to be used for capital equipment that bears interest per annum at the bank’s prime rate plus 0.90% and (iii) $0.3 million CAD revolving credit commitment to provide guarantees on behalf of that subsidiary. There were no amounts outstanding under this agreement as of September 26, 2020 or December 28, 2019.

INCOME TAXES

INCOME TAXES	9 Months Ended
	Sep. 26, 2020
Income Taxes [Line Items]
INCOME TAXES	INCOME TAXES Summit Inc.’s tax provision includes its proportional share of Summit Holdings’ tax attributes. Summit Holdings’ subsidiaries are primarily limited liability companies but do include certain entities organized as C corporations and a Canadian subsidiary. The tax attributes related to the limited liability companies are passed on to Summit Holdings and then to its partners, including Summit Inc. The tax attributes associated with the C corporation and Canadian subsidiaries are fully reflected in the Company’s accounts. Our income tax benefit was $(19.6) million and $(25.3) million in the three and nine months ended September 26, 2020, respectively, and our income tax expense was $45.6 million and $34.3 million in the three and nine months ended September 28, 2019, respectively. The effective tax rate for Summit Inc. differs from the federal rate primarily due to (1) unrecognized tax benefits, (2) state taxes, (3) tax depletion expense in excess of the expense recorded under U.S. GAAP, (4) the minority interest in the Summit Holdings partnership that is allocated outside of the Company and (5) various other items such as limitations on meals and entertainment, certain stock compensation and other costs. In the first quarter of 2020, we recorded the impact of the Coronavirus Aid, Relief and Economic Stability Act ("CARES Act") enacted into law in late March 2020, which reduced our unrecognized tax benefits by approximately $9.5 million. In the third quarter of 2020, final regulations were issued clarifying portions of the Tax Cuts and Jobs Act of 2017 ("TCJA"). Under the provisions of the final regulations, we reversed our unrecognized tax benefits of $32.9 million in the third quarter 2020. As of September 26, 2020 and December 28, 2019, Summit Inc. had a valuation allowance of $1.7 million, which relates to certain deferred tax assets in taxable entities where realization is not more likely than not. No material interest or penalties were recognized in income tax expense during the three and nine months ended September 26, 2020 and September 28, 2019. Tax Receivable Agreement —The Company is party to a TRA with certain current and former holders of LP Units that provides for the payment by Summit Inc. to exchanging holders of LP Units of 85% of the benefits, if any, that Summit Inc. actually realizes (or, under certain circumstances such as an early termination of the TRA, is deemed to realize) as a result of increases in the tax basis of tangible and intangible assets of Summit Holdings and certain other tax benefits related to entering into the TRA, including tax benefits attributable to payments under the TRA. In the nine months ended September 26, 2020, 196,542 LP Units were acquired by Summit Inc. in exchange for an equal number of newly-issued shares of Summit Inc.’s Class A common stock. These exchanges resulted in net new deferred tax assets of approximately $1.2 million. As we determined that the deferred tax assets created from these exchanges are realizable and payment under the TRA is considered probable, we have recorded 85% of the increase in deferred tax assets as TRA liability and the remainder as an adjustment to additional paid in capital. As of September 26, 2020 and December 28, 2019, we had recorded $328.0 million and $327.0 million of TRA liability, respectively. Tax Distributions – The holders of Summit Holdings’ LP Units, including Summit Inc., incur U.S. federal, state and local income taxes on their share of any taxable income of Summit Holdings. The limited partnership agreement of Summit Holdings provides for pro rata cash distributions (“tax distributions”) to the holders of the LP Units in an amount generally calculated to provide each holder of LP Units with sufficient cash to cover its tax liability in respect of the LP Units. In general, these tax distributions are computed based on Summit Holdings’ estimated taxable income allocated to Summit Inc. multiplied by an assumed tax rate equal to the highest effective marginal combined U.S. federal, state and local income tax rate in New York, New York. Summit Holdings did not make any tax distributions in the nine months ended September 26, 2020 and September 28, 2019.
Summit Materials, LLC
Income Taxes [Line Items]
INCOME TAXES	INCOME TAXES Summit LLC is a limited liability company and passes its tax attributes for federal and state tax purposes to its parent company and is generally not subject to federal or state income tax. However, certain subsidiary entities file federal, state and Canadian income tax returns due to their status as taxable entities in the respective jurisdiction. The effective income tax rate for the C Corporations differs from the statutory federal rate primarily due to (1) tax depletion expense in excess of the expense recorded under U.S. GAAP, (2) state income taxes and the effect of graduated tax rates and (3) various other items, such as limitations on meals and entertainment and other costs. The effective income tax rate for the Canadian subsidiary is not significantly different from its historical effective tax rate. Summit LLC and its subsidiaries expect additional unrecognized tax benefits related to the deductibility of interest expense in 2020 and 2019 that if recognized would affect the annual effective tax rate, and included that in its estimate of those amounts in its annual effective tax rate. We did not recognize interest or penalties related to this amount as it is offset by other attributes. No material interest or penalties were recognized in income tax expense during the three and nine months ended September 26, 2020 and September 28, 2019. We recognized uncertain tax benefits in the three and nine months ended September 26, 2020 related to the passage of the Coronavirus Aid, Relief and Economic Stability Act (“CARES Act”) on March 25, 2020.

EARNINGS PER SHARE

EARNINGS PER SHARE	9 Months Ended
	Sep. 26, 2020
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE Basic earnings per share is computed by dividing net earnings by the weighted average common shares outstanding and diluted net earnings is computed by dividing net earnings, adjusted for changes in the earnings allocated to Summit Inc. as a result of the assumed conversion of LP Units, by the weighted-average common shares outstanding assuming dilution. The following table shows the calculation of basic and diluted earnings per share: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Net income attributable to Summit Inc. $ 90,730 $ 55,757 $ 102,815 $ 23,395 Weighted average shares of Class A stock outstanding Add: Nonvested restricted stock awards of retirement eligible shares 320,343 — 145,155 — Add: Weighted average shares of Class A stock outstanding 114,116,564 112,179,137 113,943,292 112,020,275 Weighted average basic shares outstanding 114,436,907 112,179,137 114,088,447 112,020,275 Basic earnings per share $ 0.79 $ 0.50 $ 0.90 $ 0.21 Diluted net income attributable to Summit Inc. $ 90,730 $ 55,757 $ 102,815 $ 23,395 Weighted average shares of Class A stock outstanding 114,116,564 112,179,137 113,943,292 112,020,275 Add: weighted average of LP Units — — — — Add: stock options — 2,788,221 — 216,165 Add: warrants — 100,037 — — Add: restricted stock units 263,886 384,571 450,353 222,533 Add: performance stock units 91,721 53,156 63,631 38,637 Weighted average dilutive shares outstanding 114,472,171 115,505,122 114,457,276 112,497,610 Diluted earnings per share $ 0.79 $ 0.48 $ 0.90 $ 0.21 Excluded from the above calculations were the shares noted below as they were antidilutive: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Antidilutive shares: LP Units 3,053,115 3,368,058 3,086,819 3,404,231 Time-vesting stock options 2,095,929 — 2,095,929 — Warrants 100,037 — 100,037 100,037

STOCKHOLDERS' EQUITY_MEMBERS' I

STOCKHOLDERS' EQUITY/MEMBERS' INTEREST	9 Months Ended
	Sep. 26, 2020
Schedule of Capitalization, Equity [Line Items]
STOCKHOLDERS' EQUITY	STOCKHOLDERS’ EQUITY During 2020 and 2019, certain limited partners of Summit Holdings exchanged their LP Units for shares of Class A common stock of Summit Inc. The following table summarizes the changes in our ownership of Summit Holdings: Summit Inc. LP Units Total Summit Inc. Balance — December 28, 2019 113,309,385 3,249,657 116,559,042 97.2 % Exchanges during period 196,542 (196,542) — Stock option exercises 14,404 — 14,404 Other equity transactions 603,580 — 603,580 Balance — September 26, 2020 114,123,911 3,053,115 117,177,026 97.4 % Balance — December 29, 2018 111,658,927 3,435,518 115,094,445 97.0 % Exchanges during period 107,336 (107,336) — Other equity transactions 509,735 — 509,735 Balance — September 28, 2019 112,275,998 3,328,182 115,604,180 97.1 % Summit Inc. is Summit Holdings’ primary beneficiary and thus consolidates Summit Holdings in its consolidated financial statements with a corresponding noncontrolling interest reclassification, which was 2.6% and 2.8% as of September 26, 2020 and December 28, 2019, respectively. Accumulated other comprehensive income (loss) —The changes in each component of accumulated other comprehensive income (loss) consisted of the following: Change in Foreign currency Cash flow hedge Accumulated Balance — December 28, 2019 $ 2,171 $ 1,277 $ — $ 3,448 Foreign currency translation adjustment, net of tax — (2,473) — (2,473) Balance — September 26, 2020 $ 2,171 $ (1,196) $ — $ 975 Balance — December 29, 2018 $ 3,573 $ (2,147) $ 1,255 $ 2,681 Foreign currency translation adjustment, net of tax — 2,364 — 2,364 Loss on cash flow hedges, net of tax — — (107) (107) Balance — September 28, 2019 $ 3,573 $ 217 $ 1,148 $ 4,938
Summit Materials, LLC
Schedule of Capitalization, Equity [Line Items]
MEMBERS' INTEREST	MEMBERS’ INTEREST Accumulated other comprehensive income (loss) —The changes in each component of accumulated other comprehensive income (loss) consisted of the following: Accumulated Foreign currency other Change in translation Cash flow hedge comprehensive retirement plans adjustments adjustments (loss) income Balance — December 28, 2019 $ (6,317) $ (14,654) $ — $ (20,971) Foreign currency translation adjustment — (3,395) — (3,395) Balance — September 26, 2020 $ (6,317) $ (18,049) $ — $ (24,366) Balance — December 29, 2018 $ (4,392) $ (19,370) $ 146 $ (23,616) Foreign currency translation adjustment — 3,263 — 3,263 Loss on cash flow hedges — — (148) (148) Balance — September 28, 2019 $ (4,392) $ (16,107) $ (2) $ (20,501)

SUPPLEMENTAL CASH FLOW INFORMAT

SUPPLEMENTAL CASH FLOW INFORMATION	9 Months Ended
	Sep. 26, 2020
Schedule Of Cash Flow Supplemental [Line Items]
SUPPLEMENTAL CASH FLOW INFORMATION	SUPPLEMENTAL CASH FLOW INFORMATION Supplemental cash flow information is as follows: Nine months ended September 26, 2020 September 28, 2019 Cash payments: Interest $ 86,427 $ 89,759 Payments (refunds) for income taxes, net 1,131 (912) Operating cash payments on operating leases 8,372 8,188 Operating cash payments on finance leases 2,402 2,322 Finance cash payments on finance leases 11,528 9,806 Non cash financing activities: Right of use assets obtained in exchange for operating lease obligations $ 2,931 $ 4,387 Right of use assets obtained in exchange for finance leases obligations 17,605 18,586 Exchange of LP Units to shares of Class A common stock 4,648 1,995
Summit Materials, LLC
Schedule Of Cash Flow Supplemental [Line Items]
SUPPLEMENTAL CASH FLOW INFORMATION	SUPPLEMENTAL CASH FLOW INFORMATION Supplemental cash flow information is as follows: Nine months ended September 26, 2020 September 28, 2019 Cash payments: Interest $ 86,427 $ 89,759 Payments (refunds) for income taxes, net 1,131 (912) Operating cash payments on operating leases 8,372 8,188 Operating cash payments on finance leases 2,402 2,322 Finance cash payments on finance leases 11,528 9,806 Non cash financing activities: Right of use assets obtained in exchange for operating lease obligations $ 2,931 $ 4,387 Right of use assets obtained in exchange for finance leases obligations 17,605 18,586

LEASES

LEASES	9 Months Ended
	Sep. 26, 2020
Lessee, Lease, Description [Line Items]
LEASES	LEASES We lease construction and office equipment, distribution facilities and office space. Leases with an initial term of 12 months or less, including month to month leases, are not recorded on the balance sheet. Lease expense for short-term leases is recognized on a straight line basis over the lease term. For lease agreements entered into or reassessed after the adoption of Topic 842, we combine lease and nonlease components. While we also own mineral leases for mining operations, those leases are outside the scope of Topic 842. Assets acquired under finance leases are included in property, plant and equipment. Many of our leases include options to purchase the leased equipment. The depreciable life of assets and leasehold improvements are limited by the expected lease term, unless there is a transfer of title or purchase option reasonably certain of exercise. Our lease agreements do not contain any material residual value guarantees or material restrictive covenants. The components of lease expense were as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Operating lease cost $ 2,478 $ 2,608 $ 7,576 $ 7,757 Variable lease cost 90 151 253 366 Short-term lease cost 14,335 11,871 33,369 28,043 Financing lease cost: Amortization of right-of-use assets 3,439 2,612 9,307 7,905 Interest on lease liabilities 780 773 2,329 2,404 Total lease cost $ 21,122 $ 18,015 $ 52,834 $ 46,475 September 26, 2020 December 28, 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 28,551 $ 32,777 Current operating lease liabilities $ 8,193 $ 8,427 Noncurrent operating lease liabilities 21,327 25,381 Total operating lease liabilities $ 29,520 $ 33,808 Finance leases: Property and equipment, gross $ 92,873 $ 82,660 Less accumulated depreciation (29,663) (24,907) Property and equipment, net $ 63,210 $ 57,753 Current finance lease liabilities $ 24,868 $ 16,007 Long-term finance lease liabilities 34,913 40,410 Total finance lease liabilities $ 59,781 $ 56,417 Weighted average remaining lease term (years): Operating leases 9.0 8.6 Finance lease 2.6 2.6 Weighted average discount rate (%): Operating leases 5.4 % 5.5 % Finance lease 5.2 % 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 (three months) $ 2,444 $ 4,995 2021 8,818 26,169 2022 5,475 18,519 2023 4,243 6,867 2024 2,547 3,207 2025 1,507 2,573 Thereafter 12,808 2,831 Total lease payments 37,842 65,161 Less imputed interest (8,322) (5,380) Present value of lease payments $ 29,520 $ 59,781
LEASES	LEASES We lease construction and office equipment, distribution facilities and office space. Leases with an initial term of 12 months or less, including month to month leases, are not recorded on the balance sheet. Lease expense for short-term leases is recognized on a straight line basis over the lease term. For lease agreements entered into or reassessed after the adoption of Topic 842, we combine lease and nonlease components. While we also own mineral leases for mining operations, those leases are outside the scope of Topic 842. Assets acquired under finance leases are included in property, plant and equipment. Many of our leases include options to purchase the leased equipment. The depreciable life of assets and leasehold improvements are limited by the expected lease term, unless there is a transfer of title or purchase option reasonably certain of exercise. Our lease agreements do not contain any material residual value guarantees or material restrictive covenants. The components of lease expense were as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Operating lease cost $ 2,478 $ 2,608 $ 7,576 $ 7,757 Variable lease cost 90 151 253 366 Short-term lease cost 14,335 11,871 33,369 28,043 Financing lease cost: Amortization of right-of-use assets 3,439 2,612 9,307 7,905 Interest on lease liabilities 780 773 2,329 2,404 Total lease cost $ 21,122 $ 18,015 $ 52,834 $ 46,475 September 26, 2020 December 28, 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 28,551 $ 32,777 Current operating lease liabilities $ 8,193 $ 8,427 Noncurrent operating lease liabilities 21,327 25,381 Total operating lease liabilities $ 29,520 $ 33,808 Finance leases: Property and equipment, gross $ 92,873 $ 82,660 Less accumulated depreciation (29,663) (24,907) Property and equipment, net $ 63,210 $ 57,753 Current finance lease liabilities $ 24,868 $ 16,007 Long-term finance lease liabilities 34,913 40,410 Total finance lease liabilities $ 59,781 $ 56,417 Weighted average remaining lease term (years): Operating leases 9.0 8.6 Finance lease 2.6 2.6 Weighted average discount rate (%): Operating leases 5.4 % 5.5 % Finance lease 5.2 % 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 (three months) $ 2,444 $ 4,995 2021 8,818 26,169 2022 5,475 18,519 2023 4,243 6,867 2024 2,547 3,207 2025 1,507 2,573 Thereafter 12,808 2,831 Total lease payments 37,842 65,161 Less imputed interest (8,322) (5,380) Present value of lease payments $ 29,520 $ 59,781
Summit Materials, LLC
Lessee, Lease, Description [Line Items]
LEASES	LEASES We lease construction and office equipment, distribution facilities and office space. Leases with an initial term of 12 months or less, including month to month leases, are not recorded on the balance sheet. Lease expense for short-term leases is recognized on a straight line basis over the lease term. For lease agreements entered into or reassessed after the adoption of Topic 842, we combine lease and nonlease components. While we also own mineral leases for mining operations, those leases are outside the scope of Topic 842. Assets acquired under finance leases are included in property, plant and equipment. Many of our leases include options to purchase the leased equipment. The depreciable life of assets and leasehold improvements are limited by the expected lease term, unless there is a transfer of title or purchase option reasonably certain of exercise. Our lease agreements do not contain any material residual value guarantees or material restrictive covenants. The components of lease expense were as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Operating lease cost $ 2,478 $ 2,608 $ 7,576 $ 7,757 Variable lease cost 90 151 253 366 Short-term lease cost 14,335 11,871 33,369 28,043 Financing lease cost: Amortization of right-of-use assets 3,439 2,612 9,307 7,905 Interest on lease liabilities 780 773 2,329 2,404 Total lease cost $ 21,122 $ 18,015 $ 52,834 $ 46,475 September 26, 2020 December 28, 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 28,551 $ 32,777 Current operating lease liabilities $ 8,193 $ 8,427 Noncurrent operating lease liabilities 21,327 25,381 Total operating lease liabilities $ 29,520 $ 33,808 Finance leases: Property and equipment, gross $ 92,873 $ 82,660 Less accumulated depreciation (29,663) (24,907) Property and equipment, net $ 63,210 $ 57,753 Current finance lease liabilities $ 24,868 $ 16,007 Long-term finance lease liabilities 34,913 40,410 Total finance lease liabilities $ 59,781 $ 56,417 Weighted average remaining lease term (years): Operating leases 9.0 8.6 Finance lease 2.6 2.6 Weighted average discount rate (%): Operating leases 5.4 % 5.5 % Finance lease 5.2 % 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 (three months) $ 2,444 $ 4,995 2021 8,818 26,169 2022 5,475 18,519 2023 4,243 6,867 2024 2,547 3,207 2025 1,507 2,573 Thereafter 12,808 2,831 Total lease payments 37,842 65,161 Less imputed interest (8,322) (5,380) Present value of lease payments $ 29,520 $ 59,781
LEASES	LEASES We lease construction and office equipment, distribution facilities and office space. Leases with an initial term of 12 months or less, including month to month leases, are not recorded on the balance sheet. Lease expense for short-term leases is recognized on a straight line basis over the lease term. For lease agreements entered into or reassessed after the adoption of Topic 842, we combine lease and nonlease components. While we also own mineral leases for mining operations, those leases are outside the scope of Topic 842. Assets acquired under finance leases are included in property, plant and equipment. Many of our leases include options to purchase the leased equipment. The depreciable life of assets and leasehold improvements are limited by the expected lease term, unless there is a transfer of title or purchase option reasonably certain of exercise. Our lease agreements do not contain any material residual value guarantees or material restrictive covenants. The components of lease expense were as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Operating lease cost $ 2,478 $ 2,608 $ 7,576 $ 7,757 Variable lease cost 90 151 253 366 Short-term lease cost 14,335 11,871 33,369 28,043 Financing lease cost: Amortization of right-of-use assets 3,439 2,612 9,307 7,905 Interest on lease liabilities 780 773 2,329 2,404 Total lease cost $ 21,122 $ 18,015 $ 52,834 $ 46,475 September 26, 2020 December 28, 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 28,551 $ 32,777 Current operating lease liabilities $ 8,193 $ 8,427 Noncurrent operating lease liabilities 21,327 25,381 Total operating lease liabilities $ 29,520 $ 33,808 Finance leases: Property and equipment, gross $ 92,873 $ 82,660 Less accumulated depreciation (29,663) (24,907) Property and equipment, net $ 63,210 $ 57,753 Current finance lease liabilities $ 24,868 $ 16,007 Long-term finance lease liabilities 34,913 40,410 Total finance lease liabilities $ 59,781 $ 56,417 Weighted average remaining lease term (years): Operating leases 9.0 8.6 Finance lease 2.6 2.6 Weighted average discount rate (%): Operating leases 5.4 % 5.5 % Finance lease 5.2 % 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 (three months) $ 2,444 $ 4,995 2021 8,818 26,169 2022 5,475 18,519 2023 4,243 6,867 2024 2,547 3,207 2025 1,507 2,573 Thereafter 12,808 2,831 Total lease payments 37,842 65,161 Less imputed interest (8,322) (5,380) Present value of lease payments $ 29,520 $ 59,781

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 26, 2020
Loss Contingencies [Line Items]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES The Company is party to certain legal actions arising from the ordinary course of business activities. Accruals are recorded when the outcome is probable and can be reasonably estimated. While the ultimate results of claims and litigation cannot be predicted with certainty, management expects that the ultimate resolution of all current pending or threatened claims and litigation will not have a material effect on the Company’s consolidated financial position, results of operations or liquidity. The Company records legal fees as incurred. In March 2018, we were notified of an investigation by the Canadian Competition Bureau (the “CCB”) into pricing practices by certain asphalt paving contractors in British Columbia, including Winvan Paving, Ltd. (“Winvan”). We believe the investigation is focused on time periods prior to our April 2017 acquisition of Winvan and we are cooperating with the CCB. Although we currently do not believe this matter will have a material adverse effect on our business, financial condition or results of operations, we are currently not able to predict the ultimate outcome or cost of the investigation. Environmental Remediation and Site Restoration —The Company’s operations are subject to and affected by federal, state, provincial and local laws and regulations relating to the environment, health and safety and other regulatory matters. These operations require environmental operating permits, which are subject to modification, renewal and revocation. The Company regularly monitors and reviews its operations, procedures and policies for compliance with these laws and regulations. Despite these compliance efforts, risk of environmental liability is inherent in the operation of the Company’s business, as it is with other companies engaged in similar businesses and there can be no assurance that environmental liabilities or noncompliance will not have a material adverse effect on the Company’s consolidated financial condition, results of operations or liquidity. The Company has asset retirement obligations arising from regulatory and contractual requirements to perform reclamation activities at the time certain quarries and landfills are closed. As of September 26, 2020 and December 28, 2019, $33.2 million and $28.8 million, respectively, were included in other noncurrent liabilities on the consolidated balance sheets and $6.9 million and $7.9 million, respectively, were included in accrued expenses for future reclamation costs. The total undiscounted anticipated costs for site reclamation as of September 26, 2020 and December 28, 2019 were $106.9 million and $97.4 million, respectively. Other —The Company is obligated under various firm purchase commitments for certain raw materials and services that are in the ordinary course of business. Management does not expect any significant changes in the market value of these goods and services during the commitment period that would have a material adverse effect on the financial condition, results of operations and cash flows of the Company. The terms of the purchase commitments generally approximate one year.
Summit Materials, LLC
Loss Contingencies [Line Items]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES The Company is party to certain legal actions arising from the ordinary course of business activities. Accruals are recorded when the outcome is probable and can be reasonably estimated. While the ultimate results of claims and litigation cannot be predicted with certainty, management expects that the ultimate resolution of all current pending or threatened claims and litigation will not have a material effect on the Company’s consolidated financial position, results of operations or liquidity. The Company records legal fees as incurred. In March 2018, we were notified of an investigation by the Canadian Competition Bureau (the “CCB”) into pricing practices by certain asphalt paving contractors in British Columbia, including Winvan Paving, Ltd. (“Winvan”). We believe the investigation is focused on time periods prior to our April 2017 acquisition of Winvan and we are cooperating with the CCB. Although we currently do not believe this matter will have a material adverse effect on our business, financial condition or results of operations, we are currently not able to predict the ultimate outcome or cost of the investigation. Environmental Remediation and Site Restoration —The Company’s operations are subject to and affected by federal, state, provincial and local laws and regulations relating to the environment, health and safety and other regulatory matters. These operations require environmental operating permits, which are subject to modification, renewal and revocation. The Company regularly monitors and reviews its operations, procedures and policies for compliance with these laws and regulations. Despite these compliance efforts, risk of environmental liability is inherent in the operation of the Company’s business, as it is with other companies engaged in similar businesses and there can be no assurance that environmental liabilities or noncompliance will not have a material adverse effect on the Company’s consolidated financial condition, results of operations or liquidity. The Company has asset retirement obligations arising from regulatory and contractual requirements to perform reclamation activities at the time certain quarries and landfills are closed. As of September 26, 2020 and December 28, 2019, $33.2 million and $28.8 million, respectively, were included in other noncurrent liabilities on the consolidated balance sheets and $6.9 million and $7.9 million, respectively, were included in accrued expenses for future reclamation costs. The total undiscounted anticipated costs for site reclamation as of September 26, 2020 and December 28, 2019 were $106.9 million and $97.4 million, respectively. Other —The Company is obligated under various firm purchase commitments for certain raw materials and services that are in the ordinary course of business. Management does not expect any significant changes in the market value of these goods and services during the commitment period that would have a material adverse effect on the financial condition, results of operations and cash flows of the Company. The terms of the purchase commitments generally approximate one year.

FAIR VALUE

FAIR VALUE	9 Months Ended
	Sep. 26, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
FAIR VALUE	FAIR VALUE Fair Value Measurements— Certain acquisitions made by the Company require the payment of contingent amounts of purchase consideration. These payments are contingent on specified operating results being achieved in periods subsequent to the acquisition and will only be made if earn-out thresholds are achieved. Contingent consideration obligations are measured at fair value each reporting period. Any adjustments to fair value are recognized in earnings in the period identified. The fair value of contingent consideration as of September 26, 2020 and December 28, 2019 was: September 26, 2020 December 28, 2019 Current portion of acquisition-related liabilities and Accrued expenses: Contingent consideration $ 525 $ 1,967 Acquisition-related liabilities and Other noncurrent liabilities: Contingent consideration $ 1,303 $ 1,302 The fair value of contingent consideration was based on unobservable, or Level 3, inputs, including projected probability-weighted cash payments and a 9.5% discount rate, which reflects a market discount rate. Changes in fair value may occur as a result of a change in actual or projected cash payments, the probability weightings applied by the Company to projected payments or a change in the discount rate. Significant increases or decreases in any of these inputs in isolation could result in a lower, or higher, fair value measurement. There were no material valuation adjustments to contingent consideration as of September 26, 2020 and September 28, 2019. Financial Instruments —The Company’s financial instruments include debt and certain acquisition-related liabilities (deferred consideration and noncompete obligations). The carrying value and fair value of these financial instruments as of September 26, 2020 and December 28, 2019 was: September 26, 2020 December 28, 2019 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt(1) $ 1,939,247 $ 1,918,545 $ 1,918,720 $ 1,872,273 Level 3 Current portion of deferred consideration and noncompete obligations(2) 31,443 31,443 30,733 30,733 Long term portion of deferred consideration and noncompete obligations(3) 11,573 11,573 18,499 18,499 (1) $7.9 million was included in current portion of debt as of September 26, 2020 and December 28, 2019. (2) Included in current portion of acquisition-related liabilities on the consolidated balance sheets. (3) Included in acquisition-related liabilities on the consolidated balance sheets. The fair value of debt was determined based on observable, or Level 2, inputs, such as interest rates, bond yields and quoted prices in inactive markets. The fair values of the deferred consideration and noncompete obligations were determined based on unobservable, or Level 3, inputs, including the cash payment terms in the purchase agreements and a discount rate reflecting the Company’s credit risk. The discount rate used is generally consistent with that used when the obligations were initially recorded. Securities with a maturity of three months or less are considered cash equivalents and the fair value of these assets approximates their carrying value.
Summit Materials, LLC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
FAIR VALUE	FAIR VALUE Fair Value Measurements— Certain acquisitions made by the Company require the payment of contingent amounts of purchase consideration. These payments are contingent on specified operating results being achieved in periods subsequent to the acquisition and will only be made if earn-out thresholds are achieved. Contingent consideration obligations are measured at fair value each reporting period. Any adjustments to fair value are recognized in earnings in the period identified. The fair value of contingent consideration as of September 26, 2020 and December 28, 2019 was: September 26, 2020 December 28, 2019 Current portion of acquisition-related liabilities and Accrued expenses: Contingent consideration $ 525 $ 1,967 Acquisition-related liabilities and Other noncurrent liabilities: Contingent consideration $ 1,303 $ 1,302 The fair value of contingent consideration was based on unobservable, or Level 3, inputs, including projected probability-weighted cash payments and a 9.5% discount rate, which reflects a market discount rate. Changes in fair value may occur as a result of a change in actual or projected cash payments, the probability weightings applied by the Company to projected payments or a change in the discount rate. Significant increases or decreases in any of these inputs in isolation could result in a lower, or higher, fair value measurement. There were no material valuation adjustments to contingent consideration as of September 26, 2020 and September 28, 2019. Financial Instruments —The Company’s financial instruments include debt and certain acquisition-related liabilities (deferred consideration and noncompete obligations). The carrying value and fair value of these financial instruments as of September 26, 2020 and December 28, 2019 was: September 26, 2020 December 28, 2019 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt(1) $ 1,939,247 $ 1,918,545 $ 1,918,720 $ 1,872,273 Level 3 Current portion of deferred consideration and noncompete obligations(2) 29,067 29,067 28,233 28,233 Long term portion of deferred consideration and noncompete obligations(3) 11,573 11,573 16,364 16,364 (1) $7.9 million was included in current portion of debt as of September 26, 2020 and December 28, 2019. (2) Included in current portion of acquisition-related liabilities on the consolidated balance sheets. (3) Included in acquisition-related liabilities on the consolidated balance sheets. The fair value of debt was determined based on observable, or Level 2, inputs, such as interest rates, bond yields and quoted prices in inactive markets. The fair values of the deferred consideration and noncompete obligations were determined based on unobservable, or Level 3, inputs, including the cash payment terms in the purchase agreements and a discount rate reflecting the Company’s credit risk. The discount rate used is generally consistent with that used when the obligations were initially recorded. Securities with a maturity of three months or less are considered cash equivalents and the fair value of these assets approximates their carrying value.

SEGMENT INFORMATION

SEGMENT INFORMATION	9 Months Ended
	Sep. 26, 2020
Segment Reporting Information [Line Items]
SEGMENT INFORMATION	SEGMENT INFORMATION The Company has three operating segments: West, East and Cement, which are its reporting segments. These segments are consistent with the Company’s management reporting structure. The operating results of each segment are regularly reviewed and evaluated by the Chief Executive Officer, our Company’s Chief Operating Decision Maker (“CODM”). The CODM primarily evaluates the performance of the Company’s segments and allocates resources to them based on a segment profit metric that we call Adjusted EBITDA, which is computed as earnings from operations before interest, taxes, depreciation, depletion, amortization, accretion, share-based compensation, and transaction costs, as well as various other non-recurring, non-cash amounts. The West and East segments have several acquired subsidiaries that are engaged in various activities including quarry mining, aggregate production and contracting. The Cement segment is engaged in the production of Portland cement. Assets employed by each segment include assets directly identified with those operations. Corporate assets consist primarily of cash, property, plant and equipment for corporate operations and other assets not directly identifiable with a reportable business segment. The accounting policies applicable to each segment are consistent with those used in the consolidated financial statements. The following tables display selected financial data for the Company’s reportable business segments as of September 26, 2020 and December 28, 2019 and for the three and nine months ended September 26, 2020 and September 28, 2019: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Revenue*: West $ 390,310 $ 366,504 $ 919,016 $ 848,661 East 234,435 266,587 590,341 596,107 Cement 84,874 98,991 198,461 220,844 Total revenue $ 709,619 $ 732,082 $ 1,707,818 $ 1,665,612 *Intercompany sales are immaterial and the presentation above only reflects sales to external customers. Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Income from operations before taxes $ 73,156 $ 103,839 $ 79,597 $ 58,998 Interest expense 24,623 28,917 78,049 88,423 Depreciation, depletion and amortization 57,364 54,575 161,912 162,417 Accretion 690 552 1,848 1,723 Loss on debt financings 4,064 — 4,064 14,565 Transaction costs 445 751 1,517 1,449 Non-cash compensation 13,322 4,819 23,119 15,424 Other 4,083 (136) 4,287 (2,628) Total Adjusted EBITDA $ 177,747 $ 193,317 $ 354,393 $ 340,371 Total Adjusted EBITDA by Segment: West $ 95,470 $ 81,936 $ 196,881 $ 151,054 East 56,943 76,825 119,900 134,479 Cement 35,086 42,683 63,172 75,537 Corporate and other (9,752) (8,127) (25,560) (20,699) Total Adjusted EBITDA $ 177,747 $ 193,317 $ 354,393 $ 340,371 Nine months ended September 26, 2020 September 28, 2019 Purchases of property, plant and equipment West $ 51,148 $ 61,679 East 75,006 61,830 Cement 12,097 15,087 Total reportable segments 138,251 138,596 Corporate and other 1,755 1,166 Total purchases of property, plant and equipment $ 140,006 $ 139,762 Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Depreciation, depletion, amortization and accretion: West $ 23,117 $ 23,307 $ 67,082 $ 70,156 East 22,803 19,668 65,293 59,719 Cement 11,155 11,111 28,425 31,280 Total reportable segments 57,075 54,086 160,800 161,155 Corporate and other 979 1,041 2,960 2,985 Total depreciation, depletion, amortization and accretion $ 58,054 $ 55,127 $ 163,760 $ 164,140 September 26, 2020 December 28, 2019 Total assets: West $ 1,540,792 $ 1,379,684 East 1,347,883 1,288,835 Cement 868,458 868,528 Total reportable segments 3,757,133 3,537,047 Corporate and other 535,037 530,509 Total $ 4,292,170 $ 4,067,556
Summit Materials, LLC
Segment Reporting Information [Line Items]
SEGMENT INFORMATION	SEGMENT INFORMATION The Company has three operating segments: West, East and Cement, which are its reporting segments. These segments are consistent with the Company’s management reporting structure. The operating results of each segment are regularly reviewed and evaluated by the Chief Executive Officer, our Company’s Chief Operating Decision Maker (“CODM”). The CODM primarily evaluates the performance of the Company’s segments and allocates resources to them based on a segment profit metric that we call Adjusted EBITDA, which is computed as earnings from operations before interest, taxes, depreciation, depletion, amortization, accretion, share-based compensation, and transaction costs, as well as various other non-recurring, non-cash amounts. The West and East segments have several acquired subsidiaries that are engaged in various activities including quarry mining, aggregate production and contracting. The Cement segment is engaged in the production of Portland cement. Assets employed by each segment include assets directly identified with those operations. Corporate assets consist primarily of cash, property, plant and equipment for corporate operations and other assets not directly identifiable with a reportable business segment. The accounting policies applicable to each segment are consistent with those used in the consolidated financial statements. The following tables display selected financial data for the Company’s reportable business segments as of September 26, 2020 and December 28, 2019 and for the three and nine months ended September 26, 2020 and September 28, 2019: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Revenue*: West $ 390,310 $ 366,504 $ 919,016 $ 848,661 East 234,435 266,587 590,341 596,107 Cement 84,874 98,991 198,461 220,844 Total revenue $ 709,619 $ 732,082 $ 1,707,818 $ 1,665,612 *Intercompany sales are immaterial and the presentation above only reflects sales to external customers. Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Income from operations before taxes $ 73,218 $ 103,956 $ 79,839 $ 59,401 Interest expense 24,561 28,800 77,807 88,020 Depreciation, depletion and amortization 57,364 54,575 161,912 162,417 Accretion 690 552 1,848 1,723 Loss on debt financings 4,064 — 4,064 14,565 Transaction costs 445 751 1,517 1,449 Non-cash compensation 13,322 4,819 23,119 15,424 Other 4,083 (136) 4,287 (2,628) Total Adjusted EBITDA $ 177,747 $ 193,317 $ 354,393 $ 340,371 Total Adjusted EBITDA by Segment: West $ 95,470 $ 81,936 $ 196,881 $ 151,054 East 56,943 76,825 119,900 134,479 Cement 35,086 42,683 63,172 75,537 Corporate and other (9,752) (8,127) (25,560) (20,699) Total Adjusted EBITDA $ 177,747 $ 193,317 $ 354,393 $ 340,371 Nine months ended September 26, 2020 September 28, 2019 Purchases of property, plant and equipment West $ 51,148 $ 61,679 East 75,006 61,830 Cement 12,097 15,087 Total reportable segments 138,251 138,596 Corporate and other 1,755 1,166 Total purchases of property, plant and equipment $ 140,006 $ 139,762 Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Depreciation, depletion, amortization and accretion: West $ 23,117 $ 23,307 $ 67,082 $ 70,156 East 22,803 19,668 65,293 59,719 Cement 11,155 11,111 28,425 31,280 Total reportable segments 57,075 54,086 160,800 161,155 Corporate and other 979 1,041 2,960 2,985 Total depreciation, depletion, amortization and accretion $ 58,054 $ 55,127 $ 163,760 $ 164,140 September 26, 2020 December 28, 2019 Total assets: West $ 1,540,792 $ 1,379,684 East 1,347,883 1,288,835 Cement 868,458 868,528 Total reportable segments 3,757,133 3,537,047 Corporate and other 294,137 319,176 Total $ 4,051,270 $ 3,856,223

GUARANTOR AND NON-GUARANTOR FIN

GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION	9 Months Ended
	Sep. 26, 2020
Summit Materials, LLC
Guarantor and Non-Guarantor Financial Information	GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION Summit LLC’s domestic wholly-owned subsidiary companies other than Finance Corp. are named as guarantors (collectively, the “Guarantors”) of the Senior Notes. Finance Corp. does not and will not have any assets or operations other than as may be incidental to its activities as a co-issuer of the Senior Notes and other indebtedness. Certain other partially-owned subsidiaries and a non-U.S. entity do not guarantee the Senior Notes (collectively, the “Non-Guarantors”). The Guarantors provide a joint and several, full and unconditional guarantee of the Senior Notes. There are no significant restrictions on Summit LLC’s ability to obtain funds from any of the Guarantor Subsidiaries in the form of dividends or loans. Additionally, there are no significant restrictions on a Guarantor Subsidiary’s ability to obtain funds from Summit LLC or its direct or indirect subsidiaries. The following condensed consolidating balance sheets, statements of operations and cash flows are provided for the Issuers, the wholly-owned guarantors and the Non-Guarantors. Earnings from subsidiaries are included in other income in the condensed consolidated statements of operations below. The financial information may not necessarily be indicative of the financial position, results of operations or cash flows had the guarantor or non-guarantor subsidiaries operated as independent entities. Condensed Consolidating Balance Sheets September 26, 2020 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Assets Current assets: Cash and cash equivalents $ 277,052 $ 3,350 $ 12,943 $ (4,588) $ 288,757 Accounts receivable, net 1 289,977 19,486 (87) 309,377 Intercompany receivables 424,533 1,128,619 — (1,553,152) — Cost and estimated earnings in excess of billings — 40,711 3,290 — 44,001 Inventories — 203,217 6,557 — 209,774 Other current assets 2,219 9,724 1,689 — 13,632 Total current assets 703,805 1,675,598 43,965 (1,557,827) 865,541 Property, plant and equipment, net 10,383 1,691,382 61,301 — 1,763,066 Goodwill — 1,222,786 81,300 — 1,304,086 Intangible assets, net — 37,923 — — 37,923 Operating lease right-of-use assets 2,793 21,647 4,111 — 28,551 Other assets 3,922,503 197,286 671 (4,068,357) 52,103 Total assets $ 4,639,484 $ 4,846,622 $ 191,348 $ (5,626,184) $ 4,051,270 Liabilities and Member’s Interest Current liabilities: Current portion of debt $ 7,942 $ — $ — $ — $ 7,942 Current portion of acquisition-related liabilities — 29,592 — — 29,592 Accounts payable 5,935 135,658 8,580 (87) 150,086 Accrued expenses 37,693 105,201 5,989 (4,588) 144,295 Current operating lease liabilities 874 6,239 1,080 — 8,193 Intercompany payables 1,072,127 469,880 11,145 (1,553,152) — Billings in excess of costs and estimated earnings — 13,139 1,086 — 14,225 Total current liabilities 1,124,571 759,709 27,880 (1,557,827) 354,333 Long-term debt 1,893,212 — — — 1,893,212 Acquisition-related liabilities — 12,876 — — 12,876 Noncurrent operating lease liabilities 2,801 15,600 2,926 — 21,327 Other noncurrent liabilities 4,389 207,881 107,162 (164,421) 155,011 Total liabilities 3,024,973 996,066 137,968 (1,722,248) 2,436,759 Total member's interest 1,614,511 3,850,556 53,380 (3,903,936) 1,614,511 Total liabilities and member’s interest $ 4,639,484 $ 4,846,622 $ 191,348 $ (5,626,184) $ 4,051,270 Condensed Consolidating Balance Sheets December 28, 2019 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Assets Current assets: Cash and cash equivalents $ 302,474 $ 5,488 $ 9,834 $ (6,477) $ 311,319 Accounts receivable, net — 234,053 19,236 (33) 253,256 Intercompany receivables 443,323 942,385 — (1,385,708) — Cost and estimated earnings in excess of billings — 12,291 797 — 13,088 Inventories — 199,794 4,993 — 204,787 Other current assets 1,763 10,308 1,760 — 13,831 Total current assets 747,560 1,404,319 36,620 (1,392,218) 796,281 Property, plant and equipment, net 11,602 1,674,443 61,404 — 1,747,449 Goodwill — 1,142,063 58,636 — 1,200,699 Intangible assets, net — 23,498 — — 23,498 Operating lease right-of-use assets 3,316 24,551 4,910 — 32,777 Other assets 3,596,161 168,314 734 (3,709,690) 55,519 Total assets $ 4,358,639 $ 4,437,188 $ 162,304 $ (5,101,908) $ 3,856,223 Liabilities and Member’s Interest Current liabilities: Current portion of debt $ 7,942 $ — $ — $ — $ 7,942 Current portion of acquisition-related liabilities — 30,200 — — 30,200 Accounts payable 4,588 103,812 8,603 (33) 116,970 Accrued expenses 51,043 72,970 2,701 (6,477) 120,237 Current operating lease liabilities 764 6,571 1,092 — 8,427 Intercompany payables 922,356 447,827 15,525 (1,385,708) — Billings in excess of costs and estimated earnings — 12,183 1,681 — 13,864 Total current liabilities 986,693 673,563 29,602 (1,392,218) 297,640 Long-term debt 1,851,057 — — — 1,851,057 Acquisition-related liabilities — 17,666 — — 17,666 Noncurrent operating lease liabilities 3,480 18,047 3,854 — 25,381 Other noncurrent liabilities 4,259 203,919 80,169 (137,018) 151,329 Total liabilities 2,845,489 913,195 113,625 (1,529,236) 2,343,073 Total member's interest 1,513,150 3,523,993 48,679 (3,572,672) 1,513,150 Total liabilities and member’s interest $ 4,358,639 $ 4,437,188 $ 162,304 $ (5,101,908) $ 3,856,223 Condensed Consolidating Statements of Operations For the three months ended September 26, 2020 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 689,842 $ 23,780 $ (4,003) $ 709,619 Cost of revenue (excluding items shown separately below) — 458,028 14,979 (4,003) 469,004 General and administrative expenses 23,955 55,242 2,747 — 81,944 Depreciation, depletion, amortization and accretion 980 55,542 1,532 — 58,054 Operating (loss) income (24,935) 121,030 4,522 — 100,617 Other (income) loss, net (134,672) (889) (276) 138,675 2,838 Interest expense (income) 31,170 (7,990) 1,381 — 24,561 Income from operation before taxes 78,567 129,909 3,417 (138,675) 73,218 Income tax expense (benefit) 243 (6,286) 937 — (5,106) Net income attributable to Summit LLC $ 78,324 $ 136,195 $ 2,480 $ (138,675) $ 78,324 Comprehensive income attributable to member of Summit Materials, LLC $ 80,342 $ 136,195 $ 462 $ (136,657) $ 80,342 Condensed Consolidating Statements of Operations For the nine months ended September 26, 2020 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 1,659,526 $ 61,556 $ (13,264) $ 1,707,818 Cost of revenue (excluding items shown separately below) — 1,138,689 39,892 (13,264) 1,165,317 General and administrative expenses 50,964 160,670 8,150 — 219,784 Depreciation, depletion, amortization and accretion 2,960 156,697 4,103 — 163,760 Operating (loss) income (53,924) 203,470 9,411 — 158,957 Other (income) loss, net (235,001) (1,733) 271 237,774 1,311 Interest expense (income) 95,379 (21,352) 3,780 — 77,807 Income from operation before taxes 85,698 226,555 5,360 (237,774) 79,839 Income tax expense (benefit) 982 (7,383) 1,524 — (4,877) Net income attributable to Summit LLC $ 84,716 $ 233,938 $ 3,836 $ (237,774) $ 84,716 Comprehensive income attributable to member of Summit Materials, LLC $ 81,321 $ 233,938 $ 7,231 $ (241,169) $ 81,321 Condensed Consolidating Statements of Operations For the three months ended September 28, 2019 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 706,999 $ 29,186 $ (4,103) $ 732,082 Cost of revenue (excluding items shown separately below) — 467,595 19,487 (4,103) 482,979 General and administrative expenses 13,603 46,816 2,676 — 63,095 Depreciation, depletion, amortization and accretion 1,042 52,739 1,346 — 55,127 Operating (loss) income (14,645) 139,849 5,677 — 130,881 Other (income) loss, net (132,261) (1,501) 222 131,665 (1,875) Interest expense (income) 32,129 (4,532) 1,203 — 28,800 Income from operation before taxes 85,487 145,882 4,252 (131,665) 103,956 Income tax expense 288 17,325 1,144 — 18,757 Net income attributable to Summit LLC $ 85,199 $ 128,557 $ 3,108 $ (131,665) $ 85,199 Comprehensive income attributable to member of Summit Materials, LLC $ 84,026 $ 128,402 $ 4,436 $ (132,838) $ 84,026 Condensed Consolidating Statements of Operations For the nine months ended September 28, 2019 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 1,603,338 $ 70,321 $ (8,047) $ 1,665,612 Cost of revenue (excluding items shown separately below) — 1,114,401 49,122 (8,047) 1,155,476 General and administrative expenses 37,887 146,136 8,341 — 192,364 Depreciation, depletion, amortization and accretion 2,986 156,827 4,327 — 164,140 Operating (loss) income (40,873) 185,974 8,531 — 153,632 Other (income) loss, net (183,971) (6,427) (553) 197,162 6,211 Interest expense (income) 94,848 (10,443) 3,615 — 88,020 Income from operation before taxes 48,250 202,844 5,469 (197,162) 59,401 Income tax expense 1,114 9,673 1,478 — 12,265 Net income attributable to Summit LLC $ 47,136 $ 193,171 $ 3,991 $ (197,162) $ 47,136 Comprehensive income attributable to member of Summit Materials, LLC $ 50,251 $ 193,319 $ 728 $ (194,047) $ 50,251 Condensed Consolidating Statements of Cash Flows For the nine months ended September 26, 2020 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Net cash (used in) provided by operating activities $ (110,054) $ 288,198 $ 39,895 $ — $ 218,039 Cash flow from investing activities: Acquisitions, net of cash acquired — (92,085) (31,110) — (123,195) Purchase of property, plant and equipment (1,755) (136,670) (1,581) — (140,006) Proceeds from the sale of property, plant, and equipment — 8,708 140 — 8,848 Other — 1,395 — — 1,395 Net cash used for investing activities (1,755) (218,652) (32,551) — (252,958) Cash flow from financing activities: Proceeds from investment by member (91,856) 87,925 4,260 — 329 Net proceeds from debt issuance 700,000 — — — 700,000 Loans received from and payments made on loans from other Summit Companies 145,896 (139,650) (8,135) 1,889 — Payments on long-term debt (654,765) (11,983) (144) — (666,892) Payments on acquisition-related liabilities — (7,891) — — (7,891) Debt issuance costs (9,565) — — — (9,565) Distributions from partnership (2,500) — — — (2,500) Other (823) (85) — — (908) Net cash provided by (used in) financing activities 86,387 (71,684) (4,019) 1,889 12,573 Impact of cash on foreign currency — — (216) — (216) Net (decrease) increase in cash (25,422) (2,138) 3,109 1,889 (22,562) Cash — Beginning of period 302,474 5,488 9,834 (6,477) 311,319 Cash — End of period $ 277,052 $ 3,350 $ 12,943 $ (4,588) $ 288,757 Condensed Consolidating Statements of Cash Flows For the nine months ended September 28, 2019 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Net cash (used in) provided by operating activities $ (85,516) $ 241,172 $ 8,187 $ — $ 163,843 Cash flow from investing activities: Acquisitions, net of cash acquired — (2,842) — — (2,842) Purchase of property, plant and equipment (1,166) (129,170) (9,426) — (139,762) Proceeds from the sale of property, plant, and equipment — 12,950 85 — 13,035 Other — (207) — — (207) Net cash used for investing activities (1,166) (119,269) (9,341) — (129,776) Cash flow from financing activities: Proceeds from investment by member (35,581) 38,140 — — 2,559 Net proceeds from debt issuance 300,000 — — — 300,000 Loans received from and payments made on loans from other Summit Companies 147,325 (147,782) 506 (49) — Payments on long-term debt (254,765) (9,965) (176) — (264,906) Payments on acquisition-related liabilities — (8,500) — — (8,500) Financing costs (6,312) — — — (6,312) Distributions from partnership (2,500) — — — (2,500) Other (462) (39) — — (501) Net cash provided by (used in) financing activities 147,705 (128,146) 330 (49) 19,840 Impact of cash on foreign currency — — 174 — 174 Net increase (decrease) in cash 61,023 (6,243) (650) (49) 54,081 Cash — Beginning of period 117,219 8,440 7,719 (4,870) 128,508 Cash — End of period $ 178,242 $ 2,197 $ 7,069 $ (4,919) $ 182,589

SUMMARY OF ORGANIZATION AND S_2

SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES - (Policies)	9 Months Ended
	Sep. 26, 2020
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Basis of Presentation	Basis of Presentation —These unaudited consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures typically included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. These unaudited consolidated financial statements should be read in conjunction with the Company's audited consolidated financial statements and the notes thereto as of and for the year ended December 28, 2019. The Company continues to follow the accounting policies set forth in those audited consolidated financial statements. Management believes that these consolidated interim financial statements include all adjustments, normal and recurring in nature, that are necessary to present fairly the financial position of the Company as of September 26, 2020, the results of operations for the three and nine months ended September 26, 2020 and September 28, 2019 and cash flows for the nine months ended September 26, 2020 and September 28, 2019.
Principles of Consolidation	Principles of Consolidation —The consolidated financial statements include the accounts of Summit Inc. and its majority owned subsidiaries. All intercompany balances and transactions have been eliminated. For a summary of the changes in Summit Inc.’s ownership of Summit Holdings, see Note 9, Stockholders’ Equity.
Use of Estimates	Use of Estimates —Preparation of these consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities and reported amounts of revenue and expenses. Such estimates include the valuation of accounts receivable, inventories, valuation of deferred tax assets, goodwill, intangibles and other long-lived assets, tax receivable agreement ("TRA") liability, pension and other postretirement obligations and asset retirement obligations. Estimates also include revenue earned on contracts and costs to complete contracts. Most of the Company’s paving and related services are performed under fixed unit-price contracts with state and local governmental entities. Management regularly evaluates its estimates and assumptions based on historical experience and other factors, including the current economic environment. As future events and their effects cannot be determined with precision, actual results can differ significantly from estimates made. Changes in estimates, including
Business and Credit Concentrations	Business and Credit Concentrations— The Company’s operations are conducted primarily across 23 U.S. states and in British Columbia, Canada, with the most significant revenue generated in Texas, Kansas, Utah and Missouri. The Company’s accounts receivable consist primarily of amounts due from customers within these areas. Therefore, collection of these accounts is dependent on the economic conditions in the aforementioned states, as well as specific situations affecting individual customers. Credit granted within the Company’s trade areas has been granted to many customers, and management does not believe that a significant concentration of credit exists with respect to any individual customer or group of customers. No single customer accounted for more than 10% of the Company’s total revenue in the three and nine months ended September 26, 2020 or September 28, 2019.
Revenue Recognition	Revenue Recognition— We earn revenue from the sale of products, which primarily include aggregates, cement, ready-mix concrete and asphalt, but also include concrete products, and from the provision of services, which are primarily paving and related services. Products: Revenue for product sales is recognized when evidence of an arrangement exists and when control passes, which generally is when the product is shipped. Services: We earn revenue from the provision of services, which are primarily paving and related services, which are typically calculated using monthly progress based on the percentage of completion or a customer’s engineer review of progress. The majority of our construction service contracts are completed within one year, but may occasionally extend beyond this time frame. The majority of our construction service contracts are for work that occurs mostly during the spring, summer and fall. We generally measure progress toward completion on long-term paving and related services contracts based on the proportion of costs incurred to date relative to total estimated costs at completion.
Earnings per Share	Earnings per Share— The Company computes basic earnings per share attributable to stockholders by dividing income attributable to Summit Inc. by the weighted-average shares of Class A common stock outstanding. Diluted earnings per share reflects the potential dilution beyond shares for basic earnings per share that could occur if securities or other contracts to issue common stock were exercised, converted into common stock, or resulted in the issuance of common stock that would have shared in the Company’s earnings. Since the Class B common stock has no economic value, those shares are not included in the weighted-average common share amount for basic or diluted earnings per share. In addition, as the shares of Class A common stock are issued by Summit Inc., the earnings and equity interests of noncontrolling interests are not included in basic earnings per share.
Tax Receivable Agreement	Tax Receivable Agreement —When Class A limited partnership units of Summit Holdings (“LP Units”) are exchanged for shares of Class A common stock of Summit Inc. or Summit Inc. purchases LP Units for cash, this results in increases in Summit Inc.’s share of the tax basis of the tangible and intangible assets, which increases the tax depreciation and amortization deductions that otherwise would not have been available to Summit Inc. These increases in tax basis and tax depreciation and amortization deductions are expected to reduce the amount of cash taxes that we would otherwise be required to pay in the future. Prior to our initial public offering (“IPO”), we entered into a TRA with the pre-IPO owners that requires us to pay the pre-IPO owners or their permitted assignees 85% of the amount of cash savings, if any, in U.S. federal, state, and local income tax that we actually realize as a result of these exchanges. These benefits include (1) increases in the tax basis of tangible and intangible assets of Summit Holdings and certain other tax benefits related to entering into the TRA, (2) tax benefits attributable to payments under the TRA, or (3) under certain circumstances such as an early termination of the TRA, we are deemed to realize, as a result of the increases in tax basis in connection with exchanges by the pre-IPO owners described above and certain other tax benefits attributable to payments under the TRA. We periodically evaluate the realizability of the deferred tax assets resulting from the exchange of LP Units for Class A common stock. If the deferred tax assets are determined to be realizable, we then assess whether payment of amounts under the TRA have become probable. If so, we record a TRA liability equal to 85% of such deferred tax assets, and the remaining 15% as an increase to additional paid-in capital. If a deferred tax asset subject to the TRA is determined not to be realizable and therefore subject to a valuation allowance, we do not record a TRA liability for such deferred tax assets. In subsequent periods, we assess the realizability of all of our deferred tax assets subject to the TRA. Should we determine a deferred tax asset with a valuation allowance is realizable in a subsequent period, the related valuation allowance will be released and consideration of a corresponding TRA liability will be assessed. The realizability of deferred tax assets, including those subject to the TRA, is dependent upon the generation of future taxable income during the periods in which those deferred tax assets become deductible and consideration of prudent and feasible tax-planning strategies. The measurement of the TRA liability is accounted for as a contingent liability. Therefore, once we determine that a payment to a pre-IPO owner has become probable and can be estimated, the estimate of payment will be accrued.
New Accounting Standards	New Accounting Standards — In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which reduces the accounting complexity of implementing a cloud computing service arrangement. The ASU aligns the capitalization of implementation costs among hosting arrangements and costs incurred to develop internal-use software. We adopted this ASU in the first quarter of 2020 and the adoption of this ASU did not have a material impact on the consolidated financial statements.
Leases	We lease construction and office equipment, distribution facilities and office space. Leases with an initial term of 12 months or less, including month to month leases, are not recorded on the balance sheet. Lease expense for short-term leases is recognized on a straight line basis over the lease term. For lease agreements entered into or reassessed after the adoption of Topic 842, we combine lease and nonlease components. While we also own mineral leases for mining operations, those leases are outside the scope of Topic 842. Assets acquired under finance leases are included in property, plant and equipment.Many of our leases include options to purchase the leased equipment. The depreciable life of assets and leasehold improvements are limited by the expected lease term, unless there is a transfer of title or purchase option reasonably certain of exercise. Our lease agreements do not contain any material residual value guarantees or material restrictive covenants.
Summit Materials, LLC
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Basis of Presentation	Basis of Presentation —These unaudited consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures typically included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. These unaudited consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto as of and for the year ended December 28, 2019. The Company continues to follow the accounting policies set forth in those audited consolidated financial statements. Management believes that these consolidated interim financial statements include all adjustments, normal and recurring in nature, that are necessary to present fairly the financial position of the Company as of September 26, 2020, the results of operations for the three and nine months ended September 26, 2020 and September 28, 2019 and cash flows for the nine months ended September 26, 2020 and September 28, 2019.
Use of Estimates	Use of Estimates —Preparation of these consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities and reported amounts of revenue and expenses. Such estimates include the valuation of accounts receivable, inventories, valuation of deferred tax assets, goodwill, intangibles and other long-lived assets, pension and other postretirement obligations and asset retirement obligations. Estimates also include revenue earned on contracts and costs to complete contracts. Most of the Company’s paving and related services are performed under fixed unit-price contracts with state and local governmental entities. Management regularly evaluates its estimates and assumptions based on historical experience and other factors, including the current economic environment. As future events and their effects cannot be determined with precision, actual results can differ significantly from estimates made. Changes in estimates, including those resulting from continuing changes in the economic environment, are reflected in the Company’s consolidated financial statements when the change in estimate occurs.
Business and Credit Concentrations	Business and Credit Concentrations— The Company’s operations are conducted primarily across 23 U.S. states and in British Columbia, Canada, with the most significant revenue generated in Texas, Kansas, Utah and Missouri. The Company’s accounts receivable consist primarily of amounts due from customers within these areas. Therefore, collection of these accounts is dependent on the economic conditions in the aforementioned states, as well as specific situations affecting individual customers. Credit granted within the Company’s trade areas has been granted to many customers, and management does not believe that a significant concentration of credit exists with respect to any individual customer or group of customers. No single customer accounted for more than 10% of the Company’s total revenue in the three and nine months ended September 26, 2020 or September 28, 2019.
Revenue Recognition	Revenue Recognition— We earn revenue from the sale of products, which primarily include aggregates, cement, ready-mix concrete and asphalt, but also include concrete products, and from the provision of services, which are primarily paving and related services. Products: Revenue for product sales is recognized when evidence of an arrangement exists and when control passes, which generally is when the product is shipped. Services: We earn revenue from the provision of services, which are primarily paving and related services, which are typically calculated using monthly progress based on the percentage of completion or a customer’s engineer review of progress. The majority of our construction service contracts are completed within one year, but may occasionally extend beyond this time frame. The majority of our construction service contracts are for work that occurs mostly during the spring, summer and fall. We generally measure progress toward completion on long-term paving and related services contracts based on the proportion of costs incurred to date relative to total estimated costs at completion. The percentage of completion method of accounting involves the use of various estimating techniques to project costs at completion, and in some cases includes estimates of recoveries asserted against the customer for changes in specifications or other disputes.
New Accounting Standards	New Accounting Standards— In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which reduces the accounting complexity of implementing a cloud computing service arrangement. The ASU aligns the capitalization of implementation costs among hosting arrangements and costs incurred to develop internal-use software. We adopted this ASU in the first quarter of 2020 and the adoption of this ASU did not have a material impact on the consolidated financial statements.

ACQUISITIONS, GOODWILL AND IN_2

ACQUISITIONS, GOODWILL AND INTANGIBLES - (Tables)	9 Months Ended
	Sep. 26, 2020
Business Acquisition [Line Items]
Summary of Number of Business Acquisitions by Segment	Nine months ended Year ended September 26, 2020 December 28, 2019 West 2 2 East 1 —
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table summarizes aggregated information regarding the fair values of the assets acquired and liabilities assumed as of the respective acquisition dates: Nine months ended Year ended September 26, 2020 December 28, 2019 Financial assets $ 8,866 $ — Inventories 2,328 52 Property, plant and equipment 17,069 3,542 Other assets 758 — Financial liabilities (3,980) (36) Other long-term liabilities (6,473) — Net assets acquired 18,568 3,558 Goodwill 105,280 1,834 Purchase price 123,848 5,392 Other (652) — Net cash paid for acquisitions $ 123,196 $ 5,392
Goodwill by Reportable Segment and in Total	Changes in the carrying amount of goodwill, by reportable segment, from December 28, 2019 to September 26, 2020 are summarized as follows: West East Cement Total Balance—December 28, 2019 $ 584,617 $ 410,426 $ 204,656 $ 1,199,699 Acquisitions (1) 105,298 — — 105,298 Foreign currency translation adjustments (1,911) — — (1,911) Balance—September 26, 2020 $ 688,004 $ 410,426 $ 204,656 $ 1,303,086 _______________________________________________________________________
Intangible Assets by Type and in Total	The following table shows intangible assets by type and in total: September 26, 2020 December 28, 2019 Gross Accumulated Net Gross Accumulated Net Operating permits $ 23,345 $ (1,162) $ 22,183 $ 6,609 $ (290) $ 6,319 Mineral leases 19,225 (7,286) 11,939 19,064 (6,408) 12,656 Reserve rights 6,234 (2,444) 3,790 6,234 (2,248) 3,986 Trade names 1,000 (1,000) — 1,000 (958) 42 Other 586 (575) 11 957 (462) 495 Total intangible assets $ 50,390 $ (12,467) $ 37,923 $ 33,864 $ (10,366) $ 23,498
Estimated Amortization Expense for Intangible Assets	The estimated amortization expense for the intangible assets for each of the five years subsequent to September 26, 2020 is as follows: 2020 (three months) $ 686 2021 2,719 2022 2,723 2023 2,590 2024 2,495 2025 2,450 Thereafter 24,260 Total $ 37,923
Summit Materials, LLC
Business Acquisition [Line Items]
Summary of Number of Business Acquisitions by Segment	The following table summarizes the Company’s acquisitions by region and period: Nine months ended Year ended September 26, 2020 December 28, 2019 West 2 2 East 1 —
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table summarizes aggregated information regarding the fair values of the assets acquired and liabilities assumed as of the respective acquisition dates: Nine months ended Year ended September 26, 2020 December 28, 2019 Financial assets $ 8,866 $ — Inventories 2,328 52 Property, plant and equipment 17,069 3,542 Other assets 758 — Financial liabilities (3,980) (36) Other long-term liabilities (6,473) — Net assets acquired 18,568 3,558 Goodwill 105,280 1,834 Purchase price 123,848 5,392 Other (652) — Net cash paid for acquisitions $ 123,196 $ 5,392
Goodwill by Reportable Segment and in Total	Changes in the carrying amount of goodwill, by reportable segment, from December 28, 2019 to September 26, 2020 are summarized as follows: West East Cement Total Balance—December 28, 2019 $ 585,617 $ 410,426 $ 204,656 $ 1,200,699 Acquisitions (1) 105,298 — — 105,298 Foreign currency translation adjustments (1,911) — — (1,911) Balance—September 26, 2020 $ 689,004 $ 410,426 $ 204,656 $ 1,304,086 _______________________________________________________________________ (1) Reflects goodwill from acquisitions completed during the nine months ended September 26, 2020 and working capital adjustments from prior year acquisitions.
Intangible Assets by Type and in Total	The following table shows intangible assets by type and in total: September 26, 2020 December 28, 2019 Gross Accumulated Net Gross Accumulated Net Operating permits $ 23,345 $ (1,162) $ 22,183 $ 6,609 $ (290) $ 6,319 Mineral leases 19,225 (7,286) 11,939 19,064 (6,408) 12,656 Reserve rights 6,234 (2,444) 3,790 6,234 (2,248) 3,986 Trade names 1,000 (1,000) — 1,000 (958) 42 Other 586 (575) 11 957 (462) 495 Total intangible assets $ 50,390 $ (12,467) $ 37,923 $ 33,864 $ (10,366) $ 23,498
Estimated Amortization Expense for Intangible Assets	The estimated amortization expense for the intangible assets for each of the five years subsequent to September 26, 2020 is as follows: 2020 (three months) $ 686 2021 2,719 2022 2,723 2023 2,590 2024 2,495 2025 2,450 Thereafter 24,260 Total $ 37,923

REVENUE RECOGNITION - (Tables)

REVENUE RECOGNITION - (Tables)	9 Months Ended
	Sep. 26, 2020
Revenue from External Customer [Line Items]
Revenue by Product	Revenue by product for the three and nine months ended September 26, 2020 and September 28, 2019 is as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Revenue by product*: Aggregates $ 136,396 $ 137,528 $ 362,546 $ 354,050 Cement 82,698 92,482 188,854 202,780 Ready-mix concrete 179,124 172,758 488,710 444,258 Asphalt 128,125 137,753 255,992 254,156 Paving and related services 136,191 138,083 280,446 267,732 Other 47,085 53,478 131,270 142,636 Total revenue $ 709,619 $ 732,082 $ 1,707,818 $ 1,665,612 *Revenue from liquid asphalt terminals is included in asphalt revenue.
Summary of Accounts Receivable, Net	Accounts receivable, net consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Trade accounts receivable $ 231,663 $ 191,672 Construction contract receivables 62,183 47,966 Retention receivables 18,501 17,808 Receivables from related parties 1,918 1,596 Accounts receivable 314,265 259,042 Less: Allowance for doubtful accounts (4,888) (5,786) Accounts receivable, net $ 309,377 $ 253,256
Summit Materials, LLC
Revenue from External Customer [Line Items]
Revenue by Product	Revenue by product for the three and nine months ended September 26, 2020 and September 28, 2019 is as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Revenue by product*: Aggregates $ 136,396 $ 137,528 $ 362,546 $ 354,050 Cement 82,698 92,482 188,854 202,780 Ready-mix concrete 179,124 172,758 488,710 444,258 Asphalt 128,125 137,753 255,992 254,156 Paving and related services 136,191 138,083 280,446 267,732 Other 47,085 53,478 131,270 142,636 Total revenue $ 709,619 $ 732,082 $ 1,707,818 $ 1,665,612 *Revenue from liquid asphalt terminals is included in asphalt revenue.
Summary of Accounts Receivable, Net	Accounts receivable, net consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Trade accounts receivable $ 231,663 $ 191,672 Construction contract receivables 62,183 47,966 Retention receivables 18,501 17,808 Receivables from related parties 1,918 1,596 Accounts receivable 314,265 259,042 Less: Allowance for doubtful accounts (4,888) (5,786) Accounts receivable, net $ 309,377 $ 253,256

INVENTORIES - (Tables)

INVENTORIES - (Tables)	9 Months Ended
	Sep. 26, 2020
Inventory [Line Items]
Components of Inventories	Inventories consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Aggregate stockpiles $ 143,271 $ 140,461 Finished goods 31,657 33,023 Work in process 10,062 7,664 Raw materials 24,784 23,639 Total $ 209,774 $ 204,787
Summit Materials, LLC
Inventory [Line Items]
Components of Inventories	Inventories consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Aggregate stockpiles $ 143,271 $ 140,461 Finished goods 31,657 33,023 Work in process 10,062 7,664 Raw materials 24,784 23,639 Total $ 209,774 $ 204,787

ACCRUED EXPENSES - (Tables)

ACCRUED EXPENSES - (Tables)	9 Months Ended
	Sep. 26, 2020
Schedule Of Accrued Expenses [Line Items]
Components of Accrued Expenses	Accrued expenses consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Interest $ 11,413 $ 26,892 Payroll and benefits 37,862 29,356 Finance lease obligations 24,868 16,007 Insurance 16,888 14,968 Non-income taxes 18,949 7,666 Deferred asset purchase payments 9,686 3,525 Professional fees 788 902 Other (1) 23,610 20,689 Total $ 144,064 $ 120,005 (1) Consists primarily of current portion of asset retirement obligations and miscellaneous accruals.
Summit Materials, LLC
Schedule Of Accrued Expenses [Line Items]
Components of Accrued Expenses	Accrued expenses consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Interest $ 11,413 $ 26,892 Payroll and benefits 37,862 29,356 Finance lease obligations 24,868 16,007 Insurance 16,888 14,968 Non-income taxes 19,180 7,898 Deferred asset purchase payments 9,686 3,525 Professional fees 788 902 Other (1) 23,610 20,689 Total $ 144,295 $ 120,237 _______________________________________________________________________ (1) Consists primarily of current portion of asset retirement obligations and miscellaneous accruals.

DEBT - (Tables)

DEBT - (Tables)	9 Months Ended
	Sep. 26, 2020
Debt Instrument [Line Items]
Schedule of Debt	Debt consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Term Loan, due 2024: $619.5 million and $624.3 million, net of $0.9 million and $1.1 million discount at September 26, 2020 and December 28, 2019, respectively $ 618,545 $ 623,140 6 1 ⁄ 8 % Senior Notes, due 2023: $650.0 million, net of $0.9 million discount at December 28, 2019 — 649,133 5 1 ⁄ 8 % Senior Notes, due 2025 300,000 300,000 6 1 ⁄ 2 % Senior Notes, due 2027 300,000 300,000 5 1 ⁄ 4 % Senior Notes, due 2029 700,000 — Total 1,918,545 1,872,273 Current portion of long-term debt 7,942 7,942 Long-term debt $ 1,910,603 $ 1,864,331
Schedule of Contractual Payments of Long-Term Debt	The contractual payments of long-term debt, including current maturities, for the five years subsequent to September 26, 2020, are as follows: 2020 (three months) $ 3,177 2021 6,353 2022 6,354 2023 6,354 2024 597,253 2025 300,000 Thereafter 1,000,000 Total 1,919,491 Less: Original issue net discount (946) Less: Capitalized loan costs (17,391) Total debt $ 1,901,154
Summary of Activity for Deferred Financing Fees	The following table presents the activity for the deferred financing fees for the nine months ended September 26, 2020 and September 28, 2019: Deferred financing fees Balance—December 28, 2019 $ 15,436 Loan origination fees 9,565 Amortization (2,499) Write off of deferred financing fees (3,338) Balance—September 26, 2020 $ 19,164 Balance—December 29, 2018 $ 15,475 Loan origination fees 6,312 Amortization (2,668) Write off of deferred financing fees (2,851) Balance—September 28, 2019 $ 16,268
Summit Materials, LLC
Debt Instrument [Line Items]
Schedule of Debt	Debt consisted of the following as of September 26, 2020 and December 28, 2019: September 26, 2020 December 28, 2019 Term Loan, due 2024: $619.5 million and $624.3 million, net of $0.9 million and $1.1 million discount at September 26, 2020 and December 28, 2019, respectively $ 618,545 $ 623,140 6 1/8 % Senior Notes, due 2023: $650.0 million, net of $0.9 million discount at December 28, 2019 — 649,133 5 1/8 % Senior Notes, due 2025 300,000 300,000 6 1/2 % Senior Notes, due 2027 300,000 300,000 5 1/4 % Senior Notes, due 2029 700,000 — Total 1,918,545 1,872,273 Current portion of long-term debt 7,942 7,942 Long-term debt $ 1,910,603 $ 1,864,331
Schedule of Contractual Payments of Long-Term Debt	The contractual payments of long-term debt, including current maturities, for the five years subsequent to September 26, 2020, are as follows: 2020 (three months) $ 3,177 2021 6,353 2022 6,354 2023 6,354 2024 597,253 2025 300,000 Thereafter 1,000,000 Total 1,919,491 Less: Original issue net discount (946) Less: Capitalized loan costs (17,391) Total debt $ 1,901,154
Summary of Activity for Deferred Financing Fees	The following table presents the activity for the deferred financing fees for the nine months ended September 26, 2020 and September 28, 2019: Deferred financing fees Balance—December 28, 2019 $ 15,436 Loan origination fees 9,565 Amortization (2,499) Write off of deferred financing fees (3,338) Balance—September 26, 2020 $ 19,164 Balance - December 29, 2018 $ 15,475 Loan origination fees 6,312 Amortization (2,668) Write off of deferred financing fees (2,851) Balance - September 28, 2019 $ 16,268

EARNINGS PER SHARE - (Tables)

EARNINGS PER SHARE - (Tables)	9 Months Ended
	Sep. 26, 2020
Earnings Per Share [Abstract]
Schedule of Basic Earnings Per Share	The following table shows the calculation of basic and diluted earnings per share: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Net income attributable to Summit Inc. $ 90,730 $ 55,757 $ 102,815 $ 23,395 Weighted average shares of Class A stock outstanding Add: Nonvested restricted stock awards of retirement eligible shares 320,343 — 145,155 — Add: Weighted average shares of Class A stock outstanding 114,116,564 112,179,137 113,943,292 112,020,275 Weighted average basic shares outstanding 114,436,907 112,179,137 114,088,447 112,020,275 Basic earnings per share $ 0.79 $ 0.50 $ 0.90 $ 0.21 Diluted net income attributable to Summit Inc. $ 90,730 $ 55,757 $ 102,815 $ 23,395 Weighted average shares of Class A stock outstanding 114,116,564 112,179,137 113,943,292 112,020,275 Add: weighted average of LP Units — — — — Add: stock options — 2,788,221 — 216,165 Add: warrants — 100,037 — — Add: restricted stock units 263,886 384,571 450,353 222,533 Add: performance stock units 91,721 53,156 63,631 38,637 Weighted average dilutive shares outstanding 114,472,171 115,505,122 114,457,276 112,497,610 Diluted earnings per share $ 0.79 $ 0.48 $ 0.90 $ 0.21
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	Excluded from the above calculations were the shares noted below as they were antidilutive: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Antidilutive shares: LP Units 3,053,115 3,368,058 3,086,819 3,404,231 Time-vesting stock options 2,095,929 — 2,095,929 — Warrants 100,037 — 100,037 100,037

STOCKHOLDERS' EQUITY_MEMBERS'_2

STOCKHOLDERS' EQUITY/MEMBERS' INTEREST - (Tables)	9 Months Ended
	Sep. 26, 2020
Schedule of Capitalization, Equity [Line Items]
Schedule of changes in ownership of Summit Holdings	The following table summarizes the changes in our ownership of Summit Holdings: Summit Inc. LP Units Total Summit Inc. Balance — December 28, 2019 113,309,385 3,249,657 116,559,042 97.2 % Exchanges during period 196,542 (196,542) — Stock option exercises 14,404 — 14,404 Other equity transactions 603,580 — 603,580 Balance — September 26, 2020 114,123,911 3,053,115 117,177,026 97.4 % Balance — December 29, 2018 111,658,927 3,435,518 115,094,445 97.0 % Exchanges during period 107,336 (107,336) — Other equity transactions 509,735 — 509,735 Balance — September 28, 2019 112,275,998 3,328,182 115,604,180 97.1 %
Schedule of Changes in Each Component of Accumulated Other Comprehensive Income (Loss)	The changes in each component of accumulated other comprehensive income (loss) consisted of the following: Change in Foreign currency Cash flow hedge Accumulated Balance — December 28, 2019 $ 2,171 $ 1,277 $ — $ 3,448 Foreign currency translation adjustment, net of tax — (2,473) — (2,473) Balance — September 26, 2020 $ 2,171 $ (1,196) $ — $ 975 Balance — December 29, 2018 $ 3,573 $ (2,147) $ 1,255 $ 2,681 Foreign currency translation adjustment, net of tax — 2,364 — 2,364 Loss on cash flow hedges, net of tax — — (107) (107) Balance — September 28, 2019 $ 3,573 $ 217 $ 1,148 $ 4,938
Summit Materials, LLC
Schedule of Capitalization, Equity [Line Items]
Schedule of Changes in Each Component of Accumulated Other Comprehensive Income (Loss)	The changes in each component of accumulated other comprehensive income (loss) consisted of the following: Accumulated Foreign currency other Change in translation Cash flow hedge comprehensive retirement plans adjustments adjustments (loss) income Balance — December 28, 2019 $ (6,317) $ (14,654) $ — $ (20,971) Foreign currency translation adjustment — (3,395) — (3,395) Balance — September 26, 2020 $ (6,317) $ (18,049) $ — $ (24,366) Balance — December 29, 2018 $ (4,392) $ (19,370) $ 146 $ (23,616) Foreign currency translation adjustment — 3,263 — 3,263 Loss on cash flow hedges — — (148) (148) Balance — September 28, 2019 $ (4,392) $ (16,107) $ (2) $ (20,501)

SUPPLEMENTAL CASH FLOW INFORM_2

SUPPLEMENTAL CASH FLOW INFORMATION - (Tables)	9 Months Ended
	Sep. 26, 2020
Schedule Of Cash Flow Supplemental [Line Items]
Schedule of Supplemental Cash Flow Information	Supplemental cash flow information is as follows: Nine months ended September 26, 2020 September 28, 2019 Cash payments: Interest $ 86,427 $ 89,759 Payments (refunds) for income taxes, net 1,131 (912) Operating cash payments on operating leases 8,372 8,188 Operating cash payments on finance leases 2,402 2,322 Finance cash payments on finance leases 11,528 9,806 Non cash financing activities: Right of use assets obtained in exchange for operating lease obligations $ 2,931 $ 4,387 Right of use assets obtained in exchange for finance leases obligations 17,605 18,586 Exchange of LP Units to shares of Class A common stock 4,648 1,995
Summit Materials, LLC
Schedule Of Cash Flow Supplemental [Line Items]
Schedule of Supplemental Cash Flow Information	Supplemental cash flow information is as follows: Nine months ended September 26, 2020 September 28, 2019 Cash payments: Interest $ 86,427 $ 89,759 Payments (refunds) for income taxes, net 1,131 (912) Operating cash payments on operating leases 8,372 8,188 Operating cash payments on finance leases 2,402 2,322 Finance cash payments on finance leases 11,528 9,806 Non cash financing activities: Right of use assets obtained in exchange for operating lease obligations $ 2,931 $ 4,387 Right of use assets obtained in exchange for finance leases obligations 17,605 18,586

LEASES - (Tables)

LEASES - (Tables)	9 Months Ended
	Sep. 26, 2020
Lessee, Lease, Description [Line Items]
Schedule of Lease Cost	The components of lease expense were as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Operating lease cost $ 2,478 $ 2,608 $ 7,576 $ 7,757 Variable lease cost 90 151 253 366 Short-term lease cost 14,335 11,871 33,369 28,043 Financing lease cost: Amortization of right-of-use assets 3,439 2,612 9,307 7,905 Interest on lease liabilities 780 773 2,329 2,404 Total lease cost $ 21,122 $ 18,015 $ 52,834 $ 46,475 September 26, 2020 December 28, 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 28,551 $ 32,777 Current operating lease liabilities $ 8,193 $ 8,427 Noncurrent operating lease liabilities 21,327 25,381 Total operating lease liabilities $ 29,520 $ 33,808 Finance leases: Property and equipment, gross $ 92,873 $ 82,660 Less accumulated depreciation (29,663) (24,907) Property and equipment, net $ 63,210 $ 57,753 Current finance lease liabilities $ 24,868 $ 16,007 Long-term finance lease liabilities 34,913 40,410 Total finance lease liabilities $ 59,781 $ 56,417 Weighted average remaining lease term (years): Operating leases 9.0 8.6 Finance lease 2.6 2.6 Weighted average discount rate (%): Operating leases 5.4 % 5.5 % Finance lease 5.2 % 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 (three months) $ 2,444 $ 4,995 2021 8,818 26,169 2022 5,475 18,519 2023 4,243 6,867 2024 2,547 3,207 2025 1,507 2,573 Thereafter 12,808 2,831 Total lease payments 37,842 65,161 Less imputed interest (8,322) (5,380) Present value of lease payments $ 29,520 $ 59,781
Schedule of Lease Assets and Liabilities	The components of lease expense were as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Operating lease cost $ 2,478 $ 2,608 $ 7,576 $ 7,757 Variable lease cost 90 151 253 366 Short-term lease cost 14,335 11,871 33,369 28,043 Financing lease cost: Amortization of right-of-use assets 3,439 2,612 9,307 7,905 Interest on lease liabilities 780 773 2,329 2,404 Total lease cost $ 21,122 $ 18,015 $ 52,834 $ 46,475 September 26, 2020 December 28, 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 28,551 $ 32,777 Current operating lease liabilities $ 8,193 $ 8,427 Noncurrent operating lease liabilities 21,327 25,381 Total operating lease liabilities $ 29,520 $ 33,808 Finance leases: Property and equipment, gross $ 92,873 $ 82,660 Less accumulated depreciation (29,663) (24,907) Property and equipment, net $ 63,210 $ 57,753 Current finance lease liabilities $ 24,868 $ 16,007 Long-term finance lease liabilities 34,913 40,410 Total finance lease liabilities $ 59,781 $ 56,417 Weighted average remaining lease term (years): Operating leases 9.0 8.6 Finance lease 2.6 2.6 Weighted average discount rate (%): Operating leases 5.4 % 5.5 % Finance lease 5.2 % 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 (three months) $ 2,444 $ 4,995 2021 8,818 26,169 2022 5,475 18,519 2023 4,243 6,867 2024 2,547 3,207 2025 1,507 2,573 Thereafter 12,808 2,831 Total lease payments 37,842 65,161 Less imputed interest (8,322) (5,380) Present value of lease payments $ 29,520 $ 59,781
Schedule of Finance Lease Liability Maturities	The components of lease expense were as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Operating lease cost $ 2,478 $ 2,608 $ 7,576 $ 7,757 Variable lease cost 90 151 253 366 Short-term lease cost 14,335 11,871 33,369 28,043 Financing lease cost: Amortization of right-of-use assets 3,439 2,612 9,307 7,905 Interest on lease liabilities 780 773 2,329 2,404 Total lease cost $ 21,122 $ 18,015 $ 52,834 $ 46,475 September 26, 2020 December 28, 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 28,551 $ 32,777 Current operating lease liabilities $ 8,193 $ 8,427 Noncurrent operating lease liabilities 21,327 25,381 Total operating lease liabilities $ 29,520 $ 33,808 Finance leases: Property and equipment, gross $ 92,873 $ 82,660 Less accumulated depreciation (29,663) (24,907) Property and equipment, net $ 63,210 $ 57,753 Current finance lease liabilities $ 24,868 $ 16,007 Long-term finance lease liabilities 34,913 40,410 Total finance lease liabilities $ 59,781 $ 56,417 Weighted average remaining lease term (years): Operating leases 9.0 8.6 Finance lease 2.6 2.6 Weighted average discount rate (%): Operating leases 5.4 % 5.5 % Finance lease 5.2 % 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 (three months) $ 2,444 $ 4,995 2021 8,818 26,169 2022 5,475 18,519 2023 4,243 6,867 2024 2,547 3,207 2025 1,507 2,573 Thereafter 12,808 2,831 Total lease payments 37,842 65,161 Less imputed interest (8,322) (5,380) Present value of lease payments $ 29,520 $ 59,781
Schedule of Operating Lease Liability Maturities	The components of lease expense were as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Operating lease cost $ 2,478 $ 2,608 $ 7,576 $ 7,757 Variable lease cost 90 151 253 366 Short-term lease cost 14,335 11,871 33,369 28,043 Financing lease cost: Amortization of right-of-use assets 3,439 2,612 9,307 7,905 Interest on lease liabilities 780 773 2,329 2,404 Total lease cost $ 21,122 $ 18,015 $ 52,834 $ 46,475 September 26, 2020 December 28, 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 28,551 $ 32,777 Current operating lease liabilities $ 8,193 $ 8,427 Noncurrent operating lease liabilities 21,327 25,381 Total operating lease liabilities $ 29,520 $ 33,808 Finance leases: Property and equipment, gross $ 92,873 $ 82,660 Less accumulated depreciation (29,663) (24,907) Property and equipment, net $ 63,210 $ 57,753 Current finance lease liabilities $ 24,868 $ 16,007 Long-term finance lease liabilities 34,913 40,410 Total finance lease liabilities $ 59,781 $ 56,417 Weighted average remaining lease term (years): Operating leases 9.0 8.6 Finance lease 2.6 2.6 Weighted average discount rate (%): Operating leases 5.4 % 5.5 % Finance lease 5.2 % 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 (three months) $ 2,444 $ 4,995 2021 8,818 26,169 2022 5,475 18,519 2023 4,243 6,867 2024 2,547 3,207 2025 1,507 2,573 Thereafter 12,808 2,831 Total lease payments 37,842 65,161 Less imputed interest (8,322) (5,380) Present value of lease payments $ 29,520 $ 59,781
Summit Materials, LLC
Lessee, Lease, Description [Line Items]
Schedule of Lease Cost	The components of lease expense were as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Operating lease cost $ 2,478 $ 2,608 $ 7,576 $ 7,757 Variable lease cost 90 151 253 366 Short-term lease cost 14,335 11,871 33,369 28,043 Financing lease cost: Amortization of right-of-use assets 3,439 2,612 9,307 7,905 Interest on lease liabilities 780 773 2,329 2,404 Total lease cost $ 21,122 $ 18,015 $ 52,834 $ 46,475 September 26, 2020 December 28, 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 28,551 $ 32,777 Current operating lease liabilities $ 8,193 $ 8,427 Noncurrent operating lease liabilities 21,327 25,381 Total operating lease liabilities $ 29,520 $ 33,808 Finance leases: Property and equipment, gross $ 92,873 $ 82,660 Less accumulated depreciation (29,663) (24,907) Property and equipment, net $ 63,210 $ 57,753 Current finance lease liabilities $ 24,868 $ 16,007 Long-term finance lease liabilities 34,913 40,410 Total finance lease liabilities $ 59,781 $ 56,417 Weighted average remaining lease term (years): Operating leases 9.0 8.6 Finance lease 2.6 2.6 Weighted average discount rate (%): Operating leases 5.4 % 5.5 % Finance lease 5.2 % 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 (three months) $ 2,444 $ 4,995 2021 8,818 26,169 2022 5,475 18,519 2023 4,243 6,867 2024 2,547 3,207 2025 1,507 2,573 Thereafter 12,808 2,831 Total lease payments 37,842 65,161 Less imputed interest (8,322) (5,380) Present value of lease payments $ 29,520 $ 59,781
Schedule of Lease Assets and Liabilities	The components of lease expense were as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Operating lease cost $ 2,478 $ 2,608 $ 7,576 $ 7,757 Variable lease cost 90 151 253 366 Short-term lease cost 14,335 11,871 33,369 28,043 Financing lease cost: Amortization of right-of-use assets 3,439 2,612 9,307 7,905 Interest on lease liabilities 780 773 2,329 2,404 Total lease cost $ 21,122 $ 18,015 $ 52,834 $ 46,475 September 26, 2020 December 28, 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 28,551 $ 32,777 Current operating lease liabilities $ 8,193 $ 8,427 Noncurrent operating lease liabilities 21,327 25,381 Total operating lease liabilities $ 29,520 $ 33,808 Finance leases: Property and equipment, gross $ 92,873 $ 82,660 Less accumulated depreciation (29,663) (24,907) Property and equipment, net $ 63,210 $ 57,753 Current finance lease liabilities $ 24,868 $ 16,007 Long-term finance lease liabilities 34,913 40,410 Total finance lease liabilities $ 59,781 $ 56,417 Weighted average remaining lease term (years): Operating leases 9.0 8.6 Finance lease 2.6 2.6 Weighted average discount rate (%): Operating leases 5.4 % 5.5 % Finance lease 5.2 % 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 (three months) $ 2,444 $ 4,995 2021 8,818 26,169 2022 5,475 18,519 2023 4,243 6,867 2024 2,547 3,207 2025 1,507 2,573 Thereafter 12,808 2,831 Total lease payments 37,842 65,161 Less imputed interest (8,322) (5,380) Present value of lease payments $ 29,520 $ 59,781
Schedule of Finance Lease Liability Maturities	The components of lease expense were as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Operating lease cost $ 2,478 $ 2,608 $ 7,576 $ 7,757 Variable lease cost 90 151 253 366 Short-term lease cost 14,335 11,871 33,369 28,043 Financing lease cost: Amortization of right-of-use assets 3,439 2,612 9,307 7,905 Interest on lease liabilities 780 773 2,329 2,404 Total lease cost $ 21,122 $ 18,015 $ 52,834 $ 46,475 September 26, 2020 December 28, 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 28,551 $ 32,777 Current operating lease liabilities $ 8,193 $ 8,427 Noncurrent operating lease liabilities 21,327 25,381 Total operating lease liabilities $ 29,520 $ 33,808 Finance leases: Property and equipment, gross $ 92,873 $ 82,660 Less accumulated depreciation (29,663) (24,907) Property and equipment, net $ 63,210 $ 57,753 Current finance lease liabilities $ 24,868 $ 16,007 Long-term finance lease liabilities 34,913 40,410 Total finance lease liabilities $ 59,781 $ 56,417 Weighted average remaining lease term (years): Operating leases 9.0 8.6 Finance lease 2.6 2.6 Weighted average discount rate (%): Operating leases 5.4 % 5.5 % Finance lease 5.2 % 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 (three months) $ 2,444 $ 4,995 2021 8,818 26,169 2022 5,475 18,519 2023 4,243 6,867 2024 2,547 3,207 2025 1,507 2,573 Thereafter 12,808 2,831 Total lease payments 37,842 65,161 Less imputed interest (8,322) (5,380) Present value of lease payments $ 29,520 $ 59,781
Schedule of Operating Lease Liability Maturities	The components of lease expense were as follows: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Operating lease cost $ 2,478 $ 2,608 $ 7,576 $ 7,757 Variable lease cost 90 151 253 366 Short-term lease cost 14,335 11,871 33,369 28,043 Financing lease cost: Amortization of right-of-use assets 3,439 2,612 9,307 7,905 Interest on lease liabilities 780 773 2,329 2,404 Total lease cost $ 21,122 $ 18,015 $ 52,834 $ 46,475 September 26, 2020 December 28, 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 28,551 $ 32,777 Current operating lease liabilities $ 8,193 $ 8,427 Noncurrent operating lease liabilities 21,327 25,381 Total operating lease liabilities $ 29,520 $ 33,808 Finance leases: Property and equipment, gross $ 92,873 $ 82,660 Less accumulated depreciation (29,663) (24,907) Property and equipment, net $ 63,210 $ 57,753 Current finance lease liabilities $ 24,868 $ 16,007 Long-term finance lease liabilities 34,913 40,410 Total finance lease liabilities $ 59,781 $ 56,417 Weighted average remaining lease term (years): Operating leases 9.0 8.6 Finance lease 2.6 2.6 Weighted average discount rate (%): Operating leases 5.4 % 5.5 % Finance lease 5.2 % 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 (three months) $ 2,444 $ 4,995 2021 8,818 26,169 2022 5,475 18,519 2023 4,243 6,867 2024 2,547 3,207 2025 1,507 2,573 Thereafter 12,808 2,831 Total lease payments 37,842 65,161 Less imputed interest (8,322) (5,380) Present value of lease payments $ 29,520 $ 59,781

FAIR VALUE - (Tables)

FAIR VALUE - (Tables)	9 Months Ended
	Sep. 26, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Schedule of Contingent Consideration and Derivatives Measured at Fair Value	The fair value of contingent consideration as of September 26, 2020 and December 28, 2019 was: September 26, 2020 December 28, 2019 Current portion of acquisition-related liabilities and Accrued expenses: Contingent consideration $ 525 $ 1,967 Acquisition-related liabilities and Other noncurrent liabilities: Contingent consideration $ 1,303 $ 1,302
Schedule of Carrying Value and Fair Value of Financial Instruments	The carrying value and fair value of these financial instruments as of September 26, 2020 and December 28, 2019 was: September 26, 2020 December 28, 2019 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt(1) $ 1,939,247 $ 1,918,545 $ 1,918,720 $ 1,872,273 Level 3 Current portion of deferred consideration and noncompete obligations(2) 31,443 31,443 30,733 30,733 Long term portion of deferred consideration and noncompete obligations(3) 11,573 11,573 18,499 18,499 (1) $7.9 million was included in current portion of debt as of September 26, 2020 and December 28, 2019. (2) Included in current portion of acquisition-related liabilities on the consolidated balance sheets. (3) Included in acquisition-related liabilities on the consolidated balance sheets.
Summit Materials, LLC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Schedule of Contingent Consideration and Derivatives Measured at Fair Value	The fair value of contingent consideration as of September 26, 2020 and December 28, 2019 was: September 26, 2020 December 28, 2019 Current portion of acquisition-related liabilities and Accrued expenses: Contingent consideration $ 525 $ 1,967 Acquisition-related liabilities and Other noncurrent liabilities: Contingent consideration $ 1,303 $ 1,302
Schedule of Carrying Value and Fair Value of Financial Instruments	The carrying value and fair value of these financial instruments as of September 26, 2020 and December 28, 2019 was: September 26, 2020 December 28, 2019 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt(1) $ 1,939,247 $ 1,918,545 $ 1,918,720 $ 1,872,273 Level 3 Current portion of deferred consideration and noncompete obligations(2) 29,067 29,067 28,233 28,233 Long term portion of deferred consideration and noncompete obligations(3) 11,573 11,573 16,364 16,364 (1) $7.9 million was included in current portion of debt as of September 26, 2020 and December 28, 2019. (2) Included in current portion of acquisition-related liabilities on the consolidated balance sheets. (3) Included in acquisition-related liabilities on the consolidated balance sheets.

SEGMENT INFORMATION - (Tables)

SEGMENT INFORMATION - (Tables)	9 Months Ended
	Sep. 26, 2020
Segment Reporting Information [Line Items]
Summary of Financial Data for Company's Reportable Business Segments	The following tables display selected financial data for the Company’s reportable business segments as of September 26, 2020 and December 28, 2019 and for the three and nine months ended September 26, 2020 and September 28, 2019: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Revenue*: West $ 390,310 $ 366,504 $ 919,016 $ 848,661 East 234,435 266,587 590,341 596,107 Cement 84,874 98,991 198,461 220,844 Total revenue $ 709,619 $ 732,082 $ 1,707,818 $ 1,665,612 *Intercompany sales are immaterial and the presentation above only reflects sales to external customers. Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Income from operations before taxes $ 73,156 $ 103,839 $ 79,597 $ 58,998 Interest expense 24,623 28,917 78,049 88,423 Depreciation, depletion and amortization 57,364 54,575 161,912 162,417 Accretion 690 552 1,848 1,723 Loss on debt financings 4,064 — 4,064 14,565 Transaction costs 445 751 1,517 1,449 Non-cash compensation 13,322 4,819 23,119 15,424 Other 4,083 (136) 4,287 (2,628) Total Adjusted EBITDA $ 177,747 $ 193,317 $ 354,393 $ 340,371 Total Adjusted EBITDA by Segment: West $ 95,470 $ 81,936 $ 196,881 $ 151,054 East 56,943 76,825 119,900 134,479 Cement 35,086 42,683 63,172 75,537 Corporate and other (9,752) (8,127) (25,560) (20,699) Total Adjusted EBITDA $ 177,747 $ 193,317 $ 354,393 $ 340,371 Nine months ended September 26, 2020 September 28, 2019 Purchases of property, plant and equipment West $ 51,148 $ 61,679 East 75,006 61,830 Cement 12,097 15,087 Total reportable segments 138,251 138,596 Corporate and other 1,755 1,166 Total purchases of property, plant and equipment $ 140,006 $ 139,762 Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Depreciation, depletion, amortization and accretion: West $ 23,117 $ 23,307 $ 67,082 $ 70,156 East 22,803 19,668 65,293 59,719 Cement 11,155 11,111 28,425 31,280 Total reportable segments 57,075 54,086 160,800 161,155 Corporate and other 979 1,041 2,960 2,985 Total depreciation, depletion, amortization and accretion $ 58,054 $ 55,127 $ 163,760 $ 164,140 September 26, 2020 December 28, 2019 Total assets: West $ 1,540,792 $ 1,379,684 East 1,347,883 1,288,835 Cement 868,458 868,528 Total reportable segments 3,757,133 3,537,047 Corporate and other 535,037 530,509 Total $ 4,292,170 $ 4,067,556
Summit Materials, LLC
Segment Reporting Information [Line Items]
Summary of Financial Data for Company's Reportable Business Segments	The following tables display selected financial data for the Company’s reportable business segments as of September 26, 2020 and December 28, 2019 and for the three and nine months ended September 26, 2020 and September 28, 2019: Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Revenue*: West $ 390,310 $ 366,504 $ 919,016 $ 848,661 East 234,435 266,587 590,341 596,107 Cement 84,874 98,991 198,461 220,844 Total revenue $ 709,619 $ 732,082 $ 1,707,818 $ 1,665,612 *Intercompany sales are immaterial and the presentation above only reflects sales to external customers. Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Income from operations before taxes $ 73,218 $ 103,956 $ 79,839 $ 59,401 Interest expense 24,561 28,800 77,807 88,020 Depreciation, depletion and amortization 57,364 54,575 161,912 162,417 Accretion 690 552 1,848 1,723 Loss on debt financings 4,064 — 4,064 14,565 Transaction costs 445 751 1,517 1,449 Non-cash compensation 13,322 4,819 23,119 15,424 Other 4,083 (136) 4,287 (2,628) Total Adjusted EBITDA $ 177,747 $ 193,317 $ 354,393 $ 340,371 Total Adjusted EBITDA by Segment: West $ 95,470 $ 81,936 $ 196,881 $ 151,054 East 56,943 76,825 119,900 134,479 Cement 35,086 42,683 63,172 75,537 Corporate and other (9,752) (8,127) (25,560) (20,699) Total Adjusted EBITDA $ 177,747 $ 193,317 $ 354,393 $ 340,371 Nine months ended September 26, 2020 September 28, 2019 Purchases of property, plant and equipment West $ 51,148 $ 61,679 East 75,006 61,830 Cement 12,097 15,087 Total reportable segments 138,251 138,596 Corporate and other 1,755 1,166 Total purchases of property, plant and equipment $ 140,006 $ 139,762 Three months ended Nine months ended September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Depreciation, depletion, amortization and accretion: West $ 23,117 $ 23,307 $ 67,082 $ 70,156 East 22,803 19,668 65,293 59,719 Cement 11,155 11,111 28,425 31,280 Total reportable segments 57,075 54,086 160,800 161,155 Corporate and other 979 1,041 2,960 2,985 Total depreciation, depletion, amortization and accretion $ 58,054 $ 55,127 $ 163,760 $ 164,140 September 26, 2020 December 28, 2019 Total assets: West $ 1,540,792 $ 1,379,684 East 1,347,883 1,288,835 Cement 868,458 868,528 Total reportable segments 3,757,133 3,537,047 Corporate and other 294,137 319,176 Total $ 4,051,270 $ 3,856,223

GUARANTOR AND NON-GUARANTOR F_2

GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - (Tables) - Summit Materials, LLC	9 Months Ended
	Sep. 26, 2020
Condensed Consolidating Balance Sheets	Condensed Consolidating Balance Sheets September 26, 2020 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Assets Current assets: Cash and cash equivalents $ 277,052 $ 3,350 $ 12,943 $ (4,588) $ 288,757 Accounts receivable, net 1 289,977 19,486 (87) 309,377 Intercompany receivables 424,533 1,128,619 — (1,553,152) — Cost and estimated earnings in excess of billings — 40,711 3,290 — 44,001 Inventories — 203,217 6,557 — 209,774 Other current assets 2,219 9,724 1,689 — 13,632 Total current assets 703,805 1,675,598 43,965 (1,557,827) 865,541 Property, plant and equipment, net 10,383 1,691,382 61,301 — 1,763,066 Goodwill — 1,222,786 81,300 — 1,304,086 Intangible assets, net — 37,923 — — 37,923 Operating lease right-of-use assets 2,793 21,647 4,111 — 28,551 Other assets 3,922,503 197,286 671 (4,068,357) 52,103 Total assets $ 4,639,484 $ 4,846,622 $ 191,348 $ (5,626,184) $ 4,051,270 Liabilities and Member’s Interest Current liabilities: Current portion of debt $ 7,942 $ — $ — $ — $ 7,942 Current portion of acquisition-related liabilities — 29,592 — — 29,592 Accounts payable 5,935 135,658 8,580 (87) 150,086 Accrued expenses 37,693 105,201 5,989 (4,588) 144,295 Current operating lease liabilities 874 6,239 1,080 — 8,193 Intercompany payables 1,072,127 469,880 11,145 (1,553,152) — Billings in excess of costs and estimated earnings — 13,139 1,086 — 14,225 Total current liabilities 1,124,571 759,709 27,880 (1,557,827) 354,333 Long-term debt 1,893,212 — — — 1,893,212 Acquisition-related liabilities — 12,876 — — 12,876 Noncurrent operating lease liabilities 2,801 15,600 2,926 — 21,327 Other noncurrent liabilities 4,389 207,881 107,162 (164,421) 155,011 Total liabilities 3,024,973 996,066 137,968 (1,722,248) 2,436,759 Total member's interest 1,614,511 3,850,556 53,380 (3,903,936) 1,614,511 Total liabilities and member’s interest $ 4,639,484 $ 4,846,622 $ 191,348 $ (5,626,184) $ 4,051,270 Condensed Consolidating Balance Sheets December 28, 2019 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Assets Current assets: Cash and cash equivalents $ 302,474 $ 5,488 $ 9,834 $ (6,477) $ 311,319 Accounts receivable, net — 234,053 19,236 (33) 253,256 Intercompany receivables 443,323 942,385 — (1,385,708) — Cost and estimated earnings in excess of billings — 12,291 797 — 13,088 Inventories — 199,794 4,993 — 204,787 Other current assets 1,763 10,308 1,760 — 13,831 Total current assets 747,560 1,404,319 36,620 (1,392,218) 796,281 Property, plant and equipment, net 11,602 1,674,443 61,404 — 1,747,449 Goodwill — 1,142,063 58,636 — 1,200,699 Intangible assets, net — 23,498 — — 23,498 Operating lease right-of-use assets 3,316 24,551 4,910 — 32,777 Other assets 3,596,161 168,314 734 (3,709,690) 55,519 Total assets $ 4,358,639 $ 4,437,188 $ 162,304 $ (5,101,908) $ 3,856,223 Liabilities and Member’s Interest Current liabilities: Current portion of debt $ 7,942 $ — $ — $ — $ 7,942 Current portion of acquisition-related liabilities — 30,200 — — 30,200 Accounts payable 4,588 103,812 8,603 (33) 116,970 Accrued expenses 51,043 72,970 2,701 (6,477) 120,237 Current operating lease liabilities 764 6,571 1,092 — 8,427 Intercompany payables 922,356 447,827 15,525 (1,385,708) — Billings in excess of costs and estimated earnings — 12,183 1,681 — 13,864 Total current liabilities 986,693 673,563 29,602 (1,392,218) 297,640 Long-term debt 1,851,057 — — — 1,851,057 Acquisition-related liabilities — 17,666 — — 17,666 Noncurrent operating lease liabilities 3,480 18,047 3,854 — 25,381 Other noncurrent liabilities 4,259 203,919 80,169 (137,018) 151,329 Total liabilities 2,845,489 913,195 113,625 (1,529,236) 2,343,073 Total member's interest 1,513,150 3,523,993 48,679 (3,572,672) 1,513,150 Total liabilities and member’s interest $ 4,358,639 $ 4,437,188 $ 162,304 $ (5,101,908) $ 3,856,223
Condensed Consolidating Statements of Operations and Comprehensive Loss	Condensed Consolidating Statements of Operations For the three months ended September 26, 2020 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 689,842 $ 23,780 $ (4,003) $ 709,619 Cost of revenue (excluding items shown separately below) — 458,028 14,979 (4,003) 469,004 General and administrative expenses 23,955 55,242 2,747 — 81,944 Depreciation, depletion, amortization and accretion 980 55,542 1,532 — 58,054 Operating (loss) income (24,935) 121,030 4,522 — 100,617 Other (income) loss, net (134,672) (889) (276) 138,675 2,838 Interest expense (income) 31,170 (7,990) 1,381 — 24,561 Income from operation before taxes 78,567 129,909 3,417 (138,675) 73,218 Income tax expense (benefit) 243 (6,286) 937 — (5,106) Net income attributable to Summit LLC $ 78,324 $ 136,195 $ 2,480 $ (138,675) $ 78,324 Comprehensive income attributable to member of Summit Materials, LLC $ 80,342 $ 136,195 $ 462 $ (136,657) $ 80,342 Condensed Consolidating Statements of Operations For the nine months ended September 26, 2020 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 1,659,526 $ 61,556 $ (13,264) $ 1,707,818 Cost of revenue (excluding items shown separately below) — 1,138,689 39,892 (13,264) 1,165,317 General and administrative expenses 50,964 160,670 8,150 — 219,784 Depreciation, depletion, amortization and accretion 2,960 156,697 4,103 — 163,760 Operating (loss) income (53,924) 203,470 9,411 — 158,957 Other (income) loss, net (235,001) (1,733) 271 237,774 1,311 Interest expense (income) 95,379 (21,352) 3,780 — 77,807 Income from operation before taxes 85,698 226,555 5,360 (237,774) 79,839 Income tax expense (benefit) 982 (7,383) 1,524 — (4,877) Net income attributable to Summit LLC $ 84,716 $ 233,938 $ 3,836 $ (237,774) $ 84,716 Comprehensive income attributable to member of Summit Materials, LLC $ 81,321 $ 233,938 $ 7,231 $ (241,169) $ 81,321 Condensed Consolidating Statements of Operations For the three months ended September 28, 2019 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 706,999 $ 29,186 $ (4,103) $ 732,082 Cost of revenue (excluding items shown separately below) — 467,595 19,487 (4,103) 482,979 General and administrative expenses 13,603 46,816 2,676 — 63,095 Depreciation, depletion, amortization and accretion 1,042 52,739 1,346 — 55,127 Operating (loss) income (14,645) 139,849 5,677 — 130,881 Other (income) loss, net (132,261) (1,501) 222 131,665 (1,875) Interest expense (income) 32,129 (4,532) 1,203 — 28,800 Income from operation before taxes 85,487 145,882 4,252 (131,665) 103,956 Income tax expense 288 17,325 1,144 — 18,757 Net income attributable to Summit LLC $ 85,199 $ 128,557 $ 3,108 $ (131,665) $ 85,199 Comprehensive income attributable to member of Summit Materials, LLC $ 84,026 $ 128,402 $ 4,436 $ (132,838) $ 84,026 Condensed Consolidating Statements of Operations For the nine months ended September 28, 2019 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 1,603,338 $ 70,321 $ (8,047) $ 1,665,612 Cost of revenue (excluding items shown separately below) — 1,114,401 49,122 (8,047) 1,155,476 General and administrative expenses 37,887 146,136 8,341 — 192,364 Depreciation, depletion, amortization and accretion 2,986 156,827 4,327 — 164,140 Operating (loss) income (40,873) 185,974 8,531 — 153,632 Other (income) loss, net (183,971) (6,427) (553) 197,162 6,211 Interest expense (income) 94,848 (10,443) 3,615 — 88,020 Income from operation before taxes 48,250 202,844 5,469 (197,162) 59,401 Income tax expense 1,114 9,673 1,478 — 12,265 Net income attributable to Summit LLC $ 47,136 $ 193,171 $ 3,991 $ (197,162) $ 47,136 Comprehensive income attributable to member of Summit Materials, LLC $ 50,251 $ 193,319 $ 728 $ (194,047) $ 50,251
Condensed Consolidating Statements of Cash Flows	Condensed Consolidating Statements of Cash Flows For the nine months ended September 26, 2020 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Net cash (used in) provided by operating activities $ (110,054) $ 288,198 $ 39,895 $ — $ 218,039 Cash flow from investing activities: Acquisitions, net of cash acquired — (92,085) (31,110) — (123,195) Purchase of property, plant and equipment (1,755) (136,670) (1,581) — (140,006) Proceeds from the sale of property, plant, and equipment — 8,708 140 — 8,848 Other — 1,395 — — 1,395 Net cash used for investing activities (1,755) (218,652) (32,551) — (252,958) Cash flow from financing activities: Proceeds from investment by member (91,856) 87,925 4,260 — 329 Net proceeds from debt issuance 700,000 — — — 700,000 Loans received from and payments made on loans from other Summit Companies 145,896 (139,650) (8,135) 1,889 — Payments on long-term debt (654,765) (11,983) (144) — (666,892) Payments on acquisition-related liabilities — (7,891) — — (7,891) Debt issuance costs (9,565) — — — (9,565) Distributions from partnership (2,500) — — — (2,500) Other (823) (85) — — (908) Net cash provided by (used in) financing activities 86,387 (71,684) (4,019) 1,889 12,573 Impact of cash on foreign currency — — (216) — (216) Net (decrease) increase in cash (25,422) (2,138) 3,109 1,889 (22,562) Cash — Beginning of period 302,474 5,488 9,834 (6,477) 311,319 Cash — End of period $ 277,052 $ 3,350 $ 12,943 $ (4,588) $ 288,757 Condensed Consolidating Statements of Cash Flows For the nine months ended September 28, 2019 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Net cash (used in) provided by operating activities $ (85,516) $ 241,172 $ 8,187 $ — $ 163,843 Cash flow from investing activities: Acquisitions, net of cash acquired — (2,842) — — (2,842) Purchase of property, plant and equipment (1,166) (129,170) (9,426) — (139,762) Proceeds from the sale of property, plant, and equipment — 12,950 85 — 13,035 Other — (207) — — (207) Net cash used for investing activities (1,166) (119,269) (9,341) — (129,776) Cash flow from financing activities: Proceeds from investment by member (35,581) 38,140 — — 2,559 Net proceeds from debt issuance 300,000 — — — 300,000 Loans received from and payments made on loans from other Summit Companies 147,325 (147,782) 506 (49) — Payments on long-term debt (254,765) (9,965) (176) — (264,906) Payments on acquisition-related liabilities — (8,500) — — (8,500) Financing costs (6,312) — — — (6,312) Distributions from partnership (2,500) — — — (2,500) Other (462) (39) — — (501) Net cash provided by (used in) financing activities 147,705 (128,146) 330 (49) 19,840 Impact of cash on foreign currency — — 174 — 174 Net increase (decrease) in cash 61,023 (6,243) (650) (49) 54,081 Cash — Beginning of period 117,219 8,440 7,719 (4,870) 128,508 Cash — End of period $ 178,242 $ 2,197 $ 7,069 $ (4,919) $ 182,589

SUMMARY OF ORGANIZATION AND S_3

SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES - General Information (Details)	9 Months Ended
	Sep. 26, 2020segmentplant
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Number of operating segments	3
Number of reportable segments	3
Cement plant
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Number of plants | plant	2
Summit Materials, LLC
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Number of operating segments	3
Number of reportable segments	3
Summit Materials, LLC | Cement plant
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Number of plants | plant	2

SUMMARY OF ORGANIZATION AND S_4

SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES - Business and Credit Concentration, Tax Receivable Agreement (Details)	9 Months Ended
	Sep. 26, 2020state
Summit Materials, LLC
Business and Credit Concentrations
Number of states in which the entity operates	23
Tax Receivable Agreement | Summit Holdings LP
Business and Credit Concentrations
Percentage of benefits to be paid on tax receivable agreement	85.00%
Percentage of the tax receivable agreement allocated to additional paid-in capital	15.00%

ACQUISITIONS, GOODWILL AND IN_3

ACQUISITIONS, GOODWILL AND INTANGIBLES - Summary of Number of Acquisitions by Segment (Details) - acquistiion	9 Months Ended	12 Months Ended
	Sep. 26, 2020	Dec. 28, 2019
West
Business Acquisition [Line Items]
Number of businesses acquired	2	2
West | Summit Materials, LLC
Business Acquisition [Line Items]
Number of businesses acquired	2	2
East
Business Acquisition [Line Items]
Number of businesses acquired	1	0
East | Summit Materials, LLC
Business Acquisition [Line Items]
Number of businesses acquired	1	0

ACQUISITIONS, GOODWILL AND IN_4

ACQUISITIONS, GOODWILL AND INTANGIBLES - Schedule of Business Combination Recognizable Assets and Liabilities Assumed (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 26, 2020	Dec. 28, 2019
Business Acquisition [Line Items]
Goodwill	$ 1,303,086	$ 1,199,699
Summit Materials, LLC
Business Acquisition [Line Items]
Goodwill	1,304,086	1,200,699
Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Financial assets	8,866	0
Inventories	2,328	52
Property, plant and equipment	17,069	3,542
Other assets	758	0
Financial liabilities	(3,980)	(36)
Other long-term liabilities	(6,473)	0
Net assets acquired	18,568	3,558
Goodwill	105,280	1,834
Purchase price	123,848	5,392
Other	(652)	0
Net cash paid for acquisitions	123,196	5,392
Series of Individually Immaterial Business Acquisitions | Summit Materials, LLC
Business Acquisition [Line Items]
Financial assets	8,866	0
Inventories	2,328	52
Property, plant and equipment	17,069	3,542
Other assets	758	0
Financial liabilities	(3,980)	(36)
Other long-term liabilities	(6,473)	0
Net assets acquired	18,568	3,558
Goodwill	105,280	1,834
Purchase price	123,848	5,392
Other	(652)	0
Net cash paid for acquisitions	$ 123,196	$ 5,392

ACQUISITIONS, GOODWILL AND IN_5

ACQUISITIONS, GOODWILL AND INTANGIBLES - Summary of Goodwill by Reportable Segments (Details) $ in Thousands	9 Months Ended
	Sep. 26, 2020USD ($)
Goodwill [Roll Forward]
Balance—December 28, 2019	$ 1,199,699
Acquisitions	105,298
Foreign currency translation adjustments	(1,911)
Balance—September 26, 2020	1,303,086
West
Goodwill [Roll Forward]
Balance—December 28, 2019	584,617
Acquisitions	105,298
Foreign currency translation adjustments	(1,911)
Balance—September 26, 2020	688,004
East
Goodwill [Roll Forward]
Balance—December 28, 2019	410,426
Acquisitions	0
Foreign currency translation adjustments	0
Balance—September 26, 2020	410,426
Cement
Goodwill [Roll Forward]
Balance—December 28, 2019	204,656
Acquisitions	0
Foreign currency translation adjustments	0
Balance—September 26, 2020	204,656
Summit Materials, LLC
Goodwill [Roll Forward]
Balance—December 28, 2019	1,200,699
Acquisitions	105,298
Foreign currency translation adjustments	(1,911)
Balance—September 26, 2020	1,304,086
Summit Materials, LLC | West
Goodwill [Roll Forward]
Balance—December 28, 2019	585,617
Acquisitions	105,298
Foreign currency translation adjustments	(1,911)
Balance—September 26, 2020	689,004
Summit Materials, LLC | East
Goodwill [Roll Forward]
Balance—December 28, 2019	410,426
Acquisitions	0
Foreign currency translation adjustments	0
Balance—September 26, 2020	410,426
Summit Materials, LLC | Cement
Goodwill [Roll Forward]
Balance—December 28, 2019	204,656
Acquisitions	0
Foreign currency translation adjustments	0
Balance—September 26, 2020	$ 204,656

ACQUISITIONS, GOODWILL AND IN_6

ACQUISITIONS, GOODWILL AND INTANGIBLES - Intangible Assets By Type (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 50,390	$ 33,864
Accumulated Amortization	(12,467)	(10,366)
Net Carrying Amount	37,923	23,498
Operating permits
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	23,345	6,609
Accumulated Amortization	(1,162)	(290)
Net Carrying Amount	22,183	6,319
Mineral leases
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	19,225	19,064
Accumulated Amortization	(7,286)	(6,408)
Net Carrying Amount	11,939	12,656
Reserve rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6,234	6,234
Accumulated Amortization	(2,444)	(2,248)
Net Carrying Amount	3,790	3,986
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,000	1,000
Accumulated Amortization	(1,000)	(958)
Net Carrying Amount	0	42
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	586	957
Accumulated Amortization	(575)	(462)
Net Carrying Amount	11	495
Summit Materials, LLC
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	50,390	33,864
Accumulated Amortization	(12,467)	(10,366)
Net Carrying Amount	37,923	23,498
Summit Materials, LLC | Operating permits
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	23,345	6,609
Accumulated Amortization	(1,162)	(290)
Net Carrying Amount	22,183	6,319
Summit Materials, LLC | Mineral leases
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	19,225	19,064
Accumulated Amortization	(7,286)	(6,408)
Net Carrying Amount	11,939	12,656
Summit Materials, LLC | Reserve rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6,234	6,234
Accumulated Amortization	(2,444)	(2,248)
Net Carrying Amount	3,790	3,986
Summit Materials, LLC | Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,000	1,000
Accumulated Amortization	(1,000)	(958)
Net Carrying Amount	0	42
Summit Materials, LLC | Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	586	957
Accumulated Amortization	(575)	(462)
Net Carrying Amount	$ 11	$ 495

ACQUISITIONS, GOODWILL AND IN_7

ACQUISITIONS, GOODWILL AND INTANGIBLES - Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019
Business Acquisition [Line Items]
Amortization expense	$ 700	$ 600	$ 2,300	$ 1,400
Estimated amortization expense
2020 (three months)	686		686
2021	2,719		2,719
2022	2,723		2,723
2023	2,590		2,590
2024	2,495		2,495
2025	2,450		2,450
Thereafter	24,260		24,260
Intangible assets, net	37,923		37,923		$ 23,498
Summit Materials, LLC
Business Acquisition [Line Items]
Amortization expense	700	$ 600	2,300	$ 1,400
Estimated amortization expense
2020 (three months)	686		686
2021	2,719		2,719
2022	2,723		2,723
2023	2,590		2,590
2024	2,495		2,495
2025	2,450		2,450
Thereafter	24,260		24,260
Intangible assets, net	$ 37,923		$ 37,923		$ 23,498

REVENUE RECOGNITION - By Produc

REVENUE RECOGNITION - By Product (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Revenue from External Customer [Line Items]
Total revenue	$ 709,619	$ 732,082	$ 1,707,818	$ 1,665,612
Aggregates
Revenue from External Customer [Line Items]
Total revenue	136,396	137,528	362,546	354,050
Cement
Revenue from External Customer [Line Items]
Total revenue	82,698	92,482	188,854	202,780
Ready-mix concrete
Revenue from External Customer [Line Items]
Total revenue	179,124	172,758	488,710	444,258
Asphalt
Revenue from External Customer [Line Items]
Total revenue	128,125	137,753	255,992	254,156
Paving and related services
Revenue from External Customer [Line Items]
Total revenue	136,191	138,083	280,446	267,732
Other
Revenue from External Customer [Line Items]
Total revenue	47,085	53,478	131,270	142,636
Summit Materials, LLC
Revenue from External Customer [Line Items]
Total revenue	709,619	732,082	1,707,818	1,665,612
Summit Materials, LLC | Aggregates
Revenue from External Customer [Line Items]
Total revenue	136,396	137,528	362,546	354,050
Summit Materials, LLC | Cement
Revenue from External Customer [Line Items]
Total revenue	82,698	92,482	188,854	202,780
Summit Materials, LLC | Ready-mix concrete
Revenue from External Customer [Line Items]
Total revenue	179,124	172,758	488,710	444,258
Summit Materials, LLC | Asphalt
Revenue from External Customer [Line Items]
Total revenue	128,125	137,753	255,992	254,156
Summit Materials, LLC | Paving and related services
Revenue from External Customer [Line Items]
Total revenue	136,191	138,083	280,446	267,732
Summit Materials, LLC | Other
Revenue from External Customer [Line Items]
Total revenue	$ 47,085	$ 53,478	$ 131,270	$ 142,636

REVENUE RECOGNITION - Summary o

REVENUE RECOGNITION - Summary of Accounts Receivable, Net (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Dec. 28, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 231,663	$ 191,672
Construction contract receivables	62,183	47,966
Retention receivables	18,501	17,808
Receivables from related parties	1,918	1,596
Accounts receivable	314,265	259,042
Less: Allowance for doubtful accounts	(4,888)	(5,786)
Accounts receivable, net	$ 309,377	253,256
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
General collection and billing period for retention receivables	1 year
Summit Materials, LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 231,663	191,672
Construction contract receivables	62,183	47,966
Retention receivables	18,501	17,808
Receivables from related parties	1,918	1,596
Accounts receivable	314,265	259,042
Less: Allowance for doubtful accounts	(4,888)	(5,786)
Accounts receivable, net	$ 309,377	$ 253,256
Summit Materials, LLC | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
General collection and billing period for retention receivables	1 year

INVENTORIES - Components of Inv

INVENTORIES - Components of Inventories (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Inventory [Line Items]
Aggregate stockpiles	$ 143,271	$ 140,461
Finished goods	31,657	33,023
Work in process	10,062	7,664
Raw materials	24,784	23,639
Total	209,774	204,787
Summit Materials, LLC
Inventory [Line Items]
Aggregate stockpiles	143,271	140,461
Finished goods	31,657	33,023
Work in process	10,062	7,664
Raw materials	24,784	23,639
Total	$ 209,774	$ 204,787

ACCRUED EXPENSES - Components o

ACCRUED EXPENSES - Components of Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Schedule Of Accrued Expenses [Line Items]
Interest	$ 11,413	$ 26,892
Payroll and benefits	37,862	29,356
Finance lease obligations	24,868	16,007
Insurance	16,888	14,968
Non-income taxes	18,949	7,666
Deferred asset purchase payments	9,686	3,525
Professional fees	788	902
Other	23,610	20,689
Accrued expenses	144,064	120,005
Summit Materials, LLC
Schedule Of Accrued Expenses [Line Items]
Interest	11,413	26,892
Payroll and benefits	37,862	29,356
Finance lease obligations	24,868	16,007
Insurance	16,888	14,968
Non-income taxes	19,180	7,898
Deferred asset purchase payments	9,686	3,525
Professional fees	788	902
Other	23,610	20,689
Accrued expenses	$ 144,295	$ 120,237

DEBT - Schedule of Debt (Detail

DEBT - Schedule of Debt (Details) - USD ($)	Sep. 26, 2020	Dec. 28, 2019	Jun. 01, 2017	Jul. 08, 2015
Debt Instrument [Line Items]
Total debt	$ 1,918,545,000	$ 1,872,273,000
Current portion of debt	7,942,000	7,942,000
Long-term debt	1,910,603,000	1,864,331,000
Gross amount	1,919,491,000
Debt discount	$ 946,000
6 1/8% Senior Notes, due 2023
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	6.125%
5 1/8% Senior Notes, due 2025
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	5.125%
Summit Materials, LLC
Debt Instrument [Line Items]
Total debt	$ 1,918,545,000	1,872,273,000
Current portion of debt	7,942,000	7,942,000
Long-term debt	1,910,603,000	1,864,331,000
Gross amount	1,919,491,000
Debt discount	$ 946,000
Summit Materials, LLC | 6 1/8% Senior Notes, due 2023
Debt Instrument [Line Items]
Debt instrument interest rate (as a percent)	6.125%			6.125%
Summit Materials, LLC | 5 1/8% Senior Notes, due 2025
Debt Instrument [Line Items]
Total debt			$ 300,000,000
Debt instrument interest rate (as a percent)	5.125%		5.125%
Senior Notes | Term Loan, due 2024
Debt Instrument [Line Items]
Total debt	$ 618,545,000	623,140,000
Gross amount	619,500,000	624,300,000
Debt discount	900,000	1,100,000
Senior Notes | 6 1/8% Senior Notes, due 2023
Debt Instrument [Line Items]
Total debt	0	649,133,000
Gross amount		650,000,000
Debt discount		900,000
Senior Notes | 5 1/8% Senior Notes, due 2025
Debt Instrument [Line Items]
Total debt	300,000,000	300,000,000
Senior Notes | 6 1/2% Senior Notes, due 2027
Debt Instrument [Line Items]
Total debt	$ 300,000,000	300,000,000
Debt instrument interest rate (as a percent)	6.50%
Senior Notes | 5 1/4% Senior Notes Due 2029
Debt Instrument [Line Items]
Total debt	$ 700,000,000	0
Debt instrument interest rate (as a percent)	5.25%
Senior Notes | Summit Materials, LLC | Term Loan, due 2024
Debt Instrument [Line Items]
Total debt	$ 618,545,000	623,140,000
Gross amount	619,500,000	624,300,000
Debt discount	900,000	1,100,000
Senior Notes | Summit Materials, LLC | 6 1/8% Senior Notes, due 2023
Debt Instrument [Line Items]
Total debt	0	649,133,000
Gross amount		650,000,000
Debt discount		900,000
Senior Notes | Summit Materials, LLC | 5 1/8% Senior Notes, due 2025
Debt Instrument [Line Items]
Total debt	300,000,000	300,000,000
Senior Notes | Summit Materials, LLC | 6 1/2% Senior Notes, due 2027
Debt Instrument [Line Items]
Total debt	$ 300,000,000	300,000,000
Debt instrument interest rate (as a percent)	6.50%
Senior Notes | Summit Materials, LLC | 5 1/4% Senior Notes Due 2029
Debt Instrument [Line Items]
Total debt	$ 700,000,000	$ 0
Debt instrument interest rate (as a percent)	5.25%

DEBT - Schedule of Contractual

DEBT - Schedule of Contractual Payments of Long-Term Debt (Details) $ in Thousands	Sep. 26, 2020USD ($)
Debt Instrument [Line Items]
2020 (three months)	$ 3,177
2021	6,353
2022	6,354
2023	6,354
2024	597,253
2025	300,000
Thereafter	1,000,000
Total	1,919,491
Less: Original issue net discount	(946)
Less: Capitalized loan costs	(17,391)
Total debt	1,901,154
Summit Materials, LLC
Debt Instrument [Line Items]
2020 (three months)	3,177
2021	6,353
2022	6,354
2023	6,354
2024	597,253
2025	300,000
Thereafter	1,000,000
Total	1,919,491
Less: Original issue net discount	(946)
Less: Capitalized loan costs	(17,391)
Total debt	$ 1,901,154

DEBT - Senior Notes (Details)

DEBT - Senior Notes (Details) - USD ($)	Aug. 11, 2020	Mar. 15, 2019	Jun. 01, 2017	Jul. 08, 2015	Sep. 26, 2020	Sep. 28, 2019	Mar. 30, 2019	Sep. 26, 2020	Sep. 28, 2019	Aug. 31, 2020	Dec. 28, 2019	Jun. 29, 2019
Debt Instrument [Line Items]
Long-term debt					$ 1,918,545,000			$ 1,918,545,000			$ 1,872,273,000
Write off of deferred financing fees								$ 3,338,000	$ 2,851,000
6 1/8% Senior Notes, due 2023
Debt Instrument [Line Items]
Senior notes, interest rate (as a percent)					6.125%			6.125%
5 1/8% Senior Notes, due 2025
Debt Instrument [Line Items]
Senior notes, interest rate (as a percent)					5.125%			5.125%
Issuers | 5 1/4% Senior Notes Due 2029
Debt Instrument [Line Items]
Long-term debt	$ 700,000,000
Senior notes, interest rate (as a percent)	5.25%
Proceeds net of related fees and expenses	$ 690,400,000
Issuers | 6 1/2% Senior Notes, due 2027
Debt Instrument [Line Items]
Long-term debt		$ 300,000,000
Senior notes, interest rate (as a percent)		6.50%
Issuers | 6 1/8% Senior Notes, due 2023
Debt Instrument [Line Items]
Senior notes, interest rate (as a percent)				6.125%						6.125%
Debt instrument, repurchased face amount										$ 650,000,000
Debt instrument redemption charge						$ 4,100,000
Write-off of original issue discount						$ 800,000
Write off of deferred financing fees					$ 3,300,000
Debt instrument, face amount				$ 650,000,000
Issuers | 8 1/2% Senior Notes, due 2022
Debt Instrument [Line Items]
Senior notes, interest rate (as a percent)												8.50%
Debt instrument, repurchased face amount												$ 250,000,000
Debt instrument redemption charge							$ 14,600,000
Write off of deferred financing fees							2,900,000
Debt instrument, prepayment premium							11,700,000
Issuers | 5 1/8% Senior Notes, due 2025
Debt Instrument [Line Items]
Long-term debt			$ 300,000,000
Senior notes, interest rate (as a percent)			5.125%
Percentage of par value of senior notes			100.00%
Proceeds net of related fees and expenses			$ 295,400,000
Issuers | 6 1/8% Senior Notes, due 2023, issued at par
Debt Instrument [Line Items]
Debt instrument, face amount				$ 350,000,000
Issuers | 6 1/8% Senior Notes, due 2023, issued at 99.375% of par
Debt Instrument [Line Items]
Percentage of par value of senior notes				99.375%
Debt instrument, face amount				$ 300,000,000
Summit Materials, LLC
Debt Instrument [Line Items]
Long-term debt					$ 1,918,545,000			$ 1,918,545,000			1,872,273,000
Write off of deferred financing fees								$ 3,338,000	$ 2,851,000
Summit Materials, LLC | 6 1/8% Senior Notes, due 2023
Debt Instrument [Line Items]
Senior notes, interest rate (as a percent)				6.125%	6.125%			6.125%
Debt instrument, face amount				$ 650,000,000
Summit Materials, LLC | 8 1/2% Senior Notes, due 2022
Debt Instrument [Line Items]
Senior notes, interest rate (as a percent)												8.50%
Debt instrument, repurchased face amount												$ 250,000,000
Debt instrument redemption charge							14,600,000
Write off of deferred financing fees							2,900,000
Debt instrument, prepayment premium							$ 11,700,000
Summit Materials, LLC | 5 1/8% Senior Notes, due 2025
Debt Instrument [Line Items]
Long-term debt			$ 300,000,000
Senior notes, interest rate (as a percent)			5.125%		5.125%			5.125%
Senior Notes | 5 1/4% Senior Notes Due 2029
Debt Instrument [Line Items]
Long-term debt					$ 700,000,000			$ 700,000,000			0
Senior notes, interest rate (as a percent)					5.25%			5.25%
Senior Notes | 6 1/2% Senior Notes, due 2027
Debt Instrument [Line Items]
Long-term debt					$ 300,000,000			$ 300,000,000			300,000,000
Senior notes, interest rate (as a percent)					6.50%			6.50%
Senior Notes | 6 1/8% Senior Notes, due 2023
Debt Instrument [Line Items]
Long-term debt					$ 0			$ 0			649,133,000
Senior Notes | 5 1/8% Senior Notes, due 2025
Debt Instrument [Line Items]
Long-term debt					300,000,000			300,000,000			300,000,000
Senior Notes | Issuers | 5 1/4% Senior Notes Due 2029
Debt Instrument [Line Items]
Percentage of par value of senior notes	100.00%
Senior Notes | Issuers | 6 1/2% Senior Notes, due 2027
Debt Instrument [Line Items]
Percentage of par value of senior notes		100.00%
Proceeds net of related fees and expenses		$ 296,300,000
Senior Notes | Summit Materials, LLC | 5 1/4% Senior Notes Due 2029
Debt Instrument [Line Items]
Long-term debt					$ 700,000,000			$ 700,000,000			0
Senior notes, interest rate (as a percent)					5.25%			5.25%
Senior Notes | Summit Materials, LLC | 6 1/2% Senior Notes, due 2027
Debt Instrument [Line Items]
Long-term debt					$ 300,000,000			$ 300,000,000			300,000,000
Senior notes, interest rate (as a percent)					6.50%			6.50%
Senior Notes | Summit Materials, LLC | 6 1/8% Senior Notes, due 2023
Debt Instrument [Line Items]
Long-term debt					$ 0			$ 0			649,133,000
Senior Notes | Summit Materials, LLC | 5 1/8% Senior Notes, due 2025
Debt Instrument [Line Items]
Long-term debt					$ 300,000,000			$ 300,000,000			$ 300,000,000

DEBT - Senior Secured Credit Fa

DEBT - Senior Secured Credit Facilities (Details) - Summit Materials, LLC - USD ($)	Feb. 25, 2019	Sep. 26, 2020	Dec. 28, 2019
Term Loan, due 2024
Debt Instrument [Line Items]
Debt instrument, face amount		$ 650,000,000
Quarterly principal repayments percentage		0.25%
Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 345,000,000	$ 345,000,000
Amount outstanding		0	$ 0
Remaining borrowing capacity		329,100,000
Revolving Credit Facility | Federal funds rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Revolving Credit Facility | LIBOR Plus 1%
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
Percentage added to base rate	1.00%
Revolving Credit Facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	3.00%
Letter of Credit
Debt Instrument [Line Items]
Amount outstanding		$ 15,900,000
Senior Secured Credit Facilities
Debt Instrument [Line Items]
First lien leverage ratio	4.75

DEBT - Summary of Activity for

DEBT - Summary of Activity for Deferred Financing Fees (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
Deferred Finance Costs, Own-share Lending Arrangement, Issuance Costs, Accumulated Amortization [Roll Forward]
Beginning balance	$ 15,436	$ 15,475
Loan origination fees	9,565	6,312
Amortization	(2,499)	(2,668)
Write off of deferred financing fees	(3,338)	(2,851)
Ending balance	19,164	16,268
Summit Materials, LLC
Deferred Finance Costs, Own-share Lending Arrangement, Issuance Costs, Accumulated Amortization [Roll Forward]
Beginning balance	15,436	15,475
Loan origination fees	9,565	6,312
Amortization	(2,499)	(2,668)
Write off of deferred financing fees	(3,338)	(2,851)
Ending balance	$ 19,164	$ 16,268

DEBT - Other (Details)

DEBT - Other (Details) - CAD ($)	Jan. 15, 2015	Sep. 26, 2020	Dec. 28, 2019
Canadian subsidiary credit agreement, Operating activities
Debt Instrument [Line Items]
Revolving credit commitment	$ 6,000,000
Canadian subsidiary credit agreement, Capital equipment
Debt Instrument [Line Items]
Revolving credit commitment	$ 500,000
Basis spread on variable rate	0.90%
Canadian subsidiary credit agreement, Guarantees
Debt Instrument [Line Items]
Revolving credit commitment	$ 300,000
Canadian subsidiary credit agreement
Debt Instrument [Line Items]
Amount outstanding		$ 0	$ 0
Prime rate | Canadian subsidiary credit agreement, Operating activities
Debt Instrument [Line Items]
Basis spread on variable rate	0.20%
Summit Materials, LLC | Canadian subsidiary credit agreement, Operating activities
Debt Instrument [Line Items]
Revolving credit commitment	$ 6,000,000
Summit Materials, LLC | Canadian subsidiary credit agreement, Capital equipment
Debt Instrument [Line Items]
Revolving credit commitment	$ 500,000
Basis spread on variable rate	0.90%
Summit Materials, LLC | Canadian subsidiary credit agreement, Guarantees
Debt Instrument [Line Items]
Revolving credit commitment	$ 300,000
Summit Materials, LLC | Canadian subsidiary credit agreement
Debt Instrument [Line Items]
Amount outstanding		$ 0	$ 0
Summit Materials, LLC | Prime rate | Canadian subsidiary credit agreement, Operating activities
Debt Instrument [Line Items]
Basis spread on variable rate	0.20%

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 26, 2020	Mar. 28, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019
Income Taxes [Line Items]
Income tax (benefit) expense	$ (19,613,000)		$ 45,602,000	$ (25,333,000)	$ 34,272,000
Unrecognized tax benefits, decrease due to CARES Act		$ 9,500,000
Unrecognized tax benefits, decrease due to Tax Cuts and Jobs Act of 2017	32,900,000
Valuation allowance	1,675,000			1,675,000		$ 1,675,000
Income tax provision, interest or penalties recognized	0		0	0	0
Deferred tax asset, Investment in limited partnership	1,200,000			1,200,000
Tax receivable agreement liability	327,957,000			327,957,000		326,965,000
Tax Receivable Agreement
Income Taxes [Line Items]
Tax receivable agreement liability	328,000,000			328,000,000		$ 327,000,000
Summit Holdings LP
Income Taxes [Line Items]
Distributions to LP Unitholders				$ 0	0
Summit Holdings LP | Tax Receivable Agreement
Income Taxes [Line Items]
Percentage of benefits to be paid on tax receivable agreement				85.00%
Summit Materials, LLC
Income Taxes [Line Items]
Income tax (benefit) expense	(5,106,000)		18,757,000	$ (4,877,000)	12,265,000
Income tax provision, interest or penalties recognized	$ 0		$ 0	$ 0	$ 0
Common Class A
Income Taxes [Line Items]
Exchanges during period (in shares)				196,542	107,336

EARNINGS PER SHARE - Schedule o

EARNINGS PER SHARE - Schedule of Basic to Diluted Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Reconciliation of basic to diluted loss per share
Net income attributable to Summit Inc.	$ 90,730	$ 55,757	$ 102,815	$ 23,395
Diluted net income attributable to Summit Inc.	$ 90,730	$ 55,757	$ 102,815	$ 23,395
LP Units
Reconciliation of basic to diluted loss per share
Anti dilutive shares excluded from calculation of earnings per share (in shares)	3,053,115	3,368,058	3,086,819	3,404,231
Time-vesting stock options
Reconciliation of basic to diluted loss per share
Anti dilutive shares excluded from calculation of earnings per share (in shares)	2,095,929	0	2,095,929	0
Warrants
Reconciliation of basic to diluted loss per share
Anti dilutive shares excluded from calculation of earnings per share (in shares)	100,037	0	100,037	100,037
Common Class A
Reconciliation of basic to diluted loss per share
Add: Weighted average shares of Class A stock outstanding (in shares)	114,116,564	112,179,137	113,943,292	112,020,275
Weighted average basic shares outstanding (in shares)	114,116,564	112,179,137	113,943,292	112,020,275
Basic (usd per share)	$ 0.79	$ 0.50	$ 0.90	$ 0.21
Add: warrants (in shares)	0	100,037	0	0
Weighted average dilutive shares outstanding (in shares)	114,472,171	115,505,122	114,457,276	112,497,610
Diluted earnings (loss) per share (usd per share)	$ 0.79	$ 0.48	$ 0.90	$ 0.21
Common Class A | LP Units
Reconciliation of basic to diluted loss per share
Add: share-based payment arrangements (in shares)	0	0	0	0
Common Class A | Time-vesting stock options
Reconciliation of basic to diluted loss per share
Add: share-based payment arrangements (in shares)	0	2,788,221	0	216,165
Common Class A | Add: restricted stock units
Reconciliation of basic to diluted loss per share
Add: share-based payment arrangements (in shares)	263,886	384,571	450,353	222,533
Common Class A | Add: performance stock units
Reconciliation of basic to diluted loss per share
Add: share-based payment arrangements (in shares)	91,721	53,156	63,631	38,637
Restricted Stock
Reconciliation of basic to diluted loss per share
Weighted Average Number of Shares, Restricted Stock	320,343	0	145,155	0
Common Class A And Restricted Stock
Reconciliation of basic to diluted loss per share
Add: Weighted average shares of Class A stock outstanding (in shares)	114,436,907	112,179,137	114,088,447	112,020,275
Weighted average basic shares outstanding (in shares)	114,436,907	112,179,137	114,088,447	112,020,275
Basic (usd per share)	$ 0.79	$ 0.50	$ 0.90	$ 0.21

STOCKHOLDERS' EQUITY_MEMBERS'_3

STOCKHOLDERS' EQUITY/MEMBERS' INTEREST - Equity Offerings (Details) - shares	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019	Dec. 29, 2018
Common Class A
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	113,309,385	111,658,927
Exchanges during period (in shares)	196,542	107,336
Stock option exercises (in shares)	14,404
Other equity transactions (in shares)	603,580	509,735
Ending balance (in shares)	114,123,911	112,275,998
Summit Materials, Inc. and Summit Holdings, LP
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	116,559,042	115,094,445
Exchanges during period (in shares)	0	0
Stock option exercises (in shares)	14,404
Other equity transactions (in shares)	603,580	509,735
Ending balance (in shares)	117,177,026	115,604,180
LP Units | Summit Holdings LP
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Number of LP Units outstanding, beginning balance (in shares)	3,249,657	3,435,518
Number of LP Units exchanged (in shares)	(196,542)	(107,336)
Number of LP Units outstanding, ending balance (in shares)	3,053,115	3,328,182
Summit Holdings LP
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Noncontrolling interest elimination (as a percent)	2.60%		2.80%
Summit Materials Inc
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ownership percentage	97.40%	97.10%	97.20%	97.00%

STOCKHOLDERS' EQUITY_MEMBERS'_4

STOCKHOLDERS' EQUITY/MEMBERS' INTEREST - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
Changes in each component of accumulated other comprehensive loss
Beginning balance	$ 1,444,773	$ 1,342,145
Foreign currency translation adjustment, net of tax	(2,473)	2,364
Loss on cash flow hedges, net of tax		(107)
Ending balance	1,569,496	1,386,778
Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Foreign currency translation adjustment, net of tax	(3,395)	3,263
Loss on cash flow hedges, net of tax		(148)
Change in retirement plans
Changes in each component of accumulated other comprehensive loss
Beginning balance	2,171	3,573
Ending balance	2,171	3,573
Change in retirement plans | Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Beginning balance	(6,317)	(4,392)
Ending balance	(6,317)	(4,392)
Foreign currency translation adjustments
Changes in each component of accumulated other comprehensive loss
Beginning balance	1,277	(2,147)
Foreign currency translation adjustment, net of tax	(2,473)	2,364
Ending balance	(1,196)	217
Foreign currency translation adjustments | Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Beginning balance	(14,654)	(19,370)
Foreign currency translation adjustment, net of tax	(3,395)	3,263
Ending balance	(18,049)	(16,107)
Cash flow hedge adjustments
Changes in each component of accumulated other comprehensive loss
Beginning balance	0	1,255
Loss on cash flow hedges, net of tax		(107)
Ending balance	0	1,148
Cash flow hedge adjustments | Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Beginning balance	0	146
Loss on cash flow hedges, net of tax		(148)
Ending balance	0	(2)
Accumulated other comprehensive income (loss)
Changes in each component of accumulated other comprehensive loss
Beginning balance	3,448	2,681
Ending balance	975	4,938
Accumulated other comprehensive income (loss) | Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Beginning balance	(20,971)	(23,616)
Ending balance	$ (24,366)	$ (20,501)

SUPPLEMENTAL CASH FLOW INFORM_3

SUPPLEMENTAL CASH FLOW INFORMATION - Schedule of Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
Cash payments:
Interest	$ 86,427	$ 89,759
Payments (refunds) for income taxes, net	1,131	(912)
Operating cash payments on operating leases	8,372	8,188
Operating cash payments on finance leases	2,402	2,322
Finance cash payments on finance leases	11,528	9,806
Non cash financing activities:
Right of use assets obtained in exchange for operating lease obligations	2,931	4,387
Right of use assets obtained in exchange for finance leases obligations	17,605	18,586
Exchange of LP Units to shares of Class A common stock	4,648	1,995
Summit Materials, LLC
Cash payments:
Interest	86,427	89,759
Payments (refunds) for income taxes, net	1,131	(912)
Operating cash payments on operating leases	8,372	8,188
Operating cash payments on finance leases	2,402	2,322
Finance cash payments on finance leases	11,528	9,806
Non cash financing activities:
Right of use assets obtained in exchange for operating lease obligations	2,931	4,387
Right of use assets obtained in exchange for finance leases obligations	$ 17,605	$ 18,586

LEASES - Operating and Finance

LEASES - Operating and Finance Leases (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019
Lease, Cost [Abstract]
Operating lease cost	$ 2,478	$ 2,608	$ 7,576	$ 7,757
Variable lease cost	90	151	253	366
Short-term lease cost	14,335	11,871	33,369	28,043
Financing lease cost:
Amortization of right-of-use assets	3,439	2,612	9,307	7,905
Interest on lease liabilities	780	773	2,329	2,404
Total lease cost	21,122	18,015	52,834	46,475
Operating leases:
Operating lease right-of-use assets	28,551		28,551		$ 32,777
Current operating lease liabilities	8,193		8,193		8,427
Noncurrent operating lease liabilities	21,327		21,327		25,381
Total operating lease liabilities	$ 29,520		$ 29,520		33,808
Finance leases:
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization		us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
Property and equipment, gross	$ 92,873		$ 92,873		82,660
Less accumulated depreciation	(29,663)		(29,663)		(24,907)
Property and equipment, net	63,210		63,210		57,753
Current finance lease liabilities	24,868		24,868		16,007
Long-term finance lease liabilities	34,913		34,913		40,410
Total finance lease liabilities	$ 59,781		$ 59,781		$ 56,417
Weighted average remaining lease term (years):
Operating leases	9 years		9 years		8 years 7 months 6 days
Finance lease	2 years 7 months 6 days		2 years 7 months 6 days		2 years 7 months 6 days
Weighted average discount rate (%):
Operating leases	5.40%		5.40%		5.50%
Finance lease	5.20%		5.20%		5.50%
Operating Leases
2020 (three months)	$ 2,444		$ 2,444
2021	8,818		8,818
2022	5,475		5,475
2023	4,243		4,243
2024	2,547		2,547
2025	1,507		1,507
Thereafter	12,808		12,808
Total lease payments	37,842		37,842
Less imputed interest	(8,322)		(8,322)
Finance Leases
2020 (three months)	4,995		4,995
2021	26,169		26,169
2022	18,519		18,519
2023	6,867		6,867
2024	3,207		3,207
2025	2,573		2,573
Thereafter	2,831		2,831
Total lease payments	65,161		65,161
Less imputed interest	(5,380)		(5,380)
Summit Materials, LLC
Lease, Cost [Abstract]
Operating lease cost	2,478	2,608	7,576	7,757
Variable lease cost	90	151	253	366
Short-term lease cost	14,335	11,871	33,369	28,043
Financing lease cost:
Amortization of right-of-use assets	3,439	2,612	9,307	7,905
Interest on lease liabilities	780	773	2,329	2,404
Total lease cost	21,122	$ 18,015	52,834	$ 46,475
Operating leases:
Operating lease right-of-use assets	28,551		28,551		$ 32,777
Current operating lease liabilities	8,193		8,193		8,427
Noncurrent operating lease liabilities	21,327		21,327		25,381
Total operating lease liabilities	$ 29,520		$ 29,520		33,808
Finance leases:
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization		us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
Property and equipment, gross	$ 92,873		$ 92,873		82,660
Less accumulated depreciation	(29,663)		(29,663)		(24,907)
Property and equipment, net	63,210		63,210		57,753
Current finance lease liabilities	24,868		24,868		16,007
Long-term finance lease liabilities	34,913		34,913		40,410
Total finance lease liabilities	$ 59,781		$ 59,781		$ 56,417
Weighted average remaining lease term (years):
Operating leases	9 years		9 years		8 years 7 months 6 days
Finance lease	2 years 7 months 6 days		2 years 7 months 6 days		2 years 7 months 6 days
Weighted average discount rate (%):
Operating leases	5.40%		5.40%		5.50%
Finance lease	5.20%		5.20%		5.50%
Operating Leases
2020 (three months)	$ 2,444		$ 2,444
2021	8,818		8,818
2022	5,475		5,475
2023	4,243		4,243
2024	2,547		2,547
2025	1,507		1,507
Thereafter	12,808		12,808
Total lease payments	37,842		37,842
Less imputed interest	(8,322)		(8,322)
Finance Leases
2020 (three months)	4,995		4,995
2021	26,169		26,169
2022	18,519		18,519
2023	6,867		6,867
2024	3,207		3,207
2025	2,573		2,573
Thereafter	2,831		2,831
Total lease payments	65,161		65,161
Less imputed interest	$ (5,380)		$ (5,380)

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 26, 2020	Dec. 28, 2019
Loss Contingencies [Line Items]
Anticipated costs	$ 106.9	$ 97.4
Term of purchase commitments	1 year
Site Restoration Obligations | Other noncurrent liabilities
Loss Contingencies [Line Items]
Site restoration obligation, non-current	$ 33.2	28.8
Site Restoration Obligations | Accrued expenses.
Loss Contingencies [Line Items]
Site restoration obligation, current	$ 6.9	7.9
Summit Materials, LLC
Loss Contingencies [Line Items]
Term of purchase commitments	1 year
Summit Materials, LLC | Site Restoration Obligations
Loss Contingencies [Line Items]
Anticipated costs	$ 106.9	97.4
Summit Materials, LLC | Site Restoration Obligations | Other noncurrent liabilities
Loss Contingencies [Line Items]
Site restoration obligation, non-current	33.2	28.8
Summit Materials, LLC | Site Restoration Obligations | Accrued expenses.
Loss Contingencies [Line Items]
Site restoration obligation, current	$ 6.9	$ 7.9

FAIR VALUE - Fair Value Measure

FAIR VALUE - Fair Value Measurements (Details) - Level 3 $ in Thousands	9 Months Ended
	Sep. 26, 2020USD ($)	Sep. 28, 2019USD ($)	Dec. 28, 2019USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of acquisition-related liabilities and accrued expenses - contingent consideration	$ 525		$ 1,967
Acquisition-related liabilities and other noncurrent liabilities - contingent consideration	1,303		1,302
Adjustment to contingent consideration	0	$ 0
Summit Materials, LLC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of acquisition-related liabilities and accrued expenses - contingent consideration	525		1,967
Acquisition-related liabilities and other noncurrent liabilities - contingent consideration	1,303		$ 1,302
Adjustment to contingent consideration	$ 0	$ 0
Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration fair value measurement input	0.095
Discount Rate | Summit Materials, LLC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration fair value measurement input	0.095

FAIR VALUE - Carrying Value and

FAIR VALUE - Carrying Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Financial Instruments
Current portion of debt	$ 7,942	$ 7,942
Summit Materials, LLC
Financial Instruments
Current portion of debt	7,942	7,942
Level 2
Financial Instruments
Current portion of debt	7,900	7,900
Level 2 | Fair Value
Financial Instruments
Long-term debt	1,939,247	1,918,720
Level 2 | Carrying Value
Financial Instruments
Long-term debt	1,918,545	1,872,273
Level 2 | Summit Materials, LLC
Financial Instruments
Current portion of debt	7,900	7,900
Level 2 | Summit Materials, LLC | Fair Value
Financial Instruments
Long-term debt	1,939,247	1,918,720
Level 2 | Summit Materials, LLC | Carrying Value
Financial Instruments
Long-term debt	1,918,545	1,872,273
Level 3 | Fair Value
Financial Instruments
Current portion of deferred consideration and noncompete obligations	31,443	30,733
Long term portion of deferred consideration and noncompete obligations	11,573	18,499
Level 3 | Carrying Value
Financial Instruments
Current portion of deferred consideration and noncompete obligations	31,443	30,733
Long term portion of deferred consideration and noncompete obligations	11,573	18,499
Level 3 | Summit Materials, LLC | Fair Value
Financial Instruments
Current portion of deferred consideration and noncompete obligations	29,067	28,233
Long term portion of deferred consideration and noncompete obligations	11,573	16,364
Level 3 | Summit Materials, LLC | Carrying Value
Financial Instruments
Current portion of deferred consideration and noncompete obligations	29,067	28,233
Long term portion of deferred consideration and noncompete obligations	$ 11,573	$ 16,364

SEGMENT INFORMATION - Financial

SEGMENT INFORMATION - Financial Data (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020USD ($)	Sep. 28, 2019USD ($)	Sep. 26, 2020USD ($)segment	Sep. 28, 2019USD ($)	Dec. 28, 2019USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment			3
Number of reportable segments | segment			3
Total revenue	$ 709,619	$ 732,082	$ 1,707,818	$ 1,665,612
Income from operations before taxes	73,156	103,839	79,597	58,998
Interest expense	24,623	28,917	78,049	88,423
Depreciation, depletion and amortization	57,364	54,575	161,912	162,417
Accretion	690	552	1,848	1,723
Loss on debt financings	4,064	0	4,064	14,565
Transaction costs	445	751	1,517	1,449
Non-cash compensation	13,322	4,819	23,119	15,424
Other	4,083	(136)	4,287	(2,628)
Total Adjusted EBITDA	177,747	193,317	354,393	340,371
Total purchases of property, plant and equipment			140,006	139,762
Total depreciation, depletion, amortization and accretion	58,054	55,127	163,760	164,140
Total assets	4,292,170		4,292,170		$ 4,067,556
Operating segment
Segment Reporting Information [Line Items]
Total purchases of property, plant and equipment			138,251	138,596
Total depreciation, depletion, amortization and accretion	57,075	54,086	160,800	161,155
Total assets	3,757,133		3,757,133		3,537,047
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	(9,752)	(8,127)	(25,560)	(20,699)
Total purchases of property, plant and equipment			1,755	1,166
Total depreciation, depletion, amortization and accretion	979	1,041	2,960	2,985
Total assets	535,037		535,037		530,509
West
Segment Reporting Information [Line Items]
Total revenue	390,310	366,504	919,016	848,661
West | Operating segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	95,470	81,936	196,881	151,054
Total purchases of property, plant and equipment			51,148	61,679
Total depreciation, depletion, amortization and accretion	23,117	23,307	67,082	70,156
Total assets	1,540,792		1,540,792		1,379,684
East
Segment Reporting Information [Line Items]
Total revenue	234,435	266,587	590,341	596,107
East | Operating segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	56,943	76,825	119,900	134,479
Total purchases of property, plant and equipment			75,006	61,830
Total depreciation, depletion, amortization and accretion	22,803	19,668	65,293	59,719
Total assets	1,347,883		1,347,883		1,288,835
Cement
Segment Reporting Information [Line Items]
Total revenue	84,874	98,991	198,461	220,844
Cement | Operating segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	35,086	42,683	63,172	75,537
Total purchases of property, plant and equipment			12,097	15,087
Total depreciation, depletion, amortization and accretion	11,155	11,111	28,425	31,280
Total assets	868,458		$ 868,458		868,528
Summit Materials, LLC
Segment Reporting Information [Line Items]
Number of operating segments | segment			3
Number of reportable segments | segment			3
Total revenue	709,619	732,082	$ 1,707,818	1,665,612
Income from operations before taxes	73,218	103,956	79,839	59,401
Interest expense	24,561	28,800	77,807	88,020
Depreciation, depletion and amortization	57,364	54,575	161,912	162,417
Accretion	690	552	1,848	1,723
Loss on debt financings	4,064	0	4,064	14,565
Transaction costs	445	751	1,517	1,449
Non-cash compensation	13,322	4,819	23,119	15,424
Other	4,083	(136)	4,287	(2,628)
Total Adjusted EBITDA	177,747	193,317	354,393	340,371
Total purchases of property, plant and equipment			140,006	139,762
Total depreciation, depletion, amortization and accretion	58,054	55,127	163,760	164,140
Total assets	4,051,270		4,051,270		3,856,223
Summit Materials, LLC | Operating segment
Segment Reporting Information [Line Items]
Total purchases of property, plant and equipment			138,251	138,596
Total depreciation, depletion, amortization and accretion	57,075	54,086	160,800	161,155
Total assets	3,757,133		3,757,133		3,537,047
Summit Materials, LLC | Corporate, Non-Segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	(9,752)	(8,127)	(25,560)	(20,699)
Total purchases of property, plant and equipment			1,755	1,166
Total depreciation, depletion, amortization and accretion	979	1,041	2,960	2,985
Total assets	294,137		294,137		319,176
Summit Materials, LLC | West
Segment Reporting Information [Line Items]
Total revenue	390,310	366,504	919,016	848,661
Summit Materials, LLC | West | Operating segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	95,470	81,936	196,881	151,054
Total purchases of property, plant and equipment			51,148	61,679
Total depreciation, depletion, amortization and accretion	23,117	23,307	67,082	70,156
Total assets	1,540,792		1,540,792		1,379,684
Summit Materials, LLC | East
Segment Reporting Information [Line Items]
Total revenue	234,435	266,587	590,341	596,107
Summit Materials, LLC | East | Operating segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	56,943	76,825	119,900	134,479
Total purchases of property, plant and equipment			75,006	61,830
Total depreciation, depletion, amortization and accretion	22,803	19,668	65,293	59,719
Total assets	1,347,883		1,347,883		1,288,835
Summit Materials, LLC | Cement
Segment Reporting Information [Line Items]
Total revenue	84,874	98,991	198,461	220,844
Summit Materials, LLC | Cement | Operating segment
Segment Reporting Information [Line Items]
Total Adjusted EBITDA	35,086	42,683	63,172	75,537
Total purchases of property, plant and equipment			12,097	15,087
Total depreciation, depletion, amortization and accretion	11,155	$ 11,111	28,425	$ 31,280
Total assets	$ 868,458		$ 868,458		$ 868,528

GUARANTOR AND NON-GUARANTOR F_3

GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - Schedule of Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Jun. 27, 2020	Mar. 28, 2020	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018
Current assets:
Cash and cash equivalents	$ 288,757			$ 311,319
Accounts receivable, net	309,377			253,256
Cost and estimated earnings in excess of billings	44,001			13,088
Inventories	209,774			204,787
Other current assets	13,632			13,831
Total current assets	865,541			796,281
Property, plant and equipment and finance lease right-of-use asset, net	1,763,066			1,747,449
Goodwill	1,303,086			1,199,699
Intangible assets, net	37,923			23,498
Operating lease right-of-use assets	28,551			32,777
Other assets	52,103			55,519
Total assets	4,292,170			4,067,556
Current liabilities:
Current portion of debt	7,942			7,942
Current portion of acquisition-related liabilities	31,968			32,700
Accounts payable	149,475			116,359
Accrued expenses	144,064			120,005
Current operating lease liabilities	8,193			8,427
Billings in excess of costs and estimated earnings	14,225			13,864
Total current liabilities	355,867			299,297
Long-term debt	1,893,212			1,851,057
Acquisition-related liabilities	12,876			19,801
Noncurrent operating lease liabilities	21,327			25,381
Other noncurrent liabilities	111,435			100,282
Total liabilities	2,722,674			2,622,783
Total liabilities and stockholders’ equity/member's interest	4,292,170			4,067,556
Summit Materials, LLC
Current assets:
Cash and cash equivalents	288,757			311,319
Accounts receivable, net	309,377			253,256
Intercompany receivables	0			0
Cost and estimated earnings in excess of billings	44,001			13,088
Inventories	209,774			204,787
Other current assets	13,632			13,831
Total current assets	865,541			796,281
Property, plant and equipment and finance lease right-of-use asset, net	1,763,066			1,747,449
Goodwill	1,304,086			1,200,699
Intangible assets, net	37,923			23,498
Operating lease right-of-use assets	28,551			32,777
Other assets	52,103			55,519
Total assets	4,051,270			3,856,223
Current liabilities:
Current portion of debt	7,942			7,942
Current portion of acquisition-related liabilities	29,592			30,200
Accounts payable	150,086			116,970
Accrued expenses	144,295			120,237
Current operating lease liabilities	8,193			8,427
Intercompany payables	0			0
Billings in excess of costs and estimated earnings	14,225			13,864
Total current liabilities	354,333			297,640
Long-term debt	1,893,212			1,851,057
Acquisition-related liabilities	12,876			17,666
Noncurrent operating lease liabilities	21,327			25,381
Other noncurrent liabilities	155,011			151,329
Total liabilities	2,436,759			2,343,073
Total member's interest	1,614,511	$ 1,520,828	$ 1,442,973	1,513,150	$ 1,450,664	$ 1,360,044	$ 1,299,730	$ 1,385,431
Total liabilities and stockholders’ equity/member's interest	4,051,270			3,856,223
Summit Materials, LLC | Eliminations
Current assets:
Cash and cash equivalents	(4,588)			(6,477)
Accounts receivable, net	(87)			(33)
Intercompany receivables	(1,553,152)			(1,385,708)
Cost and estimated earnings in excess of billings	0			0
Inventories	0			0
Other current assets	0			0
Total current assets	(1,557,827)			(1,392,218)
Property, plant and equipment and finance lease right-of-use asset, net	0			0
Goodwill	0			0
Intangible assets, net	0			0
Operating lease right-of-use assets	0			0
Other assets	(4,068,357)			(3,709,690)
Total assets	(5,626,184)			(5,101,908)
Current liabilities:
Current portion of debt	0			0
Current portion of acquisition-related liabilities	0			0
Accounts payable	(87)			(33)
Accrued expenses	(4,588)			(6,477)
Current operating lease liabilities	0			0
Intercompany payables	(1,553,152)			(1,385,708)
Billings in excess of costs and estimated earnings	0			0
Total current liabilities	(1,557,827)			(1,392,218)
Long-term debt	0			0
Acquisition-related liabilities	0			0
Noncurrent operating lease liabilities	0			0
Other noncurrent liabilities	(164,421)			(137,018)
Total liabilities	(1,722,248)			(1,529,236)
Total member's interest	(3,903,936)			(3,572,672)
Total liabilities and stockholders’ equity/member's interest	(5,626,184)			(5,101,908)
Summit Materials, LLC | Issuers | Reportable Legal Entities
Current assets:
Cash and cash equivalents	277,052			302,474
Accounts receivable, net	1			0
Intercompany receivables	424,533			443,323
Cost and estimated earnings in excess of billings	0			0
Inventories	0			0
Other current assets	2,219			1,763
Total current assets	703,805			747,560
Property, plant and equipment and finance lease right-of-use asset, net	10,383			11,602
Goodwill	0			0
Intangible assets, net	0			0
Operating lease right-of-use assets	2,793			3,316
Other assets	3,922,503			3,596,161
Total assets	4,639,484			4,358,639
Current liabilities:
Current portion of debt	7,942			7,942
Current portion of acquisition-related liabilities	0			0
Accounts payable	5,935			4,588
Accrued expenses	37,693			51,043
Current operating lease liabilities	874			764
Intercompany payables	1,072,127			922,356
Billings in excess of costs and estimated earnings	0			0
Total current liabilities	1,124,571			986,693
Long-term debt	1,893,212			1,851,057
Acquisition-related liabilities	0			0
Noncurrent operating lease liabilities	2,801			3,480
Other noncurrent liabilities	4,389			4,259
Total liabilities	3,024,973			2,845,489
Total member's interest	1,614,511			1,513,150
Total liabilities and stockholders’ equity/member's interest	4,639,484			4,358,639
Summit Materials, LLC | 100% Owned Guarantors | Reportable Legal Entities
Current assets:
Cash and cash equivalents	3,350			5,488
Accounts receivable, net	289,977			234,053
Intercompany receivables	1,128,619			942,385
Cost and estimated earnings in excess of billings	40,711			12,291
Inventories	203,217			199,794
Other current assets	9,724			10,308
Total current assets	1,675,598			1,404,319
Property, plant and equipment and finance lease right-of-use asset, net	1,691,382			1,674,443
Goodwill	1,222,786			1,142,063
Intangible assets, net	37,923			23,498
Operating lease right-of-use assets	21,647			24,551
Other assets	197,286			168,314
Total assets	4,846,622			4,437,188
Current liabilities:
Current portion of debt	0			0
Current portion of acquisition-related liabilities	29,592			30,200
Accounts payable	135,658			103,812
Accrued expenses	105,201			72,970
Current operating lease liabilities	6,239			6,571
Intercompany payables	469,880			447,827
Billings in excess of costs and estimated earnings	13,139			12,183
Total current liabilities	759,709			673,563
Long-term debt	0			0
Acquisition-related liabilities	12,876			17,666
Noncurrent operating lease liabilities	15,600			18,047
Other noncurrent liabilities	207,881			203,919
Total liabilities	996,066			913,195
Total member's interest	3,850,556			3,523,993
Total liabilities and stockholders’ equity/member's interest	4,846,622			4,437,188
Summit Materials, LLC | Non-Guarantors | Reportable Legal Entities
Current assets:
Cash and cash equivalents	12,943			9,834
Accounts receivable, net	19,486			19,236
Intercompany receivables	0			0
Cost and estimated earnings in excess of billings	3,290			797
Inventories	6,557			4,993
Other current assets	1,689			1,760
Total current assets	43,965			36,620
Property, plant and equipment and finance lease right-of-use asset, net	61,301			61,404
Goodwill	81,300			58,636
Intangible assets, net	0			0
Operating lease right-of-use assets	4,111			4,910
Other assets	671			734
Total assets	191,348			162,304
Current liabilities:
Current portion of debt	0			0
Current portion of acquisition-related liabilities	0			0
Accounts payable	8,580			8,603
Accrued expenses	5,989			2,701
Current operating lease liabilities	1,080			1,092
Intercompany payables	11,145			15,525
Billings in excess of costs and estimated earnings	1,086			1,681
Total current liabilities	27,880			29,602
Long-term debt	0			0
Acquisition-related liabilities	0			0
Noncurrent operating lease liabilities	2,926			3,854
Other noncurrent liabilities	107,162			80,169
Total liabilities	137,968			113,625
Total member's interest	53,380			48,679
Total liabilities and stockholders’ equity/member's interest	$ 191,348			$ 162,304

GUARANTOR AND NON-GUARANTOR F_4

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. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Condensed Consolidating Statements of Operations
Revenue	$ 709,619	$ 732,082	$ 1,707,818	$ 1,665,612
Cost of revenue (excluding items shown separately below)	469,004	482,979	1,165,317	1,155,476
Depreciation, depletion, amortization and accretion	58,054	55,127	163,760	164,140
Operating income	100,617	130,881	158,957	153,632
Income from operations before taxes	73,156	103,839	79,597	58,998
Income tax expense (benefit)	(19,613)	45,602	(25,333)	34,272
Net income (loss) attributable to Summit Inc/LLC	90,730	55,757	102,815	23,395
Comprehensive loss attributable to member of Summit Materials, LLC	92,202	54,904	100,342	25,652
Summit Materials, LLC
Condensed Consolidating Statements of Operations
Revenue	709,619	732,082	1,707,818	1,665,612
Cost of revenue (excluding items shown separately below)	469,004	482,979	1,165,317	1,155,476
General and administrative expenses	81,944	63,095	219,784	192,364
Depreciation, depletion, amortization and accretion	58,054	55,127	163,760	164,140
Operating income	100,617	130,881	158,957	153,632
Other (income) loss, net	2,838	(1,875)	1,311	6,211
Interest expense (income)	24,561	28,800	77,807	88,020
Income from operations before taxes	73,218	103,956	79,839	59,401
Income tax expense (benefit)	(5,106)	18,757	(4,877)	12,265
Net income (loss) attributable to Summit Inc/LLC	78,324	85,199	84,716	47,136
Comprehensive loss attributable to member of Summit Materials, LLC	80,342	84,026	81,321	50,251
Summit Materials, LLC | Eliminations
Condensed Consolidating Statements of Operations
Revenue	(4,003)	(4,103)	(13,264)	(8,047)
Cost of revenue (excluding items shown separately below)	(4,003)	(4,103)	(13,264)	(8,047)
General and administrative expenses	0	0	0	0
Depreciation, depletion, amortization and accretion	0	0	0	0
Operating income	0	0	0	0
Other (income) loss, net	138,675	131,665	237,774	197,162
Interest expense (income)	0	0	0	0
Income from operations before taxes	(138,675)	(131,665)	(237,774)	(197,162)
Income tax expense (benefit)	0	0	0	0
Net income (loss) attributable to Summit Inc/LLC	(138,675)	(131,665)	(237,774)	(197,162)
Comprehensive loss attributable to member of Summit Materials, LLC	(136,657)	(132,838)	(241,169)	(194,047)
Issuers | Summit Materials, LLC | Reportable Legal Entities
Condensed Consolidating Statements of Operations
Revenue	0	0	0	0
Cost of revenue (excluding items shown separately below)	0	0	0	0
General and administrative expenses	23,955	13,603	50,964	37,887
Depreciation, depletion, amortization and accretion	980	1,042	2,960	2,986
Operating income	(24,935)	(14,645)	(53,924)	(40,873)
Other (income) loss, net	(134,672)	(132,261)	(235,001)	(183,971)
Interest expense (income)	31,170	32,129	95,379	94,848
Income from operations before taxes	78,567	85,487	85,698	48,250
Income tax expense (benefit)	243	288	982	1,114
Net income (loss) attributable to Summit Inc/LLC	78,324	85,199	84,716	47,136
Comprehensive loss attributable to member of Summit Materials, LLC	80,342	84,026	81,321	50,251
100% Owned Guarantors | Summit Materials, LLC | Reportable Legal Entities
Condensed Consolidating Statements of Operations
Revenue	689,842	706,999	1,659,526	1,603,338
Cost of revenue (excluding items shown separately below)	458,028	467,595	1,138,689	1,114,401
General and administrative expenses	55,242	46,816	160,670	146,136
Depreciation, depletion, amortization and accretion	55,542	52,739	156,697	156,827
Operating income	121,030	139,849	203,470	185,974
Other (income) loss, net	(889)	(1,501)	(1,733)	(6,427)
Interest expense (income)	(7,990)	(4,532)	(21,352)	(10,443)
Income from operations before taxes	129,909	145,882	226,555	202,844
Income tax expense (benefit)	(6,286)	17,325	(7,383)	9,673
Net income (loss) attributable to Summit Inc/LLC	136,195	128,557	233,938	193,171
Comprehensive loss attributable to member of Summit Materials, LLC	136,195	128,402	233,938	193,319
Non-Guarantors | Summit Materials, LLC | Reportable Legal Entities
Condensed Consolidating Statements of Operations
Revenue	23,780	29,186	61,556	70,321
Cost of revenue (excluding items shown separately below)	14,979	19,487	39,892	49,122
General and administrative expenses	2,747	2,676	8,150	8,341
Depreciation, depletion, amortization and accretion	1,532	1,346	4,103	4,327
Operating income	4,522	5,677	9,411	8,531
Other (income) loss, net	(276)	222	271	(553)
Interest expense (income)	1,381	1,203	3,780	3,615
Income from operations before taxes	3,417	4,252	5,360	5,469
Income tax expense (benefit)	937	1,144	1,524	1,478
Net income (loss) attributable to Summit Inc/LLC	2,480	3,108	3,836	3,991
Comprehensive loss attributable to member of Summit Materials, LLC	$ 462	$ 4,436	$ 7,231	$ 728

GUARANTOR AND NON-GUARANTOR F_5

GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION - Schedule of Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
Condensed Consolidating Statements of Operations
Net cash (used in) provided by operating activities	$ 218,039	$ 163,843
Cash flow from investing activities:
Acquisitions, net of cash acquired	(123,195)	(2,842)
Purchase of property, plant and equipment	(140,006)	(139,762)
Proceeds from the sale of property, plant, and equipment	8,848	13,035
Other	1,395	(207)
Net cash used for investing activities	(252,958)	(129,776)
Cash flow from financing activities:
Net proceeds from debt issuance	700,000	300,000
Payments on long-term debt	(666,892)	(264,906)
Payments on acquisition-related liabilities	(10,391)	(11,000)
Debt issuance costs	9,565	6,312
Debt issuance costs	(9,565)	(6,312)
Other	(908)	(501)
Net cash provided by financing activities	12,573	19,840
Impact of foreign currency on cash	(216)	174
Net (decrease) increase in cash	(22,562)	54,081
Cash and cash equivalents—beginning of period	311,319	128,508
Cash and cash equivalents—end of period	288,757	182,589
Summit Materials, LLC
Condensed Consolidating Statements of Operations
Net cash (used in) provided by operating activities	218,039	163,843
Cash flow from investing activities:
Acquisitions, net of cash acquired	(123,195)	(2,842)
Purchase of property, plant and equipment	(140,006)	(139,762)
Proceeds from the sale of property, plant, and equipment	8,848	13,035
Other	1,395	(207)
Net cash used for investing activities	(252,958)	(129,776)
Cash flow from financing activities:
Proceeds from investment by member	329	2,559
Net proceeds from debt issuance	700,000	300,000
Loans received from and payments made on loans from other Summit Companies	0	0
Payments on long-term debt	(666,892)	(264,906)
Payments on acquisition-related liabilities	(7,891)	(8,500)
Debt issuance costs	9,565	6,312
Debt issuance costs	(9,565)	(6,312)
Distributions from partnership	(2,500)	(2,500)
Other	(908)	(501)
Net cash provided by financing activities	12,573	19,840
Impact of foreign currency on cash	(216)	174
Net (decrease) increase in cash	(22,562)	54,081
Cash and cash equivalents—beginning of period	311,319	128,508
Cash and cash equivalents—end of period	288,757	182,589
Summit Materials, LLC | Eliminations
Condensed Consolidating Statements of Operations
Net cash (used in) provided by operating activities	0	0
Cash flow from investing activities:
Acquisitions, net of cash acquired	0	0
Purchase of property, plant and equipment	0	0
Proceeds from the sale of property, plant, and equipment	0	0
Other	0	0
Net cash used for investing activities	0	0
Cash flow from financing activities:
Proceeds from investment by member	0	0
Net proceeds from debt issuance	0	0
Loans received from and payments made on loans from other Summit Companies	1,889	(49)
Payments on long-term debt	0	0
Payments on acquisition-related liabilities	0	0
Debt issuance costs	0
Debt issuance costs		0
Distributions from partnership	0	0
Other	0	0
Net cash provided by financing activities	1,889	(49)
Impact of foreign currency on cash	0	0
Net (decrease) increase in cash	1,889	(49)
Cash and cash equivalents—beginning of period	(6,477)	(4,870)
Cash and cash equivalents—end of period	(4,588)	(4,919)
Summit Materials, LLC | Issuers | Reportable Legal Entities
Condensed Consolidating Statements of Operations
Net cash (used in) provided by operating activities	(110,054)	(85,516)
Cash flow from investing activities:
Acquisitions, net of cash acquired	0	0
Purchase of property, plant and equipment	(1,755)	(1,166)
Proceeds from the sale of property, plant, and equipment	0	0
Other	0	0
Net cash used for investing activities	(1,755)	(1,166)
Cash flow from financing activities:
Proceeds from investment by member	(91,856)	(35,581)
Net proceeds from debt issuance	700,000	300,000
Loans received from and payments made on loans from other Summit Companies	145,896	147,325
Payments on long-term debt	(654,765)	(254,765)
Payments on acquisition-related liabilities	0	0
Debt issuance costs	9,565
Debt issuance costs		(6,312)
Distributions from partnership	(2,500)	(2,500)
Other	(823)	(462)
Net cash provided by financing activities	86,387	147,705
Impact of foreign currency on cash	0	0
Net (decrease) increase in cash	(25,422)	61,023
Cash and cash equivalents—beginning of period	302,474	117,219
Cash and cash equivalents—end of period	277,052	178,242
Summit Materials, LLC | 100% Owned Guarantors | Reportable Legal Entities
Condensed Consolidating Statements of Operations
Net cash (used in) provided by operating activities	288,198	241,172
Cash flow from investing activities:
Acquisitions, net of cash acquired	(92,085)	(2,842)
Purchase of property, plant and equipment	(136,670)	(129,170)
Proceeds from the sale of property, plant, and equipment	8,708	12,950
Other	1,395	(207)
Net cash used for investing activities	(218,652)	(119,269)
Cash flow from financing activities:
Proceeds from investment by member	87,925	38,140
Net proceeds from debt issuance	0	0
Loans received from and payments made on loans from other Summit Companies	(139,650)	(147,782)
Payments on long-term debt	(11,983)	(9,965)
Payments on acquisition-related liabilities	(7,891)	(8,500)
Debt issuance costs	0
Debt issuance costs		0
Distributions from partnership	0	0
Other	(85)	(39)
Net cash provided by financing activities	(71,684)	(128,146)
Impact of foreign currency on cash	0	0
Net (decrease) increase in cash	(2,138)	(6,243)
Cash and cash equivalents—beginning of period	5,488	8,440
Cash and cash equivalents—end of period	3,350	2,197
Summit Materials, LLC | Non-Guarantors | Reportable Legal Entities
Condensed Consolidating Statements of Operations
Net cash (used in) provided by operating activities	39,895	8,187
Cash flow from investing activities:
Acquisitions, net of cash acquired	(31,110)	0
Purchase of property, plant and equipment	(1,581)	(9,426)
Proceeds from the sale of property, plant, and equipment	140	85
Other	0	0
Net cash used for investing activities	(32,551)	(9,341)
Cash flow from financing activities:
Proceeds from investment by member	4,260	0
Net proceeds from debt issuance	0	0
Loans received from and payments made on loans from other Summit Companies	(8,135)	506
Payments on long-term debt	(144)	(176)
Payments on acquisition-related liabilities	0	0
Debt issuance costs	0
Debt issuance costs		0
Distributions from partnership	0	0
Other	0	0
Net cash provided by financing activities	(4,019)	330
Impact of foreign currency on cash	(216)	174
Net (decrease) increase in cash	3,109	(650)
Cash and cash equivalents—beginning of period	9,834	7,719
Cash and cash equivalents—end of period	$ 12,943	$ 7,069