Summit Materials (SUM) 10-K 5 Feb 20 2019 FY Annual report Financial data

Cover

Cover - USD ($) $ in Billions	12 Months Ended
	Dec. 28, 2019	Feb. 03, 2020	Jun. 28, 2019
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 28, 2019
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 Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
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 Public Float			$ 2.2
Documents Incorporated by Reference	Certain information required by Items 10, 11, 12, 13 and 14 of Part III incorporate information by reference from Summit Materials, Inc.’s definitive proxy statement relating to its 2020 annual meeting of stockholders to be filed with the Securities and Exchange Commission within 120 days after the close of Summit Materials, Inc.’s fiscal year.
Entity Central Index Key	0001621563
Amendment Flag	false
Current Fiscal Year End Date	--12-28
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Common Class A
Document Information [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		113,311,347
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 Well-known Seasoned Issuer	No
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	2019
Document Fiscal Period Focus	FY

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Current assets:
Cash and cash equivalents	$ 311,319	$ 128,508
Accounts receivable, net	253,256	214,518
Costs and estimated earnings in excess of billings	13,088	18,602
Inventories	204,787	213,851
Other current assets	13,831	16,061
Total current assets	796,281	591,540
Property, plant and equipment	1,747,449
Property, plant and equipment		1,780,132
Goodwill	1,199,699	1,192,028
Intangible assets	23,498	18,460
Deferred tax assets	212,333	225,397
Operating lease right-of-use assets	32,777
Other assets	55,519	50,084
Total assets	4,067,556	3,857,641
Current liabilities:
Current portion of debt	7,942	6,354
Current portion of acquisition-related liabilities	32,700	34,270
Accounts payable	116,359	107,702
Accrued expenses	120,005	100,491
Current operating lease liabilities	8,427
Billings in excess of costs and estimated earnings	13,864	11,840
Total current liabilities	299,297	260,657
Long-term debt	1,851,057	1,807,502
Acquisition-related liabilities	19,801	49,468
Tax receivable agreement liability	326,965	309,674
Noncurrent operating lease liabilities	25,381
Other noncurrent liabilities	100,282	88,195
Total liabilities	2,622,783	2,515,496
Commitments and contingencies (see note 16)
Stockholders' equity / Member's interest
Additional paid-in capital	1,234,020	1,194,204
Accumulated earnings	188,805	129,739
Accumulated other comprehensive income	3,448	2,681
Stockholders’ equity	1,427,407	1,327,741
Noncontrolling interest in Summit Holdings	17,366	14,404
Total stockholders’ equity	1,444,773	1,342,145
Total liabilities and stockholders' equity / member's interest	4,067,556	3,857,641
Common Class A
Stockholders' equity / Member's interest
Common stock	1,134	1,117
Common Class B
Stockholders' equity / Member's interest
Common stock	0	0
Summit Materials, LLC
Current assets:
Cash and cash equivalents	311,319	128,508
Accounts receivable, net	253,256	214,518
Costs and estimated earnings in excess of billings	13,088	18,602
Inventories	204,787	213,851
Other current assets	13,831	16,061
Total current assets	796,281	591,540
Property, plant and equipment	1,747,449
Property, plant and equipment		1,780,132
Goodwill	1,200,699	1,193,028
Intangible assets	23,498	18,460
Operating lease right-of-use assets	32,777
Other assets	55,519	50,084
Total assets	3,856,223	3,633,244
Current liabilities:
Current portion of debt	7,942	6,354
Current portion of acquisition-related liabilities	30,200	31,770
Accounts payable	116,970	109,008
Accrued expenses	120,237	100,029
Current operating lease liabilities	8,427
Billings in excess of costs and estimated earnings	13,864	11,840
Total current liabilities	297,640	259,001
Long-term debt	1,851,057	1,807,502
Acquisition-related liabilities	17,666	45,354
Noncurrent operating lease liabilities	25,381
Other noncurrent liabilities	151,329	135,956
Total liabilities	2,343,073	2,247,813
Commitments and contingencies (see note 16)
Stockholders' equity / Member's interest
Member's equity	1,432,718	1,396,241
Accumulated earnings	101,403	12,806
Accumulated other comprehensive income	(20,971)	(23,616)
Total member's interest	1,513,150	1,385,431
Total liabilities and stockholders' equity / member's interest	$ 3,856,223	$ 3,633,244

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Common stock, shares authorized (in shares)	1,000,000,000
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)	113,309,385	111,658,927	110,350,594
Common stock, shares outstanding (in shares)	113,309,385	111,658,927
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

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Revenue:
Revenue	$ 2,222,140	$ 2,101,002	$ 1,932,575
Cost of revenue (excluding items shown separately below):
Cost of revenue	1,526,332	1,475,779	1,281,777
General and administrative expenses	262,926	253,609	242,670
Depreciation, depletion, amortization and accretion	217,102	204,910	179,518
Transaction costs	2,222	4,238	7,733
Operating income	213,558	162,466	220,877
Interest expense	116,509	116,548	108,549
Loss on debt financings	14,565	149	4,815
Tax receivable agreement expense (benefit)	16,237	(22,684)	271,016
Gain on sale of business	0	(12,108)	0
Other income, net	(11,977)	(15,516)	(5,303)
Income (loss) from operations before taxes	78,224	96,077	(158,200)
Income tax expense (benefit)	17,101	59,747	(283,977)
Net income	61,123	36,330	125,777
Net income attributable to noncontrolling interest in subsidiaries	0	0	(27)
Net income attributable to Summit Holdings	2,057	2,424	3,974
Net income attributable to Summit Inc.	59,066	33,906	121,830
Summit Materials, LLC
Revenue:
Revenue	2,222,140	2,101,002	1,932,575
Cost of revenue (excluding items shown separately below):
Cost of revenue	1,526,332	1,475,779	1,281,777
General and administrative expenses	262,926	253,609	242,670
Depreciation, depletion, amortization and accretion	217,102	204,910	179,518
Transaction costs	2,222	4,238	7,733
Operating income	213,558	162,466	220,877
Interest expense	115,988	115,831	107,655
Loss on debt financings	14,565	149	4,815
Gain on sale of business	0	(12,108)	0
Other income, net	(11,977)	(15,516)	(5,289)
Income (loss) from operations before taxes	94,982	74,110	113,696
Income tax expense (benefit)	6,385	10,273	(20,345)
Net income	88,597	63,837	134,041
Net income attributable to noncontrolling interest	0	0	(27)
Net income attributable to Summit Inc.	$ 88,597	$ 63,837	$ 134,068
Common Class A
Income per share of Class A common stock:
Basic (USD per share)	$ 0.53	$ 0.30	$ 1.12
Diluted (USD per share)	$ 0.52	$ 0.30	$ 1.11
Weighted average shares of Class A common stock:
Basic (in shares)	112,204,067	111,380,175	108,696,438
Diluted (in shares)	112,684,718	112,316,646	109,490,898
Product
Revenue:
Revenue	$ 1,724,462	$ 1,600,159	$ 1,449,936
Cost of revenue (excluding items shown separately below):
Cost of revenue	1,116,662	1,058,544	898,281
Product | Summit Materials, LLC
Revenue:
Revenue	1,724,462	1,600,159	1,449,936
Cost of revenue (excluding items shown separately below):
Cost of revenue	1,116,662	1,058,544	898,281
Service
Revenue:
Revenue	306,185	309,099	302,473
Cost of revenue (excluding items shown separately below):
Cost of revenue	218,177	225,491	203,330
Service | Summit Materials, LLC
Revenue:
Revenue	306,185	309,099	302,473
Cost of revenue (excluding items shown separately below):
Cost of revenue	218,177	225,491	203,330
Excluding delivery and subcontract revenue
Revenue:
Revenue	2,030,647	1,909,258	1,752,409
Cost of revenue (excluding items shown separately below):
Cost of revenue	1,334,839	1,284,035	1,101,611
Excluding delivery and subcontract revenue | Summit Materials, LLC
Revenue:
Revenue	2,030,647	1,909,258	1,752,409
Cost of revenue (excluding items shown separately below):
Cost of revenue	1,334,839	1,284,035	1,101,611
Delivery and subcontract revenue
Revenue:
Revenue	191,493	191,744	180,166
Cost of revenue (excluding items shown separately below):
Cost of revenue	191,493	191,744	180,166
Delivery and subcontract revenue | Summit Materials, LLC
Revenue:
Revenue	191,493	191,744	180,166
Cost of revenue (excluding items shown separately below):
Cost of revenue	$ 191,493	$ 191,744	$ 180,166

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Net income	$ 61,123	$ 36,330	$ 125,777
Other comprehensive income (loss):
Postretirement curtailment adjustment	0	0	429
Postretirement liability adjustment	(1,925)	1,661	699
Foreign currency translation adjustment	4,716	(9,348)	7,768
Income (loss) on cash flow hedges	(146)
Income (loss) on cash flow hedges		1,206	1,413
Less tax effect of other comprehensive income items	0	1,578	(288)
Other comprehensive income (loss)	2,645	(4,903)	10,021
Comprehensive income	63,768	31,427	135,798
Less comprehensive income attributable to the noncontrolling interest in consolidated subsidiaries	0	0	(27)
Less comprehensive income attributable to Summit Holdings	3,935	2,226	4,360
Comprehensive income attributable to Summit Materials, Inc. / Summit Materials, LLC	59,833	29,201	131,465
Summit Materials, LLC
Net income	88,597	63,837	134,041
Other comprehensive income (loss):
Postretirement curtailment adjustment	0	0	429
Postretirement liability adjustment	(1,925)	1,661	699
Foreign currency translation adjustment	4,716	(9,348)	7,768
Income (loss) on cash flow hedges	(146)
Income (loss) on cash flow hedges		1,206	1,413
Other comprehensive income (loss)	2,645	(6,481)	10,309
Comprehensive income	91,242	57,356	144,350
Less comprehensive income attributable to the noncontrolling interest in consolidated subsidiaries	0	0	(27)
Comprehensive income attributable to Summit Materials, Inc. / Summit Materials, LLC	$ 91,242	$ 57,356	$ 144,377

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Cash flow from operating activities:
Net income	$ 61,123	$ 36,330	$ 125,777
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, amortization and accretion	222,862	208,772	193,107
Share-based compensation expense	20,403	25,378	21,140
Net gain on asset disposals	(10,294)	(30,093)	(7,638)
Non-cash loss on debt financings	2,850	0	3,856
Change in deferred tax asset, net	16,012	57,490	(289,219)
Other	(2,135)	2,018	(2,359)
(Increase) decrease in operating assets, net of acquisitions and dispositions:
Accounts receivable, net	(37,049)	(5,796)	(3,720)
Inventories	8,582	(11,598)	(18,609)
Costs and estimated earnings in excess of billings	5,558	(8,702)	(1,825)
Other current assets	5,465	(7,159)	8,703
Other assets	5,085	(106)	(3,103)
(Decrease) increase in operating liabilities, net of acquisitions and dispositions:
Accounts payable	18,903	(13,403)	6,192
Accrued expenses	7,640	(16,544)	(7,006)
Billings in excess of costs and estimated earnings	1,988	(5,052)	109
Tax receivable agreement liability	17,291	(21,666)	273,194
Other liabilities	(7,100)	(501)	(6,416)
Net cash provided by operating activities	337,184	209,368	292,183
Cash flow from investing activities:
Acquisitions, net of cash acquired	(5,392)	(246,017)	(374,930)
Purchases of property, plant and equipment	(177,495)	(220,685)	(194,146)
Proceeds from the sale of property, plant and equipment	21,173	21,635	17,072
Proceeds from sale of business	0	21,564	0
Other	(1,095)	3,804	(471)
Net cash used for investing activities	(162,809)	(419,699)	(552,475)
Cash flow from financing activities:
Proceeds from equity offerings	0	0	237,600
Capital issuance costs	0	0	(627)
Proceeds from debt issuances	300,000	64,500	302,000
Debt issuance costs	(6,312)	(550)	(6,416)
Payments on debt	(270,229)	(85,042)	(16,438)
Purchase of noncontrolling interests	0	0	(532)
Payments on acquisition-related liabilities	(33,883)	(36,504)	(34,650)
Distributions from partnership	0	(69)	(1,974)
Proceeds from stock option exercises	19,076	15,615	21,661
Other	(502)	(1,943)	(869)
Net cash provided by (used in) financing activities	8,150	(43,993)	499,755
Impact of foreign currency on cash	286	(724)	701
Net increase (decrease) in cash	182,811	(255,048)	240,164
Cash and cash equivalents—beginning of period	128,508	383,556	143,392
Cash and cash equivalents—end of period	311,319	128,508	383,556
Summit Materials, LLC
Cash flow from operating activities:
Net income	88,597	63,837	134,041
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, amortization and accretion	222,341	208,055	192,213
Share-based compensation expense	20,403	25,378	21,140
Net gain on asset disposals	(10,294)	(30,093)	(7,638)
Non-cash loss on debt financings	2,850	0	3,856
Change in deferred tax asset, net	6,350	9,729	(23,070)
Other	(2,135)	2,018	(2,359)
(Increase) decrease in operating assets, net of acquisitions and dispositions:
Accounts receivable, net	(37,049)	(5,796)	(3,720)
Inventories	8,582	(11,598)	(18,609)
Costs and estimated earnings in excess of billings	5,558	(8,702)	(1,825)
Other current assets	5,465	(7,159)	8,703
Other assets	5,085	(106)	(3,103)
(Decrease) increase in operating liabilities, net of acquisitions and dispositions:
Accounts payable	18,208	(13,989)	8,040
Accrued expenses	8,335	(16,653)	(6,230)
Billings in excess of costs and estimated earnings	1,988	(5,052)	109
Other liabilities	(7,100)	(501)	(6,416)
Net cash provided by operating activities	337,184	209,368	295,132
Cash flow from investing activities:
Acquisitions, net of cash acquired	(5,392)	(246,017)	(374,930)
Purchases of property, plant and equipment	(177,495)	(220,685)	(194,146)
Proceeds from the sale of property, plant and equipment	21,173	21,635	17,072
Proceeds from sale of business	0	21,564	0
Other	(1,095)	3,804	(471)
Net cash used for investing activities	(162,809)	(419,699)	(552,475)
Cash flow from financing activities:
Capital contributions by member	19,076	15,615	304,541
Capital issuance costs	0	0	(627)
Proceeds from debt issuances	300,000	64,500	302,000
Debt issuance costs	(6,312)	(550)	(6,416)
Payments on debt	(270,229)	(85,042)	(16,438)
Purchase of noncontrolling interests	0	0	(532)
Payments on acquisition-related liabilities	(31,383)	(34,004)	(32,150)
Distributions from partnership	(2,500)	(2,569)	(51,986)
Other	(502)	(1,943)	(866)
Net cash provided by (used in) financing activities	8,150	(43,993)	497,526
Impact of foreign currency on cash	286	(724)	701
Net increase (decrease) in cash	182,811	(255,048)	240,884
Cash and cash equivalents—beginning of period	128,508	383,556	142,672
Cash and cash equivalents—end of period	$ 311,319	$ 128,508	$ 383,556

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity / Member's Interest and Redeemable Noncontrolling Interest - USD ($) $ in Thousands	Total	Common Class A	Common Class B	Noncontrolling Interest in subsidiaries	Accumulated Earnings/Deficit	Accumulated Other Comprehensive Income (Loss)	Common StockCommon Class A	Common StockCommon Class B	Additional Paid-in Capital	Noncontrolling Interest	Summit Materials, LLC	Summit Materials, LLCMembers' equity	Summit Materials, LLCAccumulated Earnings/Deficit	Summit Materials, LLCAccumulated Other Comprehensive Income (Loss)	Summit Materials, LLCNoncontrolling Interest
Beginning balance stockholders' equity at Dec. 31, 2016	$ 860,039			$ 1,378	$ 19,028	$ (2,249)	$ 961	$ 0	$ 824,304	$ 16,617
Beginning balance stockholders' equity (in shares) at Dec. 31, 2016							96,033,222	100
Beginning balance members' interest at Dec. 31, 2016											$ 876,393	$ 1,087,558	$ (185,099)	$ (27,444)	$ 1,378
Increase (Decrease) In Stockholders' Equity [Rollforward]
Net contributed capital											303,914	303,914
Net (loss) income	125,777			(27)	121,830					3,974	134,041		134,068		(27)
Issuance of shares (in shares)							10,000,000
Issuance of shares	236,971						$ 100		238,367	(1,496)
LP Unit exchanges (in shares)							1,461,677
LP Unit exchanges	0						$ 15		4,159	(4,174)
Other comprehensive income (loss), net of tax	10,021					9,635				386	10,309			10,309
Distributions											(51,986)	(51,986)
Stock option exercises (in shares)							1,203,121
Stock option exercises	21,661						$ 12		21,649
Share-based compensation	21,140								21,140		21,140	21,140
Dividend	(2)				(45,025)		$ 15		45,163	(155)
Dividend (in shares)							1,521,056
Distributions from partnership	(1,974)									(1,974)
Purchase of noncontrolling interest	(1,148)			$ (1,148)							(1,148)				(1,148)
Shares redeemed to settle taxes and other (in shares)				(203,000)			131,518
Shares redeemed to settle taxes and other	(764)						$ 1		(562)		(1,069)	(866)			(203)
Ending balance stockholders' equity at Dec. 30, 2017	1,271,721			$ 0	95,833	7,386	$ 1,104	$ 0	1,154,220	13,178				(17,135)
Ending balance stockholders' equity (in shares) at Dec. 30, 2017		110,350,594					110,350,594	100
Ending balance members' interest at Dec. 30, 2017											1,291,594	1,359,760	(51,031)	(17,135)	0
Increase (Decrease) In Stockholders' Equity [Rollforward]
Net contributed capital											15,615	15,615
Net (loss) income	36,330			0	33,906					2,424	63,837		63,837
LP Unit exchanges (in shares)		254,102					254,102
LP Unit exchanges	0						$ 2		929	(931)
Other comprehensive income (loss), net of tax	$ (4,903)					(4,705)				(198)	(6,481)			(6,481)
Distributions											(2,569)	(2,569)
Stock option exercises (in shares)	863,898	863,898					863,898
Stock option exercises	$ 15,616						$ 9		15,607
Share-based compensation	25,378								25,378		25,378	25,378
Distributions from partnership	(69)									(69)
Shares redeemed to settle taxes and other (in shares)		190,333					190,333	(1)
Shares redeemed to settle taxes and other	(1,928)						$ 2		(1,930)		(1,943)	(1,943)
Ending balance stockholders' equity at Dec. 29, 2018	1,342,145			0	129,739	2,681	$ 1,117	$ 0	1,194,204	14,404				(23,616)
Ending balance stockholders' equity (in shares) at Dec. 29, 2018		111,658,927	99				111,658,927	99
Ending balance members' interest at Dec. 29, 2018											1,385,431	1,396,241	12,806	(23,616)	0
Increase (Decrease) In Stockholders' Equity [Rollforward]
Net contributed capital											19,076	19,076
Net (loss) income	61,123				59,066					2,057	88,597		88,597
LP Unit exchanges (in shares)		185,861					185,861
LP Unit exchanges	0						$ 2		971	(973)
Other comprehensive income (loss), net of tax	$ 2,645					767				1,878	2,645			2,645
Distributions											(2,500)	(2,500)
Stock option exercises (in shares)	1,065,446	1,065,446					1,065,446
Stock option exercises	$ 19,076						$ 11		19,065
Share-based compensation	20,403								20,403		20,403	20,403
Shares redeemed to settle taxes and other (in shares)		399,151					399,151
Shares redeemed to settle taxes and other	(619)						$ 4		(623)		(502)	(502)
Ending balance stockholders' equity at Dec. 28, 2019	$ 1,444,773			$ 0	$ 188,805	$ 3,448	$ 1,134	$ 0	$ 1,234,020	$ 17,366				(20,971)
Ending balance stockholders' equity (in shares) at Dec. 28, 2019		113,309,385	99				113,309,385	99
Ending balance members' interest at Dec. 28, 2019											$ 1,513,150	$ 1,432,718	$ 101,403	$ (20,971)	$ 0

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Redeemable Noncontrolling Interest and Stockholders' Equity / Member's Interest and Redeemable Noncontrolling Interest (Parenthetical)	12 Months Ended
	Dec. 30, 2017$ / shares
Statement of Stockholders' Equity [Abstract]
Dividends (in dollars per share)	$ 0.014

Summary of Organization and Sig

Summary of Organization and Significant Accounting Policies	12 Months Ended
	Dec. 28, 2019
Company Information
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. On September 23, 2014, Summit Inc. was formed as a Delaware corporation to be a holding company. Its sole material asset is a controlling equity interest in Summit Materials Holdings L.P. (“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 ("IPO"), Summit Inc. became a holding corporation operating and controlling all of the business and affairs of Summit Holdings and its subsidiaries. Summit Inc. owns the majority of the partnership interests of Summit Holdings (see note 11, Stockholders’ Equity). Summit Materials, LLC (“Summit LLC”) an indirect wholly owned subsidiary of Summit Holdings, conducts the majority of our operations. Continental Cement Company, L.L.C. (“Continental Cement”) is also a wholly owned subsidiary of Summit LLC. Summit Materials Finance Corp. (“Summit Finance”), an indirect wholly owned subsidiary of Summit LLC, has jointly issued our Senior Notes as described below. 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. As a result of the Reorganization, Summit Holdings became a variable interest entity over which Summit Inc. has 100% voting power and control and for which Summit Inc. has the obligation to absorb losses and the right to receive benefits. The Company’s fiscal year is based on a 52-53 week year with each quarter composed of 13 weeks ending on a Saturday. The 53-week year last occurred in 2015, and will occur in 2020. For a summary of the changes in Summit Inc.’s ownership of Summit Holdings, see Note 11, Stockholders’ Equity. The Company attributes consolidated stockholders’ equity and net income separately to the controlling and noncontrolling interests. The Company accounts for investments in entities for which it has an ownership of 20% to 50% using the equity method of accounting. Use of Estimates —Preparation of these consolidated financial statements in conformity with U.S. generally accepted accounting principles (“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, the 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, Utah, Kansas 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 2019 , 2018 or 2017 . Accounts Receivable —Accounts receivable are stated at the amount management expects to collect from outstanding balances. Management provides for probable uncollectible amounts through a charge to earnings and a credit to a valuation allowance based on its assessment of the collectability of individual accounts. In establishing the allowance, management considers historical losses adjusted to take into account current market conditions and its customers’ financial condition, the amount of receivables in dispute, the current receivables aging and current payment terms. Balances that remain outstanding after reasonable collection efforts are exercised are written off through a charge to the valuation allowance. The balances billed but not paid by customers, pursuant to retainage provisions included in contracts, are generally due upon completion of the contracts. 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 plastics components, and from the provision of services, which are primarily paving and related services, but also include landfill operations, the receipt and disposal of waste that is converted to fuel for use in our cement plants. Products We earn revenue from the sale of products, which primarily include aggregates, cement, ready-mix concrete and asphalt, but also include concrete products, net of discounts or allowances, if any, and freight and delivery charges billed to customers. Freight and delivery charges associated with cement sales are recorded on a net basis together with freight costs within cost of sales. Revenue for product sales is recognized when evidence of an arrangement exists and when control passes, which generally is when the product is shipped. Aggregates and cement products are sold point-of-sale through purchase orders. When the product is sold on account, collectability typically occurs 30 to 60 days after the sale. Revenue is recognized when cash is received from the customer at the point of sale or when the products are delivered or collected on site. There are no other timing implications that will create a contract asset or liability, and contract modifications are unlikely given the timing and nature of the transaction. Material sales are likely to have multiple performance obligations if the product is sold with delivery. In these instances, delivery most often occurs on the same day as the control of the product transfers to the customer. As a result, even in the case of multiple performance obligations, the performance obligations are satisfied concurrently and revenue is recognized simultaneously. Services We earn revenue from the provision of services, which are primarily paving and related services, but also include landfill operations and the receipt and disposal of waste that is converted to fuel for use in our cement plants. Revenue from the receipt of waste fuels is recognized when the waste is accepted and a corresponding liability is recognized for the costs to process the waste into fuel for the manufacturing of cement or to ship the waste offsite for disposal in accordance with applicable regulations. Collectability of service contracts is due reasonably after certain milestones in the contract are performed. Milestones vary by project, but are typically calculated using monthly progress based on the percentage of completion or a customer’s engineer review of progress. The majority of the time, collection occurs within 90 days of billing and cash is received within the same fiscal year as services performed. On most projects, the customer will withhold a portion of the invoice for retainage, which may last longer than a year depending on the job. Revenue derived from paving and related services is recognized using the percentage of completion method, which approximates progress towards completion. Under the percentage of completion method, we recognize paving and related services revenue as services are rendered. 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, and therefore revenue, are opened and completed within one year, with the most activity during the spring, summer and fall. We estimate profit as the difference between total estimated revenue and total estimated cost of a contract and recognize that profit over the life of the contract based on input measures. 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. We include revisions of estimated profits on contracts in earnings under the cumulative catch-up method, under which the effect of revisions in estimates is recognized immediately. If a revised estimate of contract profitability reveals an anticipated loss on the contract, we recognize the loss in the period it is identified. 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. Contract estimates involve various assumptions and projections relative to the outcome of future events over multiple periods, including future labor productivity and availability, the nature and complexity of the work to be performed, the cost and availability of materials, the effect of delayed performance, and the availability and timing of funding from the customer. These estimates are based on our best judgment. A significant change in one or more of these estimates could affect the profitability of one or more of our contracts. We review our contract estimates regularly to assess revisions in contract values and estimated costs at completion. Inherent uncertainties in estimating costs make it at least reasonably possible that the estimates used will change within the near term and over the life of the contracts. No material adjustments to a contract were recognized in the year ended December 28, 2019 . We recognize claims when the amount of the claim can be estimated reliably and its realization is probable. In evaluating these criteria, we consider the contractual basis for the claim, the cause of any additional costs incurred, the reasonableness of those costs and the objective evidence available to support the claim. When the contract includes variable consideration, we estimate the amount of consideration to which we will be entitled in exchange for transferring the promised goods or services to a customer. The amount of estimated variable consideration included in the transaction price is the amount for which it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. Types of variable consideration include, but are not limited to, liquidated damages and other performance penalties and production and placement bonuses. The majority of contract modifications relate to the original contract and are often an extension of the original performance obligation. Predominately, modifications are not distinct from the terms in the original contract; therefore, they are considered part of a single performance obligation. We account for the modification using a cumulative catch-up adjustment. However, there are instances where goods or services in a modification are distinct from those transferred prior to the modification. In these situations, we account for the modifications as either a separate contract or prospectively depending on the facts and circumstances of the modification. Generally, construction contracts contain mobilization costs which are categorized as costs to fulfill a contract. These costs are excluded from any measure of progress toward contract fulfillment. These costs do not result in the transfer of control of a good or service to the customer and are amortized over the life of the contract. Costs and estimated earnings in excess of billings are composed principally of revenue recognized on contracts on the percentage of completion method for which billings had not been presented to customers because the amounts were not billable under the contract terms at the balance sheet date. In accordance with the contract terms, the unbilled receivables at the balance sheet date are expected to be billed in following periods. Billings in excess of costs and estimated earnings represent billings in excess of revenue recognized. Contract assets and liabilities are netted on a contract-by-contract basis. Inventories —Inventories consist of stone that has been removed from quarries and processed for future sale, cement, raw materials and finished concrete blocks. Inventories are valued at the lower of cost or market and are accounted for on a first-in first-out basis or an average cost basis. If items become obsolete or otherwise unusable or if quantities exceed what is projected to be sold within a reasonable period of time, they will be charged to costs of production in the period that the items are designated as obsolete or excess inventory. Stripping costs are costs of removing overburden and waste material to access aggregate materials and are expensed as incurred. Property, Plant and Equipment, net —Property, plant and equipment are recorded at cost, less accumulated depreciation, depletion and amortization. Expenditures for additions and improvements that significantly add to the productive capacity or extend the useful life of an asset are capitalized. Repair and maintenance costs that do not substantially expand productive capacity or extend the life of property, plant and equipment are expensed as incurred. Landfill airspace is included in property, plant and equipment at cost and is amortized based on the portion of the airspace used during the period compared to the gross estimated value of available airspace, which is updated periodically as circumstances dictate. Management reassesses the landfill airspace capacity with any changes in value recorded in cost of revenue. Capitalized landfill costs include expenditures for the acquisition of land and related airspace, engineering and permitting costs, cell construction costs and direct site improvement costs. Upon disposal of an asset, the cost and related accumulated depreciation are removed from the Company’s accounts and any gain or loss is included in general and administrative expenses. The Company reviews the carrying value of property, plant and equipment for impairment whenever events or circumstances indicate that the carrying value of an asset may not be recoverable from the estimated future cash flows expected to result from its use and eventual disposition. Such indicators may include, among others, deterioration in general economic conditions, adverse changes in the markets in which an entity operates, increases in input costs that have a negative effect on earnings and cash flows or a trend of negative or declining cash flows over multiple periods. Property, plant and equipment is tested for impairment at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets. As a result, the property, plant and equipment impairment test is at a significantly lower level than the level at which goodwill is tested for impairment. In markets where the Company does not produce downstream products, such as ready-mix concrete, asphalt paving mix and paving and related services, the lowest level of largely independent identifiable cash flows is at the individual aggregates operation or a group of aggregates operations collectively serving a local market or the cement operations. Conversely, in vertically-integrated markets, the cash flows of the downstream and upstream businesses are not largely independently identifiable and the vertically-integrated operations are considered the lowest level of largely independent identifiable cash flows. Accrued Mining and Landfill Reclamation —The mining reclamation reserve and financial commitments for landfill closure and post-closure activities are based on management’s estimate of future cost requirements to reclaim property at both currently operating and closed sites. Estimates of these obligations have been developed based on management’s interpretation of current requirements and proposed regulatory changes and are intended to approximate fair value. Costs are estimated in current dollars, inflated until the expected time of payment, and then discounted back to present value using a credit-adjusted, risk-free rate on obligations of similar maturity, adjusted to reflect the Company’s credit rating. Changes in the credit-adjusted, risk-free rate do not change recorded liabilities. However, subsequent increases in the recognized obligations are measured using a current credit-adjusted, risk-free rate. Decreases in the recognized obligations are measured at the initial credit-adjusted, risk-free rate. Significant changes in inflation rates or the amount or timing of future cost estimates typically result in both (1) a current adjustment to the recorded liability (and corresponding adjustment to the asset) and (2) a change in accretion of the liability and depreciation of the asset to be recorded prospectively over the remaining capacity of the unmined quarry or landfill. Goodwill —Goodwill represents the purchase price paid in excess of the fair value of net tangible and intangible assets acquired. Goodwill recorded in connection with the Company’s acquisitions is primarily attributable to the expected profitability, assembled workforces of the acquired businesses and the synergies expected to arise after the Company’s acquisition of those businesses. Goodwill is not amortized, but is tested annually for impairment as of the first day of the fourth quarter and at any time that events or circumstances indicate that goodwill may be impaired. A qualitative approach may first be applied to determine whether it is more likely than not that the estimated fair value of a reporting unit is less than its carrying amount. If, as a result of the qualitative assessment, it is determined that an impairment is more likely than not, the two-step quantitative impairment test is then performed, otherwise further analysis is not required. The two-step impairment test first identifies potential goodwill impairment for each reporting unit and then, if necessary, measures the amount of the impairment loss. Income Taxes —Summit Inc. is a corporation subject to income taxes in the United States. Certain subsidiaries, including Summit Holdings, or subsidiary groups of the Company are taxable separate from Summit Inc. The provision for income taxes, or Summit Inc.’s proportional share of the provision, are included in the Company’s consolidated financial statements. The Company’s deferred income tax assets and liabilities are computed for differences between the tax basis and financial statement amounts that will result in taxable or deductible amounts in the future. The computed deferred balances are based on enacted tax laws and applicable rates for the periods in which the differences are expected to affect taxable income. A valuation allowance is recognized for deferred tax assets if it is more likely than not that some portion or all of the net deferred tax assets will not be realized. In making such a determination, all available positive and negative evidence is considered, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If the Company determines it would be able to realize its deferred tax assets for which a valuation allowance had been recorded then an adjustment would be made to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company evaluates the tax positions taken on income tax returns that remain open and positions expected to be taken on the current year tax returns to identify uncertain tax positions. Unrecognized tax benefits on uncertain tax positions are recorded on the basis of a two-step process in which (1) the Company determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, the largest amount of tax benefit that is more than 50 percent likely to be realized is recognized. Interest and penalties related to unrecognized tax benefits are recorded in income tax expense (benefit). 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 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. As noted above, 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. 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. 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. New Accounting Standards — In February 2016, the Financial Accounting Standards Board FASB ("FASB") issued Accounting Standards Update ("ASU") No. 2016-02, Leases (Topic 842), which requires lessees to recognize most leases on the balance sheet. Lessees are required to disclose more quantitative and qualitative information about the leases than current U.S. GAAP requires. The ASU and subsequent amendments issued in 2018 are effective for public entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. We adopted the standard effective December 30, 2018 using the modified retrospective approach. The modified retrospective approach provides a method for recording existing leases at adoption. In addition, we elected the package of practical expedients permitted under the transition guidance within the new standard, which among other things, allowed us to carry forward the historical lease classification. In addition, we elected the hindsight practical expedient to determine the lease term for existing leases. The most significant impact upon adoption was the recognition of $36.8 million of operating lease right-of-use assets and $36.8 million operating lease liabilities. The standard had no material impact on our statements of operations and cash flows. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities, allowing more financial and nonfinancial hedging strategies to be eligible for hedge accounting. The ASU is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. The adoption of this new ASU did not have a material impact on our consolidated financial results. In June 2018, the FASB issued ASU No. 2018-07, Compensation—Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting, increasing the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. The ASU is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. The adoption of this new ASU did not have a material impact on our consolidated financial results.
Summit Materials, LLC
Company Information
Summary of Organization and Significant Accounting Policies	Summary of Organization and Significant Accounting Policies Summit Materials, LLC (“Summit LLC” and, together with its subsidiaries, 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”) 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. Principles of Consolidation –The consolidated financial statements include the accounts of Summit LLC and its majority owned subsidiaries. All intercompany balances and transactions have been eliminated. The Company attributes consolidated member’s interest and net income separately to the controlling and noncontrolling interests. Noncontrolling interests in consolidated subsidiaries represent a 20% ownership in Ohio Valley Asphalt, LLC and, prior to the initial public offering (“IPO”) and concurrent purchase of the noncontrolling interests Continental Cement Company, L.L.C. (“Continental Cement”), a 30% redeemable ownership in Continental Cement. The Company accounts for investments in entities for which it has an ownership of 20% to 50% using the equity method of accounting. In the fourth quarter of 2017, we purchased the remaining noncontrolling interest in Ohio Valley Asphalt, LLC. The Company’s fiscal year is based on a 52-53 week year with each quarter composed of 13 weeks ending on a Saturday. The 53-week year last occurred in 2015, and will occur in 2020. Use of Estimates — Preparation of these consolidated financial statements in conformity with U.S. generally accepted accounting principles (“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, Utah, Kansas 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 2019 , 2018 or 2017 . Accounts Receivable —Accounts receivable are stated at the amount management expects to collect from outstanding balances. Management provides for probable uncollectible amounts through a charge to earnings and a credit to a valuation allowance based on its assessment of the collectability of individual accounts. In establishing the allowance, management considers historical losses adjusted to take into account current market conditions and its customers’ financial condition, the amount of receivables in dispute, the current receivables aging and current payment terms. Balances that remain outstanding after reasonable collection efforts are exercised are written off through a charge to the valuation allowance. The balances billed but not paid by customers, pursuant to retainage provisions included in contracts, are generally due upon completion of the contracts. 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 plastics components, and from the provision of services, which are primarily paving and related services, but also include landfill operations, the receipt and disposal of waste that is converted to fuel for use in our cement plants. Products We earn revenue from the sale of products, which primarily include aggregates, cement, ready-mix concrete and asphalt, but also include concrete products, net of discounts or allowances, if any, and freight and delivery charges billed to customers. Freight and delivery charges associated with cement sales are recorded on a net basis together with freight costs within cost of sales. Revenue for product sales is recognized when evidence of an arrangement exists and when control passes, which generally is when the product is shipped. Aggregates and cement products are sold point-of-sale through purchase orders. When the product is sold on account, collectability typically occurs 30 to 60 days after the sale. Revenue is recognized when cash is received from the customer at the point of sale or when the products are delivered or collected on site. There are no other timing implications that will create a contract asset or liability, and contract modifications are unlikely given the timing and nature of the transaction. Material sales are likely to have multiple performance obligations if the product is sold with delivery. In these instances, delivery most often occurs on the same day as the control of the product transfers to the customer. As a result, even in the case of multiple performance obligations, the performance obligations are satisfied concurrently and revenue is recognized simultaneously. Services We earn revenue from the provision of services, which are primarily paving and related services, but also include landfill operations and the receipt and disposal of waste that is converted to fuel for use in our cement plants. Revenue from the receipt of waste fuels is recognized when the waste is accepted and a corresponding liability is recognized for the costs to process the waste into fuel for the manufacturing of cement or to ship the waste offsite for disposal in accordance with applicable regulations. Collectability of service contracts is due reasonably after certain milestones in the contract are performed. Milestones vary by project, but are typically calculated using monthly progress based on the percentage of completion or a customer’s engineer review of progress. The majority of the time, collection occurs within 90 days of billing and cash is received within the same fiscal year as services performed. On most projects, the customer will withhold a portion of the invoice for retainage, which may last longer than a year depending on the job. Revenue derived from paving and related services is recognized using the percentage of completion method, which approximates progress towards completion. Under the percentage of completion method, we recognize paving and related services revenue as services are rendered. 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, and therefore revenue, are opened and completed within one year, with the most activity during the spring, summer and fall. We estimate profit as the difference between total estimated revenue and total estimated cost of a contract and recognize that profit over the life of the contract based on input measures. 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. We include revisions of estimated profits on contracts in earnings under the cumulative catch-up method, under which the effect of revisions in estimates is recognized immediately. If a revised estimate of contract profitability reveals an anticipated loss on the contract, we recognize the loss in the period it is identified. 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. Contract estimates involve various assumptions and projections relative to the outcome of future events over multiple periods, including future labor productivity and availability, the nature and complexity of the work to be performed, the cost and availability of materials, the effect of delayed performance, and the availability and timing of funding from the customer. These estimates are based on our best judgment. A significant change in one or more of these estimates could affect the profitability of one or more of our contracts. We review our contract estimates regularly to assess revisions in contract values and estimated costs at completion. Inherent uncertainties in estimating costs make it at least reasonably possible that the estimates used will change within the near term and over the life of the contracts. No material adjustments to a contract were recognized in the year ended December 28, 2019 . We recognize claims when the amount of the claim can be estimated reliably and its realization is probable. In evaluating these criteria, we consider the contractual basis for the claim, the cause of any additional costs incurred, the reasonableness of those costs and the objective evidence available to support the claim. When the contract includes variable consideration, we estimate the amount of consideration to which we will be entitled in exchange for transferring the promised goods or services to a customer. The amount of estimated variable consideration included in the transaction price is the amount for which it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. Types of variable consideration include, but are not limited to, liquidated damages and other performance penalties and production and placement bonuses. The majority of contract modifications relate to the original contract and are often an extension of the original performance obligation. Predominately, modifications are not distinct from the terms in the original contract; therefore, they are considered part of a single performance obligation. We account for the modification using a cumulative catch-up adjustment. However, there are instances where goods or services in a modification are distinct from those transferred prior to the modification. In these situations, we account for the modifications as either a separate contract or prospectively depending on the facts and circumstances of the modification. Generally, construction contracts contain mobilization costs which are categorized as costs to fulfill a contract. These costs are excluded from any measure of progress toward contract fulfillment. These costs do not result in the transfer of control of a good or service to the customer and are amortized over the life of the contract. Costs and estimated earnings in excess of billings are composed principally of revenue recognized on contracts on the percentage of completion method for which billings had not been presented to customers because the amounts were not billable under the contract terms at the balance sheet date. In accordance with the contract terms, the unbilled receivables at the balance sheet date are expected to be billed in following periods. Billings in excess of costs and estimated earnings represent billings in excess of revenue recognized. Contract assets and liabilities are netted on a contract-by-contract basis. Inventories —Inventories consist of stone that has been removed from quarries and processed for future sale, cement, raw materials and finished concrete blocks. Inventories are valued at the lower of cost or market and are accounted for on a first-in first-out basis or an average cost basis. If items become obsolete or otherwise unusable or if quantities exceed what is projected to be sold within a reasonable period of time, they will be charged to costs of production in the period that the items are designated as obsolete or excess inventory. Stripping costs are costs of removing overburden and waste material to access aggregate materials and are expensed as incurred. Property, Plant and Equipment, net —Property, plant and equipment are recorded at cost, less accumulated depreciation, depletion and amortization. Expenditures for additions and improvements that significantly add to the productive capacity or extend the useful life of an asset are capitalized. Repair and maintenance costs that do not substantially expand productive capacity or extend the life of property, plant and equipment are expensed as incurred. Landfill airspace is included in property, plant and equipment at cost and is amortized based on the portion of the airspace used during the period compared to the gross estimated value of available airspace, which is updated periodically as circumstances dictate. Management reassesses the landfill airspace capacity with any changes in value recorded in cost of revenue. Capitalized landfill costs include expenditures for the acquisition of land and related airspace, engineering and permitting costs, cell construction costs and direct site improvement costs. Upon disposal of an asset, the cost and related accumulated depreciation are removed from the Company’s accounts and any gain or loss is included in general and administrative expenses. The Company reviews the carrying value of property, plant and equipment for impairment whenever events or circumstances indicate that the carrying value of an asset may not be recoverable from the estimated future cash flows expected to result from its use and eventual disposition. Such indicators may include, among others, deterioration in general economic conditions, adverse changes in the markets in which an entity operates, increases in input costs that have a negative effect on earnings and cash flows or a trend of negative or declining cash flows over multiple periods. Property, plant and equipment is tested for impairment at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets. As a result, the property, plant and equipment impairment test is at a significantly lower level than the level at which goodwill is tested for impairment. In markets where the Company does not produce downstream products, such as ready-mix concrete, asphalt paving mix and paving and related services, the lowest level of largely independent identifiable cash flows is at the individual aggregates operation or a group of aggregates operations collectively serving a local market or the cement operations. Conversely, in vertically-integrated markets, the cash flows of the downstream and upstream businesses are not largely independently identifiable and the vertically-integrated operations are considered the lowest level of largely independent identifiable cash flows. Accrued Mining and Landfill Reclamation —The mining reclamation reserve and financial commitments for landfill closure and post-closure activities are based on management’s estimate of future cost requirements to reclaim property at both currently operating and closed sites. Estimates of these obligations have been developed based on management’s interpretation of current requirements and proposed regulatory changes and are intended to approximate fair value. Costs are estimated in current dollars, inflated until the expected time of payment, and then discounted back to present value using a credit-adjusted, risk-free rate on obligations of similar maturity, adjusted to reflect the Company’s credit rating. Changes in the credit-adjusted, risk-free rate do not change recorded liabilities. However, subsequent increases in the recognized obligations are measured using a current credit-adjusted, risk-free rate. Decreases in the recognized obligations are measured at the initial credit-adjusted, risk-free rate. Significant changes in inflation rates or the amount or timing of future cost estimates typically result in both (1) a current adjustment to the recorded liability (and corresponding adjustment to the asset) and (2) a change in accretion of the liability and depreciation of the asset to be recorded prospectively over the remaining capacity of the unmined quarry or landfill. Goodwill —Goodwill represents the purchase price paid in excess of the fair value of net tangible and intangible assets acquired. Goodwill recorded in connection with the Company’s acquisitions is primarily attributable to the expected profitability, assembled workforces of the acquired businesses and the synergies expected to arise after the Company’s acquisition of those businesses. Goodwill is not amortized, but is tested annually for impairment as of the first day of the fourth quarter and at any time that events or circumstances indicate that goodwill may be impaired. A qualitative approach may first be applied to determine whether it is more likely than not that the estimated fair value of a reporting unit is less than its carrying amount. If, as a result of the qualitative assessment, it is determined that an impairment is more likely than not, the two-step quantitative impairment test is then performed, otherwise further analysis is not required. The two-step impairment test first identifies potential goodwill impairment for each reporting unit and then, if necessary, measures the amount of the impairment loss. Income Taxes —As a limited liability company, the Company’s federal and state income tax attributes are generally passed to its member. However, certain subsidiaries, or subsidiary groups, of the Company are taxable entities subject to income taxes in the United States and Canada, the provisions for which are included in the consolidated financial statements. Significant judgments and estimates are required in the determination of the consolidated income tax expense. The Company’s deferred income tax assets and liabilities are computed for differences between the tax basis and financial statement amounts that will result in taxable or deductible amounts in the future. The computed deferred balances are based on enacted tax laws and applicable rates for the periods in which the differences are expected to affect taxable income. A valuation allowance is recognized for deferred tax assets if it is more likely than not that some portion or all of the net deferred tax assets will not be realized. In making such a determination, all available positive and negative evidence is considered, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If the Company determines it would be able to realize its deferred tax assets for which a valuation allowance had been recorded then an adjustment would be made to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company evaluates the tax positions taken on income tax returns that remain open and positions expected to be taken on the current year tax returns to identify uncertain tax positions. Unrecognized tax benefits on uncertain tax positions are recorded on the basis of a two-step process in which (1) the Company determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, the largest amount of tax benefit that is more than 50 percent likely to be realized is recognized. Interest and penalties related to unrecognized tax benefits are recorded in income tax benefit. New Accounting Standards — In February 2016, the Financial Accounting Standards Board FASB ("FASB") issued Accounting Standards Update ("ASU") No. 2016-02, Leases (Topic 842), which requires lessees to recognize most leases on the balance sheet. Lessees are required to disclose more quantitative and qualitative information about the leases than current U.S. GAAP requires. The ASU and subsequent amendments issued in 2018 are effective for public entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. We adopted the standard effective December 30, 2018 using the modified retrospective approach. The modified retrospective approach provides a method for recording existing leases at adoption. In addition, we elected the package of practical expedients permitted under the transition guidance within the new standard, which among other things, allowed us to carry forward the historical lease classification. In addition, we elected the hindsight practical expedient to determine the lease term for existing leases. The most significant impact upon adoption was the recognition of $36.8 million of operating lease right-of-use assets and $36.8 million operating lease liabilities. The standard had no material impact on our statements of operations and cash flows. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities, allowing more financial and nonfinancial hedging strategies to be eligible for hedge accounting. The ASU is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. The adoption of this new ASU did not have a material impact on our consolidated financial results. In June 2018, the FASB issued ASU No. 2018-07, Compensation — Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting, increasing the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. The ASU is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. The adoption of this new ASU did not have a material impact on our consolidated financial results.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 28, 2019
Acquisitions	Acquisitions The Company has completed numerous acquisitions since its formation, which have been financed through a combination of debt and equity funding. 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. The following table summarizes the Company’s acquisitions by region and year: 2019 2018 2017 West 2 5 6 East (1) — 7 8 ______________________ (1) In addition, the Company acquired certain assets of a small ready-mix concrete operation in the second quarter of 2018. The table below summarizes aggregated information regarding the fair values of the assets acquired and liabilities assumed as of the respective acquisition dates. 2019 2018 Financial assets $ — $ 14,769 Inventories 52 18,313 Property, plant and equipment 3,542 124,957 Intangible assets — 3,175 Other assets — 1,539 Financial liabilities (36 ) (13,529 ) Other long-term liabilities — (8,125 ) Net assets acquired 3,558 141,099 Goodwill 1,834 154,120 Purchase price 5,392 295,219 Acquisition-related liabilities — (49,202 ) Net cash paid for acquisitions $ 5,392 $ 246,017 Acquisition-Related Liabilities —A number of acquisition-related liabilities have been recorded subject to terms in the relevant purchase agreements, including deferred consideration and noncompete payments. Noncompete payments have been accrued where certain former owners of newly acquired companies have entered into standard noncompete arrangements. Subject to terms and conditions stated in these noncompete agreements, payments are generally made over a five-year period. Deferred consideration is purchase price consideration paid in the future as agreed to in the purchase agreement and is not contingent on future events. Deferred consideration is generally scheduled to be paid in years ranging from 5 to 20 years in annual installments. The remaining payments due under these noncompete and deferred consideration agreements are as follows: 2020 $ 31,708 2021 9,705 2022 3,411 2023 2,657 2024 2,620 Thereafter 7,020 Total scheduled payments 57,121 Present value adjustments (7,889 ) Total noncompete obligations and deferred consideration $ 49,232 Accretion on the deferred consideration and noncompete obligations is recorded in interest expense.
Summit Materials, LLC
Acquisitions	Acquisitions The Company has completed numerous acquisitions since its formation, which have been financed through a combination of debt and equity funding. 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. The following table summarizes the Company’s acquisitions by region and year: 2019 2018 2017 West 2 5 6 East (1) — 7 8 ______________________ (1) In addition, the Company acquired certain assets of a small ready-mix concrete operation in the second quarter of 2018. The table below summarizes aggregated information regarding the fair values of the assets acquired and liabilities assumed as of the respective acquisition dates. 2019 2018 Financial assets $ — $ 14,769 Inventories 52 18,313 Property, plant and equipment 3,542 124,957 Intangible assets — 3,175 Other assets — 1,539 Financial liabilities (36 ) (13,529 ) Other long-term liabilities — (8,125 ) Net assets acquired 3,558 141,099 Goodwill 1,834 154,120 Purchase price 5,392 295,219 Acquisition-related liabilities — (49,202 ) Net cash paid for acquisitions $ 5,392 $ 246,017 Acquisition-Related Liabilities —A number of acquisition-related liabilities have been recorded subject to terms in the relevant purchase agreements, including deferred consideration and noncompete payments. Noncompete payments have been accrued where certain former owners of newly acquired companies have entered into standard noncompete arrangements. Subject to terms and conditions stated in these noncompete agreements, payments are generally made over a five-year period. Deferred consideration is purchase price consideration paid in the future as agreed to in the purchase agreement and is not contingent on future events. Deferred consideration is generally scheduled to be paid in years ranging from 5 to 20 years in annual installments. The remaining payments due under these noncompete and deferred consideration agreements are as follows: 2020 $ 29,208 2021 7,205 2022 3,411 2023 2,657 2024 2,620 Thereafter 7,020 Total scheduled payments 52,121 Present value adjustments (7,524 ) Total noncompete obligations and deferred consideration $ 44,597

Goodwill

Goodwill	12 Months Ended
	Dec. 28, 2019
Goodwill	Goodwill As of December 28, 2019 , the Company had 11 reporting units with goodwill for which the annual goodwill impairment test was completed. We perform the annual impairment test on the first day of the fourth quarter each year. In 2019, we performed a two-step quantitative analysis on all of our reporting units. Step 1 of that analysis compares the estimated the fair value of the reporting units using an income approach (i.e., a discounted cash flow technique) and a market approach to the carrying value of the reporting unit. If the estimated fair value exceeds its carrying value, the goodwill of the reporting unit is not considered impaired. If the carrying value of the reporting unit exceeds its fair value, we proceed to the second step to measure the amount of potential impairment loss. Based on this analysis, it was determined that the reporting units’ fair values were greater than their carrying values and no impairment charges were recognized in 2019 . The accumulated impairment charges recognized in periods prior to 2017 totaled $68.2 million . These estimates of a reporting unit’s fair value involve significant management estimates and assumptions, including but not limited to sales prices of similar assets, assumptions related to future profitability, cash flows, and discount rates. These estimates are based upon historical trends, management’s knowledge and experience and overall economic factors, including projections of future earnings potential. Developing discounted future cash flow estimates in applying the income approach required management to evaluate its intermediate to longer-term strategies, including, but not limited to, estimates about revenue growth, operating margins, capital requirements, inflation and working capital management. The development of appropriate rates to discount the estimated future cash flows required the selection of risk premiums, which can materially affect the present value of estimated future cash flows. Within the West segment, as a result of management changes in 2019, we integrated our Austin operations with those of our Houston operations, resulting in one reporting unit for goodwill. The following table presents goodwill by reportable segments and in total: West East Cement Total Balance—December 30, 2017 $ 526,290 $ 305,374 $ 204,656 $ 1,036,320 Acquisitions 59,148 101,431 — 160,579 Foreign currency translation adjustments (4,871 ) — — (4,871 ) Balance, December 29, 2018 $ 580,567 $ 406,805 $ 204,656 $ 1,192,028 Acquisitions (1) 1,657 3,621 — 5,278 Foreign currency translation adjustments 2,393 — — 2,393 Balance, December 28, 2019 $ 584,617 $ 410,426 $ 204,656 $ 1,199,699 ______________________ (1) Reflects goodwill from 2019 acquisitions and working capital adjustments from prior year acquisitions.
Summit Materials, LLC
Goodwill	Goodwill As of December 28, 2019 , the Company had 11 reporting units with goodwill for which the annual goodwill impairment test was completed. We perform the annual impairment test on the first day of the fourth quarter each year. In 2019, we performed a two-step quantitative analysis on all of our reporting units. Step 1 of that analysis compares the estimated the fair value of the reporting units using an income approach (i.e., a discounted cash flow technique) and a market approach to the carrying value of the reporting unit. If the estimated fair value exceeds its carrying value, the goodwill of the reporting unit is not considered impaired. If the carrying value of the reporting unit exceeds its fair value, we proceed to the second step to measure the amount of potential impairment loss. Based on this analysis, it was determined that the reporting units’ fair values were greater than their carrying values and no impairment charges were recognized in 2019 . The accumulated impairment charges recognized in periods prior to 2017 totaled $68.2 million . These estimates of a reporting unit’s fair value involve significant management estimates and assumptions, including but not limited to sales prices of similar assets, assumptions related to future profitability, cash flows, and discount rates. These estimates are based upon historical trends, management’s knowledge and experience and overall economic factors, including projections of future earnings potential. Developing discounted future cash flow estimates in applying the income approach required management to evaluate its intermediate to longer-term strategies, including, but not limited to, estimates about revenue growth, operating margins, capital requirements, inflation and working capital management. The development of appropriate rates to discount the estimated future cash flows required the selection of risk premiums, which can materially affect the present value of estimated future cash flows. Within the West segment, as a result of management changes in 2019, we integrated our Austin operations with those of our Houston operations, resulting in one reporting unit for goodwill. The following table presents goodwill by reportable segments and in total: West East Cement Total Balance—December 30, 2017 $ 527,290 $ 305,374 $ 204,656 $ 1,037,320 Acquisitions 59,148 101,431 — 160,579 Foreign currency translation adjustments (4,871 ) — — (4,871 ) Balance, December 29, 2018 $ 581,567 $ 406,805 $ 204,656 $ 1,193,028 Acquisitions (1) 1,657 3,621 — 5,278 Foreign currency translation adjustments 2,393 — — 2,393 Balance, December 28, 2019 $ 585,617 $ 410,426 $ 204,656 $ 1,200,699 ______________________ (1) Reflects goodwill from 2019 acquisitions and working capital adjustments from prior year acquisitions.

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 28, 2019
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, and is recognized using the percentage of completion method. The majority of our construction service contracts, and therefore revenue, are opened and completed within one year, with the most activity during the spring, summer and fall. Revenue by product for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 consisted of the following: 2019 2018 2017 Revenue by product*: Aggregates $ 469,670 $ 373,824 $ 313,383 Cement 266,235 258,876 282,041 Ready-mix concrete 607,622 584,114 492,302 Asphalt 330,750 301,247 285,653 Paving and related services 360,234 379,540 371,763 Other 187,629 203,401 187,433 Total revenue $ 2,222,140 $ 2,101,002 $ 1,932,575 ______________________ * Revenue from the liquid asphalt terminals is included in asphalt revenue. The following table outlines the significant changes in contract assets and contract liability balances from December 29, 2018 to December 28, 2019 . Also included in the table is the net change in the estimate as a percentage of aggregate revenue for such contracts: Costs and estimated Billings in excess earnings in of costs and excess of billings estimated earnings Balance—December 29, 2018 $ 18,602 $ 11,840 Changes in revenue billed, contract price or cost estimates (5,558 ) 1,988 Other 44 36 Balance—December 28, 2019 $ 13,088 $ 13,864 Accounts receivable, net consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Trade accounts receivable $ 191,672 $ 157,601 Construction contract receivables 47,966 47,994 Retention receivables 17,808 15,010 Receivables from related parties 1,596 629 Accounts receivable 259,042 221,234 Less: Allowance for doubtful accounts (5,786 ) (6,716 ) Accounts receivable, net $ 253,256 $ 214,518 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, and is recognized using the percentage of completion method. The majority of our construction service contracts, and therefore revenue, are opened and completed within one year, with the most activity during the spring, summer and fall. Revenue by product for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 consisted of the following: 2019 2018 2017 Revenue by product*: Aggregates $ 469,670 $ 373,824 $ 313,383 Cement 266,235 258,876 282,041 Ready-mix concrete 607,622 584,114 492,302 Asphalt 330,750 301,247 285,653 Paving and related services 360,234 379,540 371,763 Other 187,629 203,401 187,433 Total revenue $ 2,222,140 $ 2,101,002 $ 1,932,575 ______________________ *Revenue from the liquid asphalt terminals is included in asphalt revenue. The following table outlines the significant changes in contract assets and contract liability balances from December 29, 2018 to December 28, 2019 . Also included in the table is the net change in the estimate as a percentage of aggregate revenue for such contracts: Costs and estimated Billings in excess earnings in of costs and excess of billings estimated earnings Balance—December 29, 2018 $ 18,602 $ 11,840 Changes in revenue billed, contract price or cost estimates (5,558 ) 1,988 Other 44 36 Balance—December 28, 2019 $ 13,088 $ 13,864 Accounts receivable, net consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Trade accounts receivable $ 191,672 $ 157,601 Construction contract receivables 47,966 47,994 Retention receivables 17,808 15,010 Receivables from related parties 1,596 629 Accounts receivable 259,042 221,234 Less: Allowance for doubtful accounts (5,786 ) (6,716 ) Accounts receivable, net $ 253,256 $ 214,518 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	12 Months Ended
	Dec. 28, 2019
Inventory [Line Items]
Inventories	Inventories Inventories consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Aggregate stockpiles $ 140,461 $ 151,300 Finished goods 33,023 34,993 Work in process 7,664 7,478 Raw materials 23,639 20,080 Total $ 204,787 $ 213,851
Summit Materials, LLC
Inventory [Line Items]
Inventories	Inventories Inventories consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Aggregate stockpiles $ 140,461 $ 151,300 Finished goods 33,023 34,993 Work in process 7,664 7,478 Raw materials 23,639 20,080 Total $ 204,787 $ 213,851

Property, Plant and Equipment,

Property, Plant and Equipment, net and Intangibles, net	12 Months Ended
	Dec. 28, 2019
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, net and Intangibles, net	Property, Plant and Equipment, net and Intangibles, net Property, plant and equipment, net consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Land (mineral bearing) and asset retirement costs $ 333,024 $ 323,553 Land (non-mineral bearing) 182,065 184,029 Buildings and improvements 178,088 173,559 Plants, machinery and equipment 1,318,512 1,239,793 Mobile equipment and barges 501,809 468,313 Truck and auto fleet 54,838 51,938 Landfill airspace and improvements 49,766 49,754 Office equipment 43,155 39,794 Construction in progress 42,007 43,650 Property, plant and equipment 2,703,264 2,574,383 Less accumulated depreciation, depletion and amortization (955,815 ) (794,251 ) Property, plant and equipment, net $ 1,747,449 $ 1,780,132 Depreciation on property, plant and equipment, including assets subject to capital leases, is generally computed on a straight-line basis. Depletion of mineral reserves is computed based on the portion of the reserves used during the period compared to the gross estimated value of proven and probable reserves, which is updated periodically as circumstances dictate. Leasehold improvements are amortized on a straight-line basis over the lesser of the asset’s useful life or the remaining lease term. The estimated useful lives are generally as follows: Buildings and improvements 10 - 30 years Plant, machinery and equipment 15 - 20 years Office equipment 3 - 7 years Truck and auto fleet 5 - 8 years Mobile equipment and barges 6 - 8 years Landfill airspace and improvements 10 - 30 years Other 4 - 20 years Depreciation, depletion and amortization expense of property, plant and equipment was $196.8 million , $199.6 million and $174.4 million in the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 , respectively. Property, plant and equipment at December 28, 2019 and December 29, 2018 included $82.7 million and $67.7 million , respectively, of finance leases for certain equipment and a building with accumulated amortization of $24.9 million and $19.3 million , respectively. The equipment leases generally have terms of less than five years and the building lease had an original term of 30 years . Approximately $16.0 million and $15.6 million of the future obligations associated with the finance leases are included in accrued expenses as of December 28, 2019 and December 29, 2018 , respectively, and the present value of the remaining finance lease payments, $40.4 million and $33.6 million , respectively, is included in other noncurrent liabilities on the consolidated balance sheets. Future minimum rental commitments under long-term capital leases are $18.6 million , $21.9 million , $14.9 million , $1.7 million , and $2.3 million for the years ended 2020, 2021, 2022, 2023 and 2024, respectively. Assets are assessed for impairment charges when identified for disposition. The net gain from asset dispositions recognized in general and administrative expenses in fiscal years 2019 , 2018 and 2017 was $10.7 million , $12.6 million and $7.5 million , respectively. No material impairment charges have been recognized on assets held for use in fiscal 2019 , 2018 or 2017 . Intangible Assets —The Company’s intangible assets are primarily composed of lease agreements and reserve rights. The assets related to 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 to contract-royalty rates. The reserve rights relate to aggregate reserves to which the Company has the rights of ownership, but do not own the reserves. The intangible assets are amortized on a straight-line basis over the lives of the leases. The following table shows intangible assets by type and in total: December 28, 2019 December 29, 2018 Gross Net Gross Net Carrying Accumulated Carrying Carrying Accumulated Carrying Amount Amortization Amount Amount Amortization Amount Mineral leases $ 19,064 $ (6,408 ) $ 12,656 $ 19,064 $ (5,259 ) $ 13,805 Reserve rights 6,234 (2,248 ) 3,986 6,234 (1,940 ) 4,294 Trade names 1,000 (958 ) 42 1,000 (858 ) 142 Other 7,566 (752 ) 6,814 409 (190 ) 219 Total intangible assets $ 33,864 $ (10,366 ) $ 23,498 $ 26,707 $ (8,247 ) $ 18,460 Amortization expense in fiscal 2019 , 2018 and 2017 was $2.1 million , $1.5 million and $1.3 million , respectively. The estimated amortization expense for intangible assets for each of the next five years and thereafter is as follows: 2020 $ 2,526 2021 2,138 2022 2,142 2023 2,009 2024 1,914 Thereafter 12,769 Total $ 23,498
Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, net and Intangibles, net	Property, Plant and Equipment, net and Intangibles, net Property, plant and equipment, net consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Land (mineral bearing) and asset retirement costs $ 333,024 $ 323,553 Land (non-mineral bearing) 182,065 184,029 Buildings and improvements 178,088 173,559 Plants, machinery and equipment 1,318,512 1,239,793 Mobile equipment and barges 501,809 468,313 Truck and auto fleet 54,838 51,938 Landfill airspace and improvements 49,766 49,754 Office equipment 43,155 39,794 Construction in progress 42,007 43,650 Property, plant and equipment 2,703,264 2,574,383 Less accumulated depreciation, depletion and amortization (955,815 ) (794,251 ) Property, plant and equipment, net $ 1,747,449 $ 1,780,132 Depreciation on property, plant and equipment, including assets subject to capital leases, is generally computed on a straight-line basis. Depletion of mineral reserves is computed based on the portion of the reserves used during the period compared to the gross estimated value of proven and probable reserves, which is updated periodically as circumstances dictate. Leasehold improvements are amortized on a straight-line basis over the lesser of the asset’s useful life or the remaining lease term. The estimated useful lives are generally as follows: Buildings and improvements 10-30 years Plant, machinery and equipment 15 - 20 years Office equipment 3-7 years Truck and auto fleet 5-8 years Mobile equipment and barges 6-8 years Landfill airspace and improvements 10-30 years Other 4-20 years Depreciation, depletion and amortization expense of property, plant and equipment was $196.8 million , $199.6 million and $174.4 million in the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 , respectively. Property, plant and equipment at December 28, 2019 and December 29, 2018 included $82.7 million and $67.7 million , respectively, of finance leases for certain equipment and a building with accumulated amortization of $24.9 million and $19.3 million , respectively. The equipment leases generally have terms of less than five years and the building lease had an original term of 30 years . Approximately $16.0 million and $15.6 million of the future obligations associated with the finance leases are included in accrued expenses as of December 28, 2019 and December 29, 2018 , respectively, and the present value of the remaining finance lease payments, $40.4 million and $33.6 million , respectively, is included in other noncurrent liabilities on the consolidated balance sheets. Future minimum rental commitments under long-term capital leases are $18.6 million , $21.9 million , $14.9 million , $1.7 million , and $2.3 million for the years ended 2020, 2021, 2022, 2023 and 2024, respectively. Assets are assessed for impairment charges when identified for disposition. The net gain from asset dispositions recognized in general and administrative expenses in fiscal years 2019 , 2018 and 2017 was $10.7 million , $12.6 million and $7.5 million , respectively. No material impairment charges have been recognized on assets held for use in fiscal 2019 , 2018 or 2017 . Intangible Assets —The Company’s intangible assets are primarily composed of lease agreements and reserve rights. The assets related to 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 to contract-royalty rates. The reserve rights relate to aggregate reserves to which the Company has the rights of ownership, but do not own the reserves. The intangible assets are amortized on a straight-line basis over the lives of the leases. The following table shows intangible assets by type and in total: December 28, 2019 December 29, 2018 Gross Net Gross Net Carrying Accumulated Carrying Carrying Accumulated Carrying Amount Amortization Amount Amount Amortization Amount Mineral leases $ 19,064 $ (6,408 ) $ 12,656 $ 19,064 $ (5,259 ) $ 13,805 Reserve rights 6,234 (2,248 ) 3,986 6,234 (1,940 ) 4,294 Trade names 1,000 (958 ) 42 1,000 (858 ) 142 Other 7,566 (752 ) 6,814 409 (190 ) 219 Total intangible assets $ 33,864 $ (10,366 ) $ 23,498 $ 26,707 $ (8,247 ) $ 18,460 Amortization expense in fiscal 2019 , 2018 and 2017 was $2.1 million , $1.5 million and $1.3 million , respectively. The estimated amortization expense for intangible assets for each of the next five years and thereafter is as follows: 2020 $ 2,526 2021 2,138 2022 2,142 2023 2,009 2024 1,914 Thereafter 12,769 Total $ 23,498

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 28, 2019
Schedule Of Accrued Expenses [Line Items]
Accrued Expenses	Accrued Expenses Accrued expenses consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Interest $ 26,892 $ 26,223 Payroll and benefits 29,356 15,952 Finance lease obligations 16,007 15,557 Insurance 14,968 13,625 Non-income taxes 7,666 7,442 Professional fees 902 1,408 Other (1) 24,214 20,284 Total $ 120,005 $ 100,491 ______________________ (1) Consists primarily of subcontractor and working capital settlement accruals and deferred revenue.
Summit Materials, LLC
Schedule Of Accrued Expenses [Line Items]
Accrued Expenses	Accrued Expenses Accrued expenses consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Interest $ 26,892 $ 26,223 Payroll and benefits 29,356 15,952 Finance lease obligations 16,007 15,557 Insurance 14,968 13,625 Non-income taxes 7,898 7,674 Professional fees 902 1,408 Other (1) 24,214 19,590 Total $ 120,237 $ 100,029 ______________________ (1) Consists primarily of subcontractor and working capital settlement accruals and deferred revenue.

Debt

Debt	12 Months Ended
	Dec. 28, 2019
Debt	Debt Debt consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Term Loan, due 2024: $624.3 million and $630.6 million, net of $1.1 million and $1.3 million discount at December 28, 2019 and December 29, 2018, respectively $ 623,140 $ 629,268 8 1/2% Senior Notes, due 2022 — 250,000 6 1/8% Senior Notes, due 2023: $650.0 million, net of $0.9 million and $1.1 million discount at December 28, 2019 and December 29, 2018, respectively 649,133 648,891 5 1/8% Senior Notes, due 2025 300,000 300,000 6 1⁄2% Senior Notes, due 2027 300,000 — Total 1,872,273 1,828,159 Current portion of long-term debt 7,942 6,354 Long-term debt $ 1,864,331 $ 1,821,805 The contractual payments of long-term debt, including current maturities, for the five years subsequent to December 28, 2019 , are as follows: 2020 $ 7,942 2021 6,354 2022 6,354 2023 656,354 2024 597,251 Thereafter 600,000 Total 1,874,255 Less: Original issue net discount (1,982 ) Less: Capitalized loan costs (13,274 ) Total debt $ 1,858,999 Senior Notes —On March 15, 2019, Summit LLC and Summit Finance (together, 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 “2019 Indenture”). The 2019 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 2019 Indenture also contains customary events of default. 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 2019 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 million of 6.125% senior notes due July 2023 (the “2023 Notes” and collectively with the 2022 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 2019 Indenture. Interest on the 2023 Notes is payable semi-annually in arrears on January 15 and July 15 of each year. In April, August and November 2015, $288.2 million , $183.0 million and $153.8 million , respectively, in aggregate principal amount of the then outstanding 10 1/2% senior notes due January 31, 2020 (the “2020 Notes”) were redeemed at a price equal to par plus an applicable premium and the indenture under which the 2020 Notes were issued was satisfied and discharged. As a result of the redemptions, net charges of $56.5 million were recognized for the year ended December 31, 2016. The fees included $66.6 million for the applicable prepayment premium and $11.9 million for the write-off of deferred financing fees, partially offset by $22.0 million of net benefit from the write-off of the original issuance net premium. As of December 28, 2019 and December 29, 2018 , 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. During 2018 and 2017, Summit LLC entered into three different amendments to the Credit Agreement, which among other things, reduced the applicable margin in respect to the outstanding principal amount at the time of the respective amendments. 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 December 28, 2019 or December 29, 2018 . As of December 28, 2019 , we had remaining borrowing capacity of $329.8 million under the revolving credit facility, which is net of $15.2 million of outstanding letters of credit. The outstanding letters of credit are renewed annually and support required bonding on construction projects 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 December 28, 2019 and December 29, 2018 , Summit LLC was in compliance with all financial covenants under the Credit Agreement. 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 years ended December 28, 2019 and December 29, 2018 : Deferred financing fees Balance—December 30, 2017 $ 19,033 Loan origination fees 550 Amortization (4,108 ) Balance—December 29, 2018 $ 15,475 Loan origination fees 6,312 Amortization (3,501 ) Write off of deferred financing fees (2,850 ) Balance—December 28, 2019 $ 15,436 Other —On January 15, 2015, the Company’s wholly-owned subsidiary in British Columbia, Canada entered into an agreement with HSBC 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) $0.4 million CAD revolving credit commitment to provide guarantees on behalf of that subsidiary. There were no amounts outstanding under this agreement as of December 28, 2019 or December 29, 2018 .
Summit Materials, LLC
Debt	Debt Debt consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Term Loan, due 2024: $624.3 million and $630.6 million, net of $1.1 million and $1.3 million discount at December 28, 2019 and December 29, 2018, respectively $ 623,140 $ 629,268 8 1/2% Senior Notes, due 2022 — 250,000 6 1/8% Senior Notes, due 2023: $650.0 million, net of $0.9 million and $1.1 million discount at December 28, 2019 and December 29, 2018, respectively 649,133 648,891 5 1/8% Senior Notes, due 2025 300,000 300,000 61⁄2% Senior Notes, due 2027 300,000 — Total 1,872,273 1,828,159 Current portion of long-term debt 7,942 6,354 Long-term debt $ 1,864,331 $ 1,821,805 The contractual payments of long-term debt, including current maturities, for the five years subsequent to December 28, 2019 , are as follows: 2020 $ 7,942 2021 6,354 2022 6,354 2023 656,354 2024 597,251 Thereafter 600,000 Total 1,874,255 Less: Original issue net discount (1,982 ) Less: Capitalized loan costs (13,274 ) Total debt $ 1,858,999 Senior Notes — On March 15, 2019, Summit LLC and Summit Materials Finance Corp., an indirect wholly-owned subsidiary of Summit LLC ("Finance Corp." and with Summit LLC, 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 “2019 Indenture”). The 2019 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 2019 Indenture also contains customary events of default. 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 2019 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 2022 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 2019 Indenture. Interest on the 2023 Notes is payable semi-annually in arrears on January 15 and July 15 of each year. In April, August and November 2015, $288.2 million , $183.0 million and $153.8 million , respectively, in aggregate principal amount of the then outstanding 10 1 / 2 % senior notes due January 31, 2020 (the “2020 Notes”) were redeemed at a price equal to par plus an applicable premium and the indenture under which the 2020 Notes were issued was satisfied and discharged. As a result of the redemptions, net charges of $56.5 million were recognized for the year ended December 31, 2016. The fees included $66.6 million for the applicable prepayment premium and $11.9 million for the write-off of deferred financing fees, partially offset by $22.0 million of net benefit from the write-off of the original issuance net premium. As of December 28, 2019 and December 29, 2018 , 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. During 2018 and 2017, Summit LLC entered into three different amendments to the Credit Agreement, which among other things, reduced the applicable margin in respect to the outstanding principal amount at the time of the respective amendments. 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 December 28, 2019 or December 29, 2018 . As of December 28, 2019 , we had remaining borrowing capacity of $329.8 million under the revolving credit facility, which is net of $15.2 million of outstanding letters of credit. The outstanding letters of credit are renewed annually and support required bonding on construction projects 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 December 28, 2019 and December 29, 2018 , Summit LLC was in compliance with all financial covenants under the Credit Agreement. 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 years ended December 28, 2019 and December 29, 2018 : Deferred financing fees Balance—December 30, 2017 $ 19,033 Loan origination fees 550 Amortization (4,108 ) Balance—December 29, 2018 $ 15,475 Loan origination fees 6,312 Amortization (3,501 ) Write off of deferred financing fees (2,850 ) Balance—December 28, 2019 $ 15,436 Other —On January 15, 2015, the Company’s wholly-owned subsidiary in British Columbia, Canada entered into an agreement with HSBC 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) $0.4 million CAD revolving credit commitment to provide guarantees on behalf of that subsidiary. There were no amounts outstanding under this agreement as of December 28, 2019 or December 29, 2018 .

Income Taxes

Income Taxes	12 Months Ended
	Dec. 28, 2019
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 consolidated financial statements. For the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 , income taxes consisted of the following: 2019 2018 2017 Provision for income taxes: Current $ 69 $ 463 $ 2,530 Deferred 17,032 59,284 (286,507 ) Income tax expense (benefit) $ 17,101 $ 59,747 $ (283,977 ) The effective tax rate on pre-tax income differs from the U.S. statutory rate of 21% , 21% , and 35% for 2019 , 2018 and 2017 , respectively, due to the following: 2019 2018 2017 Income tax expense (benefit) at federal statutory tax rate $ 16,427 $ 20,177 $ (55,365 ) Less: Income tax benefit at federal statutory tax rate for LLC entities (658 ) (561 ) (2,123 ) State and local income taxes 3,792 4,894 (5,209 ) Permanent differences (6,272 ) (5,537 ) (4,410 ) Effective tax rate change (2,006 ) 4,034 216,904 Unrecognized tax benefits 18,885 22,663 — Tax receivable agreement (benefit) expense 2,436 (8,282 ) 104,804 Change in valuation allowance (17,691 ) 17,592 (500,162 ) Impact of LP Unit ownership change — — (31,790 ) Other 2,188 4,767 (6,626 ) Income tax expense (benefit) $ 17,101 $ 59,747 $ (283,977 ) The following table summarizes the components of the net deferred income tax asset (liability) as December 28, 2019 and December 29, 2018 : 2019 2018 Deferred tax assets (liabilities): Net intangible assets $ 240,790 $ 275,412 Accelerated depreciation (201,126 ) (185,020 ) Net operating loss 164,335 143,234 Investment in limited partnership (31,987 ) (29,981 ) Mining reclamation reserve 2,018 1,600 Working capital (e.g., accrued compensation, prepaid assets) 37,287 36,932 Interest expense limitation carryforward 2,691 2,586 Less valuation allowance (1,675 ) (19,366 ) Deferred tax assets 212,333 225,397 Less foreign deferred tax liability (included in other noncurrent liabilities) (8,267 ) (5,133 ) Net deferred tax asset $ 204,066 $ 220,264 As of December 28, 2019 , $384.7 million of our deferred tax assets subject to our TRA are included in the net intangible assets and the net operating loss line items above. Our income tax expense (benefit) was $17.1 million , $59.7 million and $(284.0) million in the fiscal years ended 2019 , 2018 and 2017 , respectively. Our effective income tax rate in 2019 and 2018 was impacted by the IRS interpretative guidance of TCJA, a change in state tax rates and a reduction in the amount of our TRA liability. We recorded an income tax benefit in fiscal 2017, primarily related to the release of the valuation allowance as discussed below, partially offset by charge related to the decrease in the federal statutory corporate tax rate. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible, as well as consideration of tax-planning strategies we may seek to utilize net operating loss carryforwards that begin to expire in 2030. Prior to 2017, we concluded that it was not more likely than not that we would fully realize those deferred tax assets, and therefore recorded a partial valuation allowance against those deferred tax assets as of December 31, 2016. However, the amount of cumulative income increased significantly during the year ended December 30, 2017. As a result of this significant positive evidence, in the third quarter of 2017, we determined that the deferred tax assets had become more likely than not of becoming realizable and therefore released the majority of the valuation allowance. The Company updates the analysis, and adjusted the valuation allowance for interest expense carryforwards limited under TCJA based on updated forecast models each year. On December 22, 2017, the Tax Cuts and Jobs Act of 2017 (“TCJA”) was enacted. Among other things, the TCJA, beginning January 1, 2018, reduced the federal statutory rate from 35% to 21% and extended bonus depreciation provisions. In addition, the TCJA prescribes the application of net operating loss carryforwards generated in 2018 and beyond will be limited, 100% asset expensing will be allowed through 2022 and begin to phase out in 2023, and the amount of interest expense we are able deduct may also be limited in future years. As a result of the enactment of TCJA and other state effective rate changes, we reduced the carrying value of our net deferred tax assets in the fourth quarter of 2017 by $216.9 million to reflect the revised federal statutory rate and other state statutory rates which will be in effect at the time those deferred tax assets are expected to be realized. The TCJA contains many provisions which continue to be clarified through new regulations. As permitted by Staff Accounting Bulletin 118 issued by the SEC on December 22, 2017, we completed our accounting of the impacts of the TCJA. We completed our analysis within 2018 consistent with the guidance of SAB 118 and any adjustments during the measurement period have been included in net earnings from continuing operations as an adjustment to income tax expense. As such, in the fourth quarter of 2018, we recorded additional tax expense of $17.6 million resulting from the IRS interpretative guidance of TCJA. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: Unrealized Tax Benefits Balance—December 30, 2017 $ — Additions based on tax position in 2018 22,663 Balance—December 29, 2018 $ 22,663 Additions based on tax position in 2019 18,885 Balance—December 28, 2019 $ 41,548 At December 28, 2019 and December 29, 2018, there was $41.5 million and $22.7 million , respectively, of unrecognized tax benefits that if recognized would affect the annual effective tax rate. We did not recognize interest or penalties related to this amount as it is offset by other attributes. There were no uncertain tax positions for the year ended December 30, 2017. Our net operating loss carryforward deferred tax assets begin to expire in 2030 and are expected to reverse before expiration. Therefore, we have not given consideration to any potential tax planning strategies as a source of future taxable income to monetize those net operating loss carryforwards. The Company will continue to monitor facts and circumstances, including our analysis of other sources of taxable income, in the reassessment of the likelihood that the tax benefit of our deferred tax assets will be realized. As of December 28, 2019 , Summit Inc. had federal net operating loss carryforwards of $822 million , which expire between 2030 and 2038. As of December 29, 2018, $411 million of our federal net operating losses were under the terms of our TRA. In addition, Summit Inc. has alternative minimum tax credits of $0.2 million as of December 28, 2019 , which do not expire. As of December 28, 2019 and December 29, 2018 , Summit Inc. had a valuation allowance on net deferred tax assets of $1.7 million and $19.4 million , respectively, where realization of our interest tax attributes and net operating losses are not more likely than not. 2019 2018 Valuation Allowance: Beginning balance $ (19,366 ) $ (1,675 ) Additional basis from exchanged LP Units — (99 ) Current year decreases (increases) from operations 17,691 (17,592 ) Ending balance $ (1,675 ) $ (19,366 ) Tax Receivable Agreement — During 2015, the Company entered into a TRA with the holders of LP Units and certain other pre-initial public offering owners (“Investor Entities”) 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. When LP Units are exchanged for an equal number of newly-issued shares of Summit Inc.’s Class A common stock, these exchanges result in new deferred tax assets. Using tax rates in effect as of each year end, $1.1 million and $2.0 million of deferred tax assets were created during the years ended December 28, 2019 and December 29, 2018 , respectively, when LP Units were exchanged for shares of Class A common stock. Each year, we update our estimate as to when TRA payments will be made. As noted above, when payments are made under the TRA, a portion of the payment made will be characterized as imputed interest under IRS regulations. The TCJA enacted in late 2017 contained provisions whereby interest expense deductions may be limited, and the IRS issued proposed regulations in late 2018 around the deductibility of interest expense. Under our forecast prepared at the end of 2018, we expected the amount of imputed interest based on future TRA payments would result in interest expense deductions being limited, and therefore we would not benefit from that deduction. However, based on the updated forecast model at the end of 2019, which updated our forecast of the timing of TRA payments, we believe that our interest expense deductions will not be limited under the proposed regulations. We also updated our estimate of the state income tax rate that will be in effect at the date the TRA payments are made. As a result of our updated state income tax rate, and the imputed interest limitation noted above, we have increased our TRA liability by $16.2 million and reduced it by $22.7 million as of December 28, 2019 and December 29, 2018, respectively. In the third quarter of 2017, as a result of the analysis of the realizability of our deferred tax assets as indicated above, we reduced the valuation allowance against our deferred tax assets, including those deferred tax assets subject to the TRA. Further, we determined the TRA liability to be probable of being payable and, as such, we recorded 85% of the deferred tax assets subject to the TRA, or $501.8 million , as TRA liability. Our TRA liability as of December 28, 2019 and December 29, 2018 was $327.0 million and $309.7 million , respectively, of which $0.0 million and $0.7 million was classified as accrued expenses, 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 applicable to a corporate resident in New York, New York. For the years ended December 28, 2019 and December 29, 2018 , Summit Holdings paid tax distributions totaling $0.1 million and $0.1 million , respectively, to holders of its LP Units, other than Summit Inc. C Corporation Subsidiaries — The effective income tax rate for the C corporations differ from the statutory federal rate primarily due to (1) tax depletion expense (benefit) in excess of the expense recorded under U.S. GAAP, (2) state income taxes and the effect of graduated tax rates, (3) various other items such as limitations on meals and entertainment and other costs and (4) unrecognized tax benefits. The effective income tax rate for the Canadian subsidiary is not significantly different from its historical effective tax rate. No material interest or penalties were recognized in income tax expense during the years ended December 28, 2019 , December 29, 2018 or December 30, 2017 . Tax years from 2014 to 2018 remain open and subject to audit by federal, Canadian, and state tax authorities.
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 member and is generally not subject to federal or state income tax. However, certain subsidiaries, or subsidiary groups, file federal, state, and Canadian income tax returns due to their status as C corporations or laws within that jurisdiction. The provision for income taxes is primarily composed of federal, state and local income taxes for the subsidiary entities that have C corporation status. For the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 , income taxes consisted of the following: 2019 2018 2017 Provision for income taxes: Current $ 69 $ 463 $ 2,762 Deferred 6,316 9,810 (23,107 ) Income tax expense (benefit) $ 6,385 $ 10,273 $ (20,345 ) The effective tax rate on pre-tax income differs from the U.S. statutory rate of 21% , 21% and 35% for 2019, 2018 and 2017, respectively, due to the following: 2019 2018 2017 Income tax expense (benefit) at federal statutory tax rate $ 19,947 $ 15,563 $ 39,797 Less: Income tax benefit at federal statutory tax rate for LLC entities (15,387 ) (13,863 ) (36,171 ) State and local income taxes 1,680 1,614 1,751 Permanent differences 13 (1,194 ) (630 ) Effective tax rate change (725 ) (1,148 ) (24,243 ) Unrecognized tax benefits 5,038 6,487 — Valuation allowance (2,478 ) 2,586 — Other (1,703 ) 228 (849 ) Income tax benefit $ 6,385 $ 10,273 $ (20,345 ) The following table summarizes the components of the net deferred income tax asset (liability) as December 28, 2019 and December 29, 2018 : 2019 2018 Deferred tax (liabilities) assets: Accelerated depreciation $ (60,216 ) $ (57,437 ) Net operating loss 18,036 22,915 Investment in limited partnership (17,686 ) (16,591 ) Net intangible assets (2,554 ) (1,734 ) Mining reclamation reserve 723 570 Working capital (e.g., accrued compensation, prepaid assets) 1,366 1,059 Interest expense limitation carryforward 2,691 2,586 Net deferred tax liabilities (57,640 ) (48,632 ) Less valuation allowance (1,675 ) (4,261 ) Net deferred tax liability $ (59,315 ) $ (52,893 ) The net deferred income tax liability as of December 28, 2019 and December 29, 2018 , are included in other noncurrent liabilities on the consolidated balance sheets. As of December 28, 2019 , Summit LLC had federal net operating loss carryforwards of $120.3 million , which expire between 2030 and 2037. Valuation Allowance —The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible (including the effect of available carryback and carryforward periods) and tax-planning strategies. The deferred income tax asset related to net operating losses resides with two separate tax paying subsidiaries (or subsidiary groups) of Summit LLC. These tax payers have historically generated taxable income and forecast to continue generating taxable income; however, the use of a portion of the net operating may be limited. 2019 2018 Valuation Allowance: Beginning balance $ (4,261 ) $ (1,675 ) Current year decreases (increases) from operations 2,586 (2,586 ) Ending balance $ (1,675 ) $ (4,261 ) On December 22, 2017, the Tax Cuts and Jobs Act of 2017 (“TCJA”) was enacted. Among other things, the TCJA, beginning January 1, 2018, reduced the federal statutory rate from 35% to 21% and extended bonus depreciation provisions. In addition, the TCJA prescribes the application of net operating loss carryforwards generated in 2018 and beyond will be limited, 100% asset expensing will be allowed through 2022 and begin to phase out in 2023, and the amount of interest expense we are able deduct may also be limited in future years. The TCJA contains many provisions which continue to be clarified through new regulations. As permitted by Staff Accounting Bulletin 118 issued by the SEC on December 22, 2017, we completed our accounting of the impacts of the TCJA. We have completed our analysis within 2018 consistent with the guidance of SAB 118 and any adjustments during the measurement period have been included in net earnings from continuing operations as an adjustment to income tax expense. As such, in the fourth quarter of 2018, the Company recorded additional tax expense of $2.6 million resulting from the IRS interpretative guidance of TCJA. As of December 28, 2019 and December 29, 2018 , a $1.7 million and $4.3 million , respectively, valuation allowance has been recorded on net deferred tax assets where realization of our net operating losses are not more likely than not. The Company has recognized a reserve against the deferred tax assets for unrecognized tax benefits in the amount of $11.6 million and $6.5 million as of December 28, 2019 and December 29, 2018 , respectively. The Company records interest and penalties as a component of the income tax provision. No material interest or penalties were recognized in income tax expense during the years ended December 28, 2019 and December 29, 2018 . A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: Unrealized Tax Benefits Balance—December 30, 2017 $ — Additions based on tax position in 2018 6,487 Balance—December 29, 2018 $ 6,487 Additions based on tax position in 2019 5,132 Balance—December 28, 2019 $ 11,619 Tax years from 2014 to 2019 remain open and subject to audit by federal, Canadian, and state tax authorities. No income tax expense or benefit was recognized in other comprehensive loss in 2019, 2018 or 2017. 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 applicable to a corporate resident in New York, New York. No material distributions were made in the years ended December 28, 2019 and December 29, 2018

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 28, 2019
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 income per share: 2019 2018 2017 Net income attributable to Summit Inc. $ 59,066 $ 33,906 $ 121,830 Weighted average shares of Class A stock outstanding 112,204,067 111,380,175 108,696,438 Basic earnings per share $ 0.53 $ 0.30 $ 1.12 Diluted net income attributable to Summit Inc. $ 59,066 $ 33,906 $ 121,830 Weighted average shares of Class A stock outstanding 112,204,067 111,380,175 108,696,438 Add: stock options 87,290 282,329 308,355 Add: warrants 4,206 25,049 42,035 Add: restricted stock units 342,620 459,280 308,221 Add: performance stock units 46,535 169,813 135,849 Weighted average dilutive shares outstanding 112,684,718 112,316,646 109,490,898 Diluted earnings per share $ 0.52 $ 0.30 $ 1.11 Excluded from the above calculations were the shares noted below as they were antidilutive: 2019 2018 2017 Antidilutive shares: LP Units 3,372,706 3,512,669 4,371,705

Stockholder's Equity_Members' I

Stockholder's Equity/Members' Interest	12 Months Ended
	Dec. 28, 2019
Schedule of Capitalization, Equity [Line Items]
Stockholder's Equity	Stockholders’ Equity Our capital stock consists of 1.0 billion shares of $0.01 par value Class A common stock authorized, of which 113,309,385 shares were issued and outstanding as of December 28, 2019 . We also have authorized 250 million shares of $0.01 par value Class B common stock, of which 99 shares were issued and outstanding as of December 28, 2019 . The Class B common stock entitles holders thereof, who are also holders of LP Units, with a number of votes that is equal to the number of LP Units they hold. The Class B common stock does not participate in dividends and does not have any liquidation rights. Equity Offerings —On January 10, 2017, Summit Inc. raised $237.6 million , net of underwriting discounts, through the issuance of 10,000,000 shares of Class A common stock at a public offering price of $24.05 per share. Summit Inc. used these proceeds to purchase an equal number of LP Units. From time to time, limited partners of Summit Holdings exchange 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. Shares (Class A) LP Units Total Summit Inc. Ownership Percentage Balance — December 30, 2017 110,350,594 3,689,620 114,040,214 96.8 % Exchanges during period 254,102 (254,102 ) — Stock option exercises 863,898 — 863,898 Other equity transactions 190,333 — 190,333 Balance — December 29, 2018 111,658,927 3,435,518 115,094,445 97.0 % Exchanges during period 185,861 (185,861 ) — Stock option exercises 1,065,446 — 1,065,446 Other equity transactions 399,151 — 399,151 Balance — December 28, 2019 113,309,385 3,249,657 116,559,042 97.2 % 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 income (loss) Balance — December 30, 2017 $ 2,364 $ 4,637 $ 385 $ 7,386 Postretirement liability adjustment, net of tax 1,209 — — 1,209 Foreign currency translation adjustment, net of tax — (6,784 ) — (6,784 ) Income on cash flow hedges, net of tax — — 870 870 Balance — December 29, 2018 $ 3,573 $ (2,147 ) $ 1,255 $ 2,681 Postretirement liability adjustment, net of tax (1,402 ) — — (1,402 ) Foreign currency translation adjustment, net of tax — 3,424 — 3,424 Loss on cash flow hedges, net of tax — — (1,255 ) (1,255 ) Balance — December 28, 2019 $ 2,171 $ 1,277 $ — $ 3,448
Summit Materials, LLC
Schedule of Capitalization, Equity [Line Items]
Members' Interest	Members’ Interest 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”) 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. Summit Inc.’s Equity Offerings — On January 10, 2017, Summit Inc. raised $237.6 million , net of underwriting discounts, through the issuance of 10,000,000 shares of Class A common stock at a public offering price of $24.05 per share. Summit Inc. used these proceeds to purchase an equal number of LP Units. 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 income (loss) Balance — December 30, 2017 $ (6,053 ) $ (10,022 ) $ (1,060 ) $ (17,135 ) Postretirement liability adjustment 1,661 — — 1,661 Foreign currency translation adjustment — (9,348 ) — (9,348 ) Income on cash flow hedges — — 1,206 1,206 Balance — December 29, 2018 $ (4,392 ) $ (19,370 ) $ 146 $ (23,616 ) Postretirement liability adjustment (1,925 ) — — (1,925 ) Foreign currency translation adjustment — 4,716 — 4,716 Loss on cash flow hedges — — (146 ) (146 ) Balance — December 28, 2019 $ (6,317 ) $ (14,654 ) $ — $ (20,971 )

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Dec. 28, 2019
Schedule Of Cash Flow Supplemental [Line Items]
Supplemental Cash Flow Information	Supplemental Cash Flow Information Supplemental cash flow information for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 was as follows: 2019 2018 2017 Cash payments: Interest $ 104,614 $ 103,250 $ 96,320 (Refund) payments for income taxes, net (919 ) 3,340 1,711 Operating cash payments on operating leases 10,618 N/A N/A Operating cash payments on finance leases 3,051 N/A N/A Finance cash payments on finance leases 13,164 N/A N/A Non cash financing activities: Purchase of noncontrolling interest $ — $ — $ (716 ) Stock Dividend — — (45,023 ) Right of use assets obtained in exchange for operating lease obligations 5,842 N/A N/A Right of use assets obtained in exchange for finance leases obligations 23,965 N/A N/A Exchange of LP Units to shares of Class A common stock 3,847 7,499 41,126
Summit Materials, LLC
Schedule Of Cash Flow Supplemental [Line Items]
Supplemental Cash Flow Information	Supplemental Cash Flow Information Supplemental cash flow information for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 was as follows: 2019 2018 2017 Cash payments: Interest $ 104,614 $ 103,250 $ 96,320 (Refund) payments for income taxes, net (919 ) 3,340 1,711 Operating cash payments on operating leases 10,618 N/A N/A Operating cash payments on finance leases 3,051 N/A N/A Finance cash payments on finance leases 13,164 N/A N/A Non cash financing activities: Right of use assets obtained in exchange for operating lease obligations $ 5,842 N/A N/A Right of use assets obtained in exchange for finance leases obligations 23,965 N/A N/A Purchase of noncontrolling interest — — (716 )

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 28, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-Based Compensation	Stock-Based Compensation Prior to the IPO and related Reorganization, the capital structure of Summit Holdings consisted of six different classes of limited partnership units, each of which was subject to unique distribution rights. In connection with the IPO and the related Reorganization, the limited partnership agreement of Summit Holdings was amended and restated to, among other things, modify its capital structure by creating LP Units. Holders of the LP Units periodically exchange their LP Units for shares of Class A common Stock of Summit Inc. In the first quarter of 2018, the Board of Directors vested the time-vesting units outstanding and we recognized the remaining $1.0 million of stock based compensation related to these LP units. Omnibus Incentive Plan In 2015, our Board of Directors and stockholders adopted the Summit Materials, Inc. 2015 Omnibus Incentive Plan (the "Plan"), which allows for grants of equity-based awards in the form of stock options, stock appreciation rights, restricted stock and restricted stock units, performance units, and other stock-based awards. The Plan authorizes the issuance of up to 13,500,000 shares of Class A common stock in the form of restricted stock units and stock options, of which 5.6 million shares were available for future grants as of December 28, 2019 . Restricted Stock Restricted Stock with Service-Based Vesting—Under the Plan, the Compensation Committee of the Board of Directors (the “Compensation Committee”) has granted restricted stock to members of the Board of Directors, executive officers and other key employees. These awards contain service conditions associated with continued employment or service. The terms of the restricted stock provide voting and regular dividend rights to holders of the awards. Upon vesting, the restrictions on the restricted stock lapse and the shares are considered issued and outstanding for accounting purposes. In each of 2019 , 2018 and 2017 , the Compensation Committee granted restricted stock to executives and key employees under the Plan as part of our annual equity award program, which vest over a two or three year period, subject to continued employment or service. From time to time, the Compensation Committee grants restricted stock to newly hired or promoted employees or other employees or consultants who have achieved extraordinary personal performance objectives. Further, in each of 2019 , 2018 and 2017 , the Compensation Committee granted 65,144 , 38,232 and 34,928 shares, respectively, to non-employee members of the Board of Directors for their annual service as directors. These restricted stock grants vest over a one year period. In measuring compensation expense associated with the grant of restricted stock, we use the fair value of the award, determined as the closing stock price for our common stock on the date of grant. Compensation expense is recorded monthly over the vesting period of the award. Restricted stock with Service- and Market-Condition-Based Vesting—In 2019, 2018 and 2017, the Compensation Committee granted restricted stock to certain members of our executive team as part of their annual compensation package. The restricted stock vests at the end of a three year performance period, based on our total stock return (“TSR”) ranking relative to companies in the S&P Building & Construction Select Industry Index, subject to continued employment. Compensation expense is recorded monthly over the vesting period of the awards. The following table summarizes information for the equity awards granted in 2019 : Options Restricted Stock Units Performance Stock Units Warrants Weighted Weighted Weighted Weighted average grant- Number of average grant- Number of average grant- average grant- Number of date fair value restricted date fair value performance date fair value Number of date fair value options per unit stock units per unit stock units per unit warrants per unit Beginning balance—December 29, 2018 3,267,149 $ 9.09 924,308 $ 24.57 295,252 $ 29.12 100,037 $ 18.00 Granted — — 1,238,530 17.60 242,007 26.20 — — Forfeited/ Canceled (73,596 ) 10.62 (176,152 ) 22.21 (146,614 ) 20.17 — — Exercised (1,065,446 ) 8.93 — — — — — — Vested — — (430,050 ) 23.71 — — — — Balance—December 28, 2019 2,128,107 $ 9.08 1,556,636 $ 21.17 390,645 $ 26.17 100,037 $ 18.00 The fair value of the time-vesting options granted was estimated as of the grant date using the Black-Scholes-Merton model, which requires the input of subjective assumptions, including the expected volatility and the expected term. The fair value of the performance stock units granted was estimated as of the grant date using Monte Carlo simulations, which requires the input of subjective assumptions, including the expected volatility and the expected term. The following table presents the weighted average assumptions used to estimate the fair value of grants in 2019, 2018 and 2017 . No options to purchase common stock were granted in 2019 or 2018 : Options Performance Stock Units 2017 2019 2018 2017 Risk-free interest rate 2.06% - 2.31% 2.49% 2.38% 1.45% Dividend yield N/A N/A N/A N/A Volatility 47% 36% 38% 39% Expected term 7 years 3 years 3 years 3 years The risk-free rate is based on the yield at the date of grant of a U.S. Treasury security with a maturity period approximating the expected term. As Summit Holdings has not historically and does not plan to issue regular dividends, a dividend yield of zero was used. The volatility assumption is based on reported data of a peer group of publicly traded companies for which historical information was available adjusted for the Company’s capital structure. The expected term is based on expectations about future exercises and represents the period of time that the units granted are expected to be outstanding. Compensation expense for time-vesting interests granted is based on the grant date fair value. The Company recognizes compensation costs on a straight-line basis over the service period, which is generally the vesting period of the award. Forfeitures are recognized as they occur. Share-based compensation expense, which is recognized in general and administrative expenses, totaled $20.4 million , $25.4 million and $49.9 million in the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 , respectively. As of December 28, 2019 , unrecognized compensation cost totaled $26.3 million . The weighted average remaining contractual term over which the unrecognized compensation cost is to be recognized is 1.8 years as of year-end 2019 . As of December 28, 2019 , the intrinsic value of outstanding options, restricted stock units and performance stock units was $10.7 million , $37.1 million and $9.3 million , respectively, and the remaining contractual term was 5.5 years , 1.0 years and 1.5 years , respectively. The weighted average strike price of stock options outstanding as of December 28, 2019 was $18.81 per share. The intrinsic value of 2.0 million exercisable stock options as of December 28, 2019 was $10.7 million with a weighted average strike price of $18.54 and a weighted average remaining vesting period of 5.5 years .
Summit Materials, LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-Based Compensation	Stock-Based Compensation Prior to the IPO and related Reorganization, the capital structure of Summit Holdings consisted of six different classes of limited partnership units, each of which was subject to unique distribution rights. In connection with the IPO and the related Reorganization, the limited partnership agreement of Summit Holdings was amended and restated to, among other things, modify its capital structure by creating LP Units. Holders of the LP Units periodically exchange their LP Units for shares of Class A common Stock of Summit Inc. In the first quarter of 2018, the Board of Directors vested the time-vesting units outstanding and we recognized the remaining $1.0 million of stock based compensation related to these LP units. Omnibus Incentive Plan In 2015, our Board of Directors and stockholders adopted the Summit Materials, Inc. 2015 Omnibus Incentive Plan (the "Plan"), which allows for grants of equity-based awards in the form of stock options, stock appreciation rights, restricted stock and restricted stock units, performance units, and other stock-based awards. The Plan authorizes the issuance of up to 13,500,000 shares of Class A common stock in the form of restricted stock units and stock options, of which 5.6 million shares were available for future grants as of December 28, 2019 . Restricted Stock Restricted Stock with Service-Based Vesting —Under the Plan, the Compensation Committee of the Board of Directors (the “Compensation Committee”) has granted restricted stock to members of the Board of Directors, executive officers and other key employees. These awards contain service conditions associated with continued employment or service. The terms of the restricted stock provide voting and regular dividend rights to holders of the awards. Upon vesting, the restrictions on the restricted stock lapse and the shares are considered issued and outstanding for accounting purposes. In each of 2019, 2018 and 2017, the Compensation Committee granted restricted stock to executives and key employees under the Plan as part of our annual equity award program, which vest over a two or three year period, subject to continued employment or service. From time to time, the Compensation Committee grants restricted stock to newly hired or promoted employees or other employees or consultants who have achieved extraordinary personal performance objectives. Further, in each of 2019, 2018 and 2017, the Compensation Committee granted 65,144 , 38,232 and 34,928 shares, respectively, to non-employee members of the Board of Directors for their annual service as directors. These restricted stock grants vest over a one year period. In measuring compensation expense associated with the grant of restricted stock, we use the fair value of the award, determined as the closing stock price for our common stock on the date of grant. Compensation expense is recorded monthly over the vesting period of the award. Restricted stock with Service- and Market-Condition-Based Vesting —In 2019, 2018 and 2017, the Compensation Committee granted restricted stock to certain members of our executive team as part of their annual compensation package. The restricted stock vests at the end of a three year performance period, based on our total stock return (“TSR”) ranking relative to companies in the S&P Building & Construction Select Industry Index, subject to continued employment. Compensation expense is recorded monthly over the vesting period of the awards. The following table summarizes information for the equity awards granted in 2019: Options Restricted Stock Units Performance Stock Units Warrants Weighted Weighted Weighted Weighted average grant- Number of average grant- Number of average grant- average grant- Number of date fair value restricted date fair value performance date fair value Number of date fair value options per unit stock units per unit stock units per unit warrants per unit Beginning balance—December 29, 2018 3,267,149 $ 9.09 924,308 $ 24.57 295,252 $ 29.12 100,037 $ 18.00 Granted — — 1,238,530 17.60 242,007 26.20 — — Forfeited/ Canceled (73,596 ) 10.62 (176,152 ) 22.21 (146,614 ) 20.17 — — Exercised (1,065,446 ) 8.93 — — — — — — Vested — — (430,050 ) 23.71 — — — — Balance—December 28, 2019 2,128,107 $ 9.08 1,556,636 $ 21.17 390,645 $ 26.17 100,037 $ 18.00 The fair value of the time-vesting options granted was estimated as of the grant date using the Black-Scholes-Merton model, which requires the input of subjective assumptions, including the expected volatility and the expected term. The fair value of the performance stock units granted was estimated as of the grant date using Monte Carlo simulations, which requires the input of subjective assumptions, including the expected volatility and the expected term. The following table presents the weighted average assumptions used to estimate the fair value of grants in 2019, 2018 and 2017. No options to purchase common stock were granted in 2019 or 2018: Options Performance Stock Units 2017 2019 2018 2017 Risk-free interest rate 2.06% - 2.31% 2.49% 2.38% 1.45% Dividend yield N/A N/A N/A N/A Volatility 47% 36% 38% 39% Expected term 7 years 3 years 3 years 3 years The risk-free rate is based on the yield at the date of grant of a U.S. Treasury security with a maturity period approximating the expected term. As Summit Holdings has not historically and does not plan to issue regular dividends, a dividend yield of zero was used. The volatility assumption is based on reported data of a peer group of publicly traded companies for which historical information was available adjusted for the Company’s capital structure. The expected term is based on expectations about future exercises and represents the period of time that the units granted are expected to be outstanding. Compensation expense for time-vesting interests granted is based on the grant date fair value. The Company recognizes compensation costs on a straight-line basis over the service period, which is generally the vesting period of the award. Forfeitures are recognized as they occur. Share-based compensation expense, which is recognized in general and administrative expenses, totaled $20.4 million , $25.4 million and $49.9 million in the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 , respectively. As of December 28, 2019 , unrecognized compensation cost totaled $26.3 million . The weighted average remaining contractual term over which the unrecognized compensation cost is to be recognized is 1.8 years as of year-end 2019. As of December 28, 2019 , the intrinsic value of outstanding options, restricted stock units and performance stock units was $10.7 million , $37.1 million and $9.3 million , respectively, and the remaining contractual term was 5.5 years , 1.0 years and 1.5 years , respectively. The weighted average strike price of stock options outstanding as of December 28, 2019 was $18.81 per share. The intrinsic value of 2.0 million exercisable stock options as of December 28, 2019 was $10.7 million with a weighted average strike price of $18.54 and a weighted average remaining vesting period of 5.5 years .

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 28, 2019
Defined Benefit Plan Disclosure [Line Items]
Employee Benefit Plans	Employee Benefit Plans Defined Contribution Plan —The Company sponsors employee 401(k) savings plans for its employees, including certain union employees. The plans provide for various required and discretionary Company matches of employees’ eligible compensation contributed to the plans. The expense for the defined contribution plans was $11.7 million , $11.2 million and $9.3 million for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 , respectively. Defined Benefit and Other Postretirement Benefits Plans —The Company’s subsidiary, Continental Cement, sponsors two noncontributory defined benefit pension plans for hourly and salaried employees. The plans are closed to new participants and benefits are frozen. As a result of the collective bargaining unit negotiations in 2017, the hourly defined benefit pension plan was amended to stop future benefit accruals for the Davenport employees effective December 31, 2017. Pension benefits for eligible hourly employees are based on a monthly pension factor for each year of credited service. Pension benefits for eligible salaried employees are generally based on years of service and average eligible compensation. Continental Cement also sponsors two unfunded healthcare and life insurance benefits plans for certain eligible retired employees. Effective January 1, 2014, the plan covering employees of the Hannibal, Missouri location was amended to eliminate all future retiree health and life coverage for current employees. During 2015, Continental Cement adopted one new unfunded healthcare plan to provide benefits prior to Medicare eligibility for certain hourly employees of the Davenport, Iowa location. As a result of the collective bargaining unit negotiations in 2017, hourly Davenport employees hired on or after January 1, 2018 are no longer eligible for retiree medical benefits. The funded status of the pension and other postretirement benefit plans is recognized in the consolidated balance sheets as the difference between the fair value of plan assets and the benefit obligations. For defined benefit pension plans, the benefit obligation is the projected benefit obligation (“PBO”) and for the healthcare and life insurance benefits plans, the benefit obligation is the accumulated postretirement benefit obligation (“APBO”). The PBO represents the actuarial present value of benefits expected to be paid upon retirement based on estimated future compensation levels. However, since the plans’ participants are not subject to future compensation increases, the plans’ PBO equals the accumulated benefit obligation (“ABO”). The APBO represents the actuarial present value of postretirement benefits attributed to employee services already rendered. The fair value of plan assets represents the current market value of assets held by an irrevocable trust fund for the sole benefit of participants. The measurement of the benefit obligations is based on the Company’s estimates and actuarial valuations. These valuations reflect the terms of the plan and use participant-specific information, such as compensation, age and years of service, as well as certain assumptions that require significant judgment, including estimates of discount rates, expected return on plan assets, rate of compensation increases, interest-crediting rates and mortality rates. The Company uses December 31 as the measurement date for its defined benefit pension and other postretirement benefit plans. Obligations and Funded Status —The following information is as of December 28, 2019 and December 29, 2018 and for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 : 2019 2018 Pension Healthcare Pension Healthcare benefits & Life Ins. benefits & Life Ins. Change in benefit obligations: Beginning of period $ 24,203 $ 9,203 $ 27,984 $ 9,793 Service cost 60 166 67 170 Interest cost 928 321 898 317 Actuarial (gain) loss 2,571 165 (3,136 ) (173 ) Benefits paid (1,581 ) (765 ) (1,610 ) (904 ) End of period $ 26,181 $ 9,090 $ 24,203 $ 9,203 Change in fair value of plan assets: Beginning of period $ 17,449 $ — $ 19,012 $ — Actual return on plan assets 2,055 — (551 ) — Employer contributions 319 765 598 904 Benefits paid (1,581 ) (765 ) (1,610 ) (904 ) End of period $ 18,242 $ — $ 17,449 $ — Funded status of plans $ (7,939 ) $ (9,090 ) $ (6,754 ) $ (9,203 ) Current liabilities $ — $ (653 ) $ — $ (687 ) Noncurrent liabilities (7,939 ) (8,437 ) (6,754 ) (8,516 ) Liability recognized $ (7,939 ) $ (9,090 ) $ (6,754 ) $ (9,203 ) Amounts recognized in accumulated other comprehensive income: Net actuarial (gain) loss $ 9,286 $ 2,121 $ 7,728 $ 1,995 Prior service cost — (1,931 ) — (2,172 ) Total amount recognized $ 9,286 $ 190 $ 7,728 $ (177 ) The amount recognized in accumulated other comprehensive income (“AOCI”) is the actuarial loss (credit) and prior service cost, which has not yet been recognized in periodic benefit cost. 2019 2018 2017 Pension Healthcare Pension Healthcare Pension Healthcare benefits & Life Ins. benefits & Life Ins. benefits & Life Ins. Amounts recognized in other comprehensive (income) loss: Net actuarial loss (gain) $ 1,760 $ 165 $ (1,300 ) $ (172 ) $ 1,068 $ (338 ) Prior service cost — — — — — (572 ) Amortization of prior year service cost — 241 — 241 — 168 Curtailment benefit — — — — (429 ) — Amortization of gain (202 ) (39 ) (312 ) (118 ) (547 ) (64 ) Adjustment to plan benefits — — — — — (414 ) Total amount recognized $ 1,558 $ 367 $ (1,612 ) $ (49 ) $ 92 $ (1,220 ) Components of net periodic benefit cost: Service cost $ 60 $ 166 $ 67 $ 170 $ 285 $ 184 Interest cost 928 321 898 317 998 365 Amortization of gain 202 39 312 118 547 64 Expected return on plan assets (1,244 ) — (1,284 ) — (1,302 ) — Amortization of prior service credit — (241 ) — (241 ) — (168 ) Net periodic (expense) benefit cost $ (54 ) $ 285 $ (7 ) $ 364 $ 528 $ 445 Assumptions— Weighted-average assumptions used to determine the benefit obligations as of year-end 2019 and 2018 are: 2019 2018 Healthcare Healthcare Pension benefits & Life Ins. Pension benefits & Life Ins. Discount rate 2.78% - 2.96% 2.73% - 2.79% 3.90% - 4.02% 3.87% - 3.91% Expected long-term rate of return on plan assets 7.00% N/A 7.00% N/A Weighted-average assumptions used to determine net periodic benefit cost for years ended December 28, 2019 , December 29, 2018 and December 30, 2017 : 2019 2018 2017 Healthcare Healthcare Healthcare Pension benefits & Life Ins. Pension benefits & Life Ins. Pension benefits & Life Ins. Discount rate 3.90% - 4.02% 3.87% - 3.91% 3.23% - 3.37% 3.20% - 3.25% 3.61% - 3.81% 3.54% - 3.65% Expected long-term rate of return on plan assets 7.00% N/A 7.00% N/A 7.00% N/A The expected long-term return on plan assets is based upon the Plans’ consideration of historical and forward-looking returns and the Company’s estimation of what a portfolio, with the target allocation described below, will earn over a long-term horizon. The discount rate is derived using the FTSE Pension Discount Curve. Assumed health care cost trend rates were 8.0% grading to 8.0% as of year-end 2019 and 2018 . Assumed health care cost trend rates have a significant effect on the amounts reported for the Company’s healthcare and life insurance benefits plans. A one percentage-point change in assumed health care cost trend rates would have the following effects as of year-end 2019 and 2018 : 2019 2018 Increase Decrease Increase Decrease Total service cost and interest cost components $ 30 $ (26 ) $ 31 $ (27 ) APBO 773 (678 ) 765 (690 ) Plan Assets —The defined benefit pension plans’ (the “Plans”) investment strategy is to minimize investment risk while generating acceptable returns. The Plans currently invest a relatively high proportion of the plan assets in fixed income securities, while the remainder is invested in equity securities, cash reserves and precious metals. The equity securities are diversified into funds with growth and value investment strategies. The target allocation for plan assets is as follows: equity securities— 30% ; fixed income securities— 63% ; cash reserves— 5% ; and precious metals— 2% . The Plans’ current investment allocations are within the tolerance of the target allocation. The Company had no Level 3 investments as of or for the years ended December 28, 2019 and December 29, 2018 . At year-end 2019 and 2018 , the Plans’ assets were invested predominantly in fixed-income securities and publicly traded equities, but may invest in other asset classes in the future subject to the parameters of the investment policy. The Plans’ investments in fixed-income assets include U.S. Treasury and U.S. agency securities and corporate bonds. The Plans’ investments in equity assets include U.S. and international securities and equity funds. The Company estimates the fair value of the Plans’ assets using various valuation techniques and, to the extent available, quoted market prices in active markets or observable market inputs. The descriptions and fair value methodologies for the Plans’ assets are as follows: Fixed Income Securities —Corporate and government bonds are classified as Level 2 assets, as they are either valued at quoted market prices from observable pricing sources at the reporting date or valued based upon comparable securities with similar yields and credit ratings. Equity Securities —Equity securities are valued at the closing market price reported on a U.S. exchange where the security is actively traded and are therefore classified as Level 1 assets. Cash —The carrying amounts of cash approximate fair value due to the short-term maturity. Precious Metals— Precious metals are valued at the closing market price reported on a U.S. exchange where the security is actively traded and are therefore classified as Level 1 assets. The fair value of the Plans’ assets by asset class and fair value hierarchy level as of December 28, 2019 and December 29, 2018 are as follows: 2019 Quoted prices in active Total fair markets for identical Observable value assets (Level 1) inputs (Level 2) Fixed income securities: Intermediate—government $ 2,482 $ 2,482 $ — Intermediate—corporate 1,066 — 1,066 Short-term—government 1,387 1,387 — Short-term—corporate 3,173 — 3,173 International 1,387 — 1,387 Equity securities: U.S. Large cap value 1,225 1,225 — U.S. Large cap growth 1,167 1,167 — U.S. Mid cap value 581 581 — U.S. Mid cap growth 578 578 — U.S. Small cap value 583 583 — U.S. Small cap growth 593 593 — Managed Futures 340 — 340 International 1,174 386 788 Emerging Markets 394 394 — Commodities Broad Basket 1,118 362 756 Cash 994 994 — Total $ 18,242 $ 10,732 $ 7,510 2018 Quoted prices in active Total fair markets for identical Observable value assets (Level 1) inputs (Level 2) Fixed income securities: Intermediate—government $ 3,547 $ 3,547 $ — Intermediate—corporate 3,437 — 3,437 Short-term—government 756 756 — Short-term—corporate 957 — 957 International 1,143 — 1,143 Equity securities: U.S. Large cap value 978 978 — U.S. Large cap growth 976 976 — U.S. Mid cap value 471 471 — U.S. Mid cap growth 496 496 — U.S. Small cap value 463 463 — U.S. Small cap growth 474 474 — Managed Futures 355 — 355 International 1,004 329 675 Emerging Markets 362 362 — Commodities Broad Basket 1,048 388 660 Cash 982 982 — Total $ 17,449 $ 10,222 $ 7,227 Cash Flows —The Company expects to contribute approximately $1.1 million in 2020 to both its pension plans and to its healthcare and life insurance benefits plans. The estimated benefit payments for each of the next five years and the five-year period thereafter are as follows: Pension Healthcare and Life benefits Insurance Benefits 2020 $ 1,718 $ 653 2021 1,681 638 2022 1,680 628 2023 1,679 618 2024 1,635 630 2025 - 2029 7,671 3,211 Multiemployer Pension Plans — In 2018, The Company acquired Buildex, LLC and assumed its obligation to contribute to a number of multiemployer defined benefit pension plans under the terms of collective-bargaining agreements that cover its union-represented employees. The risks of participating in multiemployer pension plans are different from single-employer plans. Assets contributed to a multiemployer plan by one employer may be used to provide benefits to employees of other participating employers. If a participating employer ceases contributing to the plan, the unfunded obligations of the plan are the responsibility of the remaining participating employers. The Company's participation in these plans for the annual period ended December 31, 2019, is outlined in the table below. The ''EIN/Pension Plan Number" column provides the Employer Identification Number (EIN) and the three-digit plan number, if applicable. Unless otherwise noted, the most recent Pension Protection Act (PPA) zone status available in 2019 and 2018 is for the plan 's year end at December 31, 2018, and December 31, 2017, respectively. The zone status is based on information the Company received from the plan and is certified by the plan's actuary. Among other factors, plans in the red zone are generally less than 65% funded, plans in the yellow zone are less than 80% funded and plans in the green zone are at least 80% funded. The "FIP/RP Status Pending/Implemented" column indicates plans for which a financial improvement plan (FIP) or a rehabilitation plan (RP) is either pending or has been implemented. The "Surcharge Imposed" column indicates whether a surcharge has been imposed on contributions to the plan. The last column lists the expiration date(s) of the collective-bargaining agreement(s) to which the plans are subject. There have been no significant changes that affect the comparability of 2018 and 2017 contributions. Expiration Date of Pension Protection Act FIP/RP Status Contributions of Company Collective- Pension EIN/ Pension Zone Status Pending/ ($ in thousands) Surcharge Bargaining Trust Fund Plan Number 2019 2018 Implemented 2019 2018 Imposed Agreement Construction Industry Laborers Pension Fund 43-6060737/001 Green - as of December 31, 2018 Green - as of December 31, 2017 None $ 112 $ 115 No 3/31/2021 Operating Engineers Local 101 Pension Plan 43-6059213/001 Green - as of December 31, 2018 Green - as of December 31, 2017 None 23 26 No 3/31/2021 Total Contributions $ 135 $ 141 The Company was not listed as providing more than 5% of the total contributions for the Operating Engineers Local 101 Pension Plan for the plan years 2018 and 2017 per the plan's Form 5500. The Company did not provide over 5% of total contributions in 2018 or 2017 for the Construction Industry Laborers Pension Fund per the plan's Form 5500. As of the date of the filing of this annual report on Form 10-K, Forms 5500 were not available for the plan year ending December 31, 2019.
Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Employee Benefit Plans	Employee Benefit Plans Defined Contribution Plan —The Company sponsors employee 401(k) savings plans for its employees, including certain union employees. The plans provide for various required and discretionary Company matches of employees’ eligible compensation contributed to the plans. The expense for the defined contribution plans was $11.7 million , $11.2 million and $9.3 million for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 , respectively. Defined Benefit and Other Postretirement Benefits Plans —The Company’s subsidiary, Continental Cement, sponsors two noncontributory defined benefit pension plans for hourly and salaried employees. The plans are closed to new participants and benefits are frozen. As a result of the collective bargaining unit negotiations in 2017, the hourly defined benefit pension plan was amended to stop future benefit accruals for the Davenport employees effective December 31, 2017. Pension benefits for eligible hourly employees are based on a monthly pension factor for each year of credited service. Pension benefits for eligible salaried employees are generally based on years of service and average eligible compensation. Continental Cement also sponsors two unfunded healthcare and life insurance benefits plans for certain eligible retired employees. Effective January 1, 2014, the plan covering employees of the Hannibal, Missouri location was amended to eliminate all future retiree health and life coverage for current employees. During 2015, Continental Cement adopted one new unfunded healthcare plan to provide benefits prior to Medicare eligibility for certain hourly employees of the Davenport, Iowa location. As a result of the collective bargaining unit negotiations in 2017, hourly Davenport employees hired on or after January 1, 2018 are no longer eligible for retiree medical benefits. The funded status of the pension and other postretirement benefit plans is recognized in the consolidated balance sheets as the difference between the fair value of plan assets and the benefit obligations. For defined benefit pension plans, the benefit obligation is the projected benefit obligation (“PBO”) and for the healthcare and life insurance benefits plans, the benefit obligation is the accumulated postretirement benefit obligation (“APBO”). The PBO represents the actuarial present value of benefits expected to be paid upon retirement based on estimated future compensation levels. However, since the plans’ participants are not subject to future compensation increases, the plans’ PBO equals the accumulated benefit obligation (“ABO”). The APBO represents the actuarial present value of postretirement benefits attributed to employee services already rendered. The fair value of plan assets represents the current market value of assets held by an irrevocable trust fund for the sole benefit of participants. The measurement of the benefit obligations is based on the Company’s estimates and actuarial valuations. These valuations reflect the terms of the plan and use participant-specific information, such as compensation, age and years of service, as well as certain assumptions that require significant judgment, including estimates of discount rates, expected return on plan assets, rate of compensation increases, interest-crediting rates and mortality rates. The Company uses December 31 as the measurement date for its defined benefit pension and other postretirement benefit plans. Obligations and Funded Status —The following information is as of December 28, 2019 and December 29, 2018 and for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 : 2019 2018 Pension Healthcare Pension Healthcare benefits & Life Ins. benefits & Life Ins. Change in benefit obligations: Beginning of period $ 24,203 $ 9,203 $ 27,984 $ 9,793 Service cost 60 166 67 170 Interest cost 928 321 898 317 Actuarial (gain) loss 2,571 165 (3,136 ) (173 ) Benefits paid (1,581 ) (765 ) (1,610 ) (904 ) End of period $ 26,181 $ 9,090 $ 24,203 $ 9,203 Change in fair value of plan assets: Beginning of period $ 17,449 $ — $ 19,012 $ — Actual return on plan assets 2,055 — (551 ) — Employer contributions 319 765 598 904 Benefits paid (1,581 ) (765 ) (1,610 ) (904 ) End of period $ 18,242 $ — $ 17,449 $ — Funded status of plans $ (7,939 ) $ (9,090 ) $ (6,754 ) $ (9,203 ) Current liabilities $ — $ (653 ) $ — $ (687 ) Noncurrent liabilities (7,939 ) (8,437 ) (6,754 ) (8,516 ) Liability recognized $ (7,939 ) $ (9,090 ) $ (6,754 ) $ (9,203 ) Amounts recognized in accumulated other comprehensive income: Net actuarial (gain) loss $ 9,286 $ 2,121 $ 7,728 $ 1,995 Prior service cost — (1,931 ) — (2,172 ) Total amount recognized $ 9,286 $ 190 $ 7,728 $ (177 ) The amount recognized in accumulated other comprehensive income (“AOCI”) is the actuarial loss (credit) and prior service cost, which has not yet been recognized in periodic benefit cost. 2019 2018 2017 Pension Healthcare Pension Healthcare Pension Healthcare benefits & Life Ins. benefits & Life Ins. benefits & Life Ins. Amounts recognized in other comprehensive (income) loss: Net actuarial loss (gain) $ 1,760 $ 165 $ (1,300 ) $ (172 ) $ 1,068 $ (338 ) Prior service cost — — — — — (572 ) Amortization of prior year service cost — 241 — 241 — 168 Curtailment benefit — — — — (429 ) — Amortization of gain (202 ) (39 ) (312 ) (118 ) (547 ) (64 ) Adjustment to plan benefits — — — — — (414 ) Total amount recognized $ 1,558 $ 367 $ (1,612 ) $ (49 ) $ 92 $ (1,220 ) Components of net periodic benefit cost: Service cost $ 60 $ 166 $ 67 $ 170 $ 285 $ 184 Interest cost 928 321 898 317 998 365 Amortization of gain 202 39 312 118 547 64 Expected return on plan assets (1,244 ) — (1,284 ) — (1,302 ) — Amortization of prior service credit — (241 ) — (241 ) — (168 ) Net periodic (expense) benefit cost $ (54 ) $ 285 $ (7 ) $ 364 $ 528 $ 445 Assumptions— Weighted-average assumptions used to determine the benefit obligations as of year-end 2019 and 2018 are: 2019 2018 Healthcare Healthcare Pension benefits & Life Ins. Pension benefits & Life Ins. Discount rate 2.78% - 2.96% 2.73% - 2.79% 3.90% - 4.02% 3.87% - 3.91% Expected long-term rate of return on plan assets 7.00% N/A 7.00% N/A Weighted-average assumptions used to determine net periodic benefit cost for years ended December 28, 2019 , December 29, 2018 and December 30, 2017 : 2019 2018 2017 Healthcare Healthcare Healthcare Pension benefits & Life Ins. Pension benefits & Life Ins. Pension benefits & Life Ins. Discount rate 3.90% - 4.02% 3.87% - 3.91% 3.23% - 3.37% 3.20% - 3.25% 3.61% - 3.81% 3.54% - 3.65% Expected long-term rate of return on plan assets 7.00% N/A 7.00% N/A 7.00% N/A The expected long-term return on plan assets is based upon the Plans’ consideration of historical and forward-looking returns and the Company’s estimation of what a portfolio, with the target allocation described below, will earn over a long-term horizon. The discount rate is derived using the FTSE Pension Discount Curve. Assumed health care cost trend rates were 8.0% grading to 8.0% as of year-end 2019 and 2018 . Assumed health care cost trend rates have a significant effect on the amounts reported for the Company’s healthcare and life insurance benefits plans. A one percentage-point change in assumed health care cost trend rates would have the following effects as of year-end 2019 and 2018 : 2019 2018 Increase Decrease Increase Decrease Total service cost and interest cost components $ 30 $ (26 ) $ 31 $ (27 ) APBO 773 (678 ) 765 (690 ) Plan Assets —The defined benefit pension plans’ (the “Plans”) investment strategy is to minimize investment risk while generating acceptable returns. The Plans currently invest a relatively high proportion of the plan assets in fixed income securities, while the remainder is invested in equity securities, cash reserves and precious metals. The equity securities are diversified into funds with growth and value investment strategies. The target allocation for plan assets is as follows: equity securities— 30% ; fixed income securities— 63% ; cash reserves— 5% ; and precious metals— 2% . The Plans’ current investment allocations are within the tolerance of the target allocation. The Company had no Level 3 investments as of or for the years ended December 28, 2019 and December 29, 2018 . At year-end 2019 and 2018 , the Plans’ assets were invested predominantly in fixed-income securities and publicly traded equities, but may invest in other asset classes in the future subject to the parameters of the investment policy. The Plans’ investments in fixed-income assets include U.S. Treasury and U.S. agency securities and corporate bonds. The Plans’ investments in equity assets include U.S. and international securities and equity funds. The Company estimates the fair value of the Plans’ assets using various valuation techniques and, to the extent available, quoted market prices in active markets or observable market inputs. The descriptions and fair value methodologies for the Plans’ assets are as follows: Fixed Income Securities —Corporate and government bonds are classified as Level 2 assets, as they are either valued at quoted market prices from observable pricing sources at the reporting date or valued based upon comparable securities with similar yields and credit ratings. Equity Securities —Equity securities are valued at the closing market price reported on a U.S. exchange where the security is actively traded and are therefore classified as Level 1 assets. Cash —The carrying amounts of cash approximate fair value due to the short-term maturity. Precious Metals— Precious metals are valued at the closing market price reported on a U.S. exchange where the security is actively traded and are therefore classified as Level 1 assets. The fair value of the Plans’ assets by asset class and fair value hierarchy level as of December 28, 2019 and December 29, 2018 are as follows: 2019 Quoted prices in active Total fair markets for identical Observable value assets (Level 1) inputs (Level 2) Fixed income securities: Intermediate—government $ 2,482 $ 2,482 $ — Intermediate—corporate 1,066 — 1,066 Short-term—government 1,387 1,387 — Short-term—corporate 3,173 — 3,173 International 1,387 — 1,387 Equity securities: U.S. Large cap value 1,225 1,225 — U.S. Large cap growth 1,167 1,167 — U.S. Mid cap value 581 581 — U.S. Mid cap growth 578 578 — U.S. Small cap value 583 583 — U.S. Small cap growth 593 593 — Managed Futures 340 — 340 International 1,174 386 788 Emerging Markets 394 394 — Commodities Broad Basket 1,118 362 756 Cash 994 994 — Total $ 18,242 $ 10,732 $ 7,510 2018 Quoted prices in active Total fair markets for identical Observable value assets (Level 1) inputs (Level 2) Fixed income securities: Intermediate—government $ 3,547 $ 3,547 $ — Intermediate—corporate 3,437 — 3,437 Short-term—government 756 756 — Short-term—corporate 957 — 957 International 1,143 — 1,143 Equity securities: U.S. Large cap value 978 978 — U.S. Large cap growth 976 976 — U.S. Mid cap value 471 471 — U.S. Mid cap growth 496 496 — U.S. Small cap value 463 463 — U.S. Small cap growth 474 474 — Managed Futures 355 — 355 International 1,004 329 675 Emerging Markets 362 362 — Commodities Broad Basket 1,048 388 660 Cash 982 982 — Total $ 17,449 $ 10,222 $ 7,227 Cash Flows —The Company expects to contribute approximately $1.1 million in 2020 to both its pension plans and to its healthcare and life insurance benefits plans. The estimated benefit payments for each of the next five years and the five-year period thereafter are as follows: Pension Healthcare and Life benefits Insurance Benefits 2020 $ 1,718 $ 653 2021 1,681 638 2022 1,680 628 2023 1,679 618 2024 1,635 630 2025 - 2029 7,671 3,211 Multiemployer Pension Plans — In 2018, The Company acquired Buildex, LLC and assumed its obligation to contribute to a number of multiemployer defined benefit pension plans under the terms of collective-bargaining agreements that cover its union-represented employees. The risks of participating in multiemployer pension plans are different from single-employer plans. Assets contributed to a multiemployer plan by one employer may be used to provide benefits to employees of other participating employers. If a participating employer ceases contributing to the plan, the unfunded obligations of the plan are the responsibility of the remaining participating employers. The Company's participation in these plans for the annual period ended December 31, 2019, is outlined in the table below. The ''EIN/Pension Plan Number" column provides the Employer Identification Number (EIN) and the three-digit plan number, if applicable. Unless otherwise noted, the most recent Pension Protection Act (PPA) zone status available in 2019 and 2018 is for the plan 's year end at December 31, 2018, and December 31, 2017, respectively. The zone status is based on information the Company received from the plan and is certified by the plan's actuary. Among other factors, plans in the red zone are generally less than 65% funded, plans in the yellow zone are less than 80% funded and plans in the green zone are at least 80% funded. The "FIP/RP Status Pending/Implemented" column indicates plans for which a financial improvement plan (FIP) or a rehabilitation plan (RP) is either pending or has been implemented. The "Surcharge Imposed" column indicates whether a surcharge has been imposed on contributions to the plan. The last column lists the expiration date(s) of the collective-bargaining agreement(s) to which the plans are subject. There have been no significant changes that affect the comparability of 2018 and 2017 contributions. Expiration Date of Pension Protection Act FIP/RP Status Contributions of Company Collective- Pension EIN/ Pension Zone Status Pending/ ($ in thousands) Surcharge Bargaining Trust Fund Plan Number 2019 2018 Implemented 2019 2018 Imposed Agreement Construction Industry Laborers Pension Fund 43-6060737/001 Green - as of December 31, 2018 Green - as of December 31, 2017 None $ 112 $ 115 No 3/31/2021 Operating Engineers Local 101 Pension Plan 43-6059213/001 Green - as of December 31, 2018 Green - as of December 31, 2017 None 23 26 No 3/31/2021 Total Contributions $ 135 $ 141 The Company was not listed as providing more than 5% of the total contributions for the Operating Engineers Local 101 Pension Plan for the plan years 2018 and 2017 per the plan's Form 5500. The Company did not provide over 5% of total contributions in 2018 or 2017 for the Construction Industry Laborers Pension Fund per the plan's Form 5500. As of the date of the filing of this annual report on Form 10-K, Forms 5500 were not available for the plan year ending December 31, 2019.

Accrued Mining and Landfill Rec

Accrued Mining and Landfill Reclamation	12 Months Ended
	Dec. 28, 2019
Asset Retirement Obligations [Line Items]
Accrued Mining and Landfill Reclamation	Accrued Mining and Landfill Reclamation The Company has asset retirement obligations arising from regulatory or contractual requirements to perform certain reclamation activities at the time that certain quarries and landfills are closed, which are primarily included in other noncurrent liabilities on the consolidated balance sheets. The current portion of the liabilities, $7.9 million and $4.1 million as of December 28, 2019 and December 29, 2018 , respectively, is included in accrued expenses on the consolidated balance sheets. The total undiscounted anticipated costs for site reclamation as of December 28, 2019 and December 29, 2018 were $97.4 million and $92.5 million , respectively. The liabilities were initially measured at fair value and are subsequently adjusted for accretion expense, payments and changes in the amount or timing of the estimated cash flows. The corresponding asset retirement costs are capitalized as part of the carrying amount of the related long-lived asset and depreciated over the asset’s remaining useful life. The following table presents the activity for the asset retirement obligations for the years ended December 28, 2019 and December 29, 2018 : 2019 2018 Beginning balance $ 30,999 $ 24,329 Acquired obligations 805 3,937 Change in cost estimate 4,468 2,808 Settlement of reclamation obligations (1,812 ) (1,680 ) Accretion expense 2,216 1,605 Ending balance $ 36,676 $ 30,999
Summit Materials, LLC
Asset Retirement Obligations [Line Items]
Accrued Mining and Landfill Reclamation	Accrued Mining and Landfill Reclamation The Company has asset retirement obligations arising from regulatory or contractual requirements to perform certain reclamation activities at the time that certain quarries and landfills are closed, which are primarily included in other noncurrent liabilities on the consolidated balance sheets. The current portion of the liabilities, $7.9 million and $4.1 million as of December 28, 2019 and December 29, 2018 , respectively, is included in accrued expenses on the consolidated balance sheets. The total undiscounted anticipated costs for site reclamation as of December 28, 2019 and December 29, 2018 were $97.4 million and $92.5 million , respectively. The liabilities were initially measured at fair value and are subsequently adjusted for accretion expense, payments and changes in the amount or timing of the estimated cash flows. The corresponding asset retirement costs are capitalized as part of the carrying amount of the related long-lived asset and depreciated over the asset’s remaining useful life. The following table presents the activity for the asset retirement obligations for the years ended December 28, 2019 and December 29, 2018 : 2019 2018 Beginning balance $ 30,999 $ 24,329 Acquired obligations 805 3,937 Change in cost estimate 4,468 2,808 Settlement of reclamation obligations (1,812 ) (1,680 ) Accretion expense 2,216 1,605 Ending balance $ 36,676 $ 30,999

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 28, 2019
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 not able to predict the ultimate outcome or cost of the investigation at this time. 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. 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 not able to predict the ultimate outcome or cost of the investigation at this time. 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. 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

Leases

Leases	12 Months Ended
	Dec. 28, 2019
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: 2019 Operating lease cost $ 10,451 Variable lease cost 423 Short-term lease cost 38,417 Financing lease cost: Amortization of right-of-use assets 11,062 Interest on lease liabilities 3,171 Total lease cost $ 63,524 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 32,777 Current operating lease liabilities $ 8,427 Noncurrent operating lease liabilities 25,381 Total operating lease liabilities $ 33,808 Finance leases: Property and equipment, gross $ 82,660 Less accumulated depreciation (24,907 ) Property and equipment, net $ 57,753 Current finance lease liabilities $ 16,007 Long-term finance lease liabilities 40,410 Total finance lease liabilities $ 56,417 2019 Lease Term Discount Rate (years) (%) Weighted average: Operating leases 8.6 5.5 % Finance lease 2.6 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 $ 9,958 $ 18,646 2021 7,960 21,886 2022 4,852 14,940 2023 3,842 1,732 2024 2,246 2,252 Thereafter 14,292 2,829 Total lease payments 43,150 62,285 Less imputed interest (9,342 ) (5,868 ) Present value of lease payments $ 33,808 $ 56,417 The Company has lease agreements associated with quarry facilities under which royalty payments are made. The payments are generally based on tons sold in a particular period; however, certain agreements have minimum annual payments. Royalty expense recorded in cost of revenue during the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 was $24.3 million , $20.1 million and $18.7 million , respectively. Minimum contractual commitments for the subsequent five years under royalty agreements are as follows: Royalty Agreements 2020 $ 7,555 2021 7,212 2022 7,214 2023 7,216 2024 6,613
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: 2019 Operating lease cost $ 10,451 Variable lease cost 423 Short-term lease cost 38,417 Financing lease cost: Amortization of right-of-use assets 11,062 Interest on lease liabilities 3,171 Total lease cost $ 63,524 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 32,777 Current operating lease liabilities $ 8,427 Noncurrent operating lease liabilities 25,381 Total operating lease liabilities $ 33,808 Finance leases: Property and equipment, gross $ 82,660 Less accumulated depreciation (24,907 ) Property and equipment, net $ 57,753 Current finance lease liabilities $ 16,007 Long-term finance lease liabilities 40,410 Total finance lease liabilities $ 56,417 2019 Lease Term Discount Rate (years) (%) Weighted average: Operating leases 8.6 5.5 % Finance lease 2.6 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 $ 9,958 $ 18,646 2021 7,960 21,886 2022 4,852 14,940 2023 3,842 1,732 2024 2,246 2,252 Thereafter 14,292 2,829 Total lease payments 43,150 62,285 Less imputed interest (9,342 ) (5,868 ) Present value of lease payments $ 33,808 $ 56,417 The Company has lease agreements associated with quarry facilities under which royalty payments are made. The payments are generally based on tons sold in a particular period; however, certain agreements have minimum annual payments. Royalty expense recorded in cost of revenue during the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 was $24.3 million , $20.1 million and $18.7 million , respectively. Minimum contractual commitments for the subsequent five years under royalty agreements are as follows: Royalty Agreements 2020 $ 7,555 2021 7,212 2022 7,214 2023 7,216 2024 6,613
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: 2019 Operating lease cost $ 10,451 Variable lease cost 423 Short-term lease cost 38,417 Financing lease cost: Amortization of right-of-use assets 11,062 Interest on lease liabilities 3,171 Total lease cost $ 63,524 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 32,777 Current operating lease liabilities $ 8,427 Noncurrent operating lease liabilities 25,381 Total operating lease liabilities $ 33,808 Finance leases: Property and equipment, gross $ 82,660 Less accumulated depreciation (24,907 ) Property and equipment, net $ 57,753 Current finance lease liabilities $ 16,007 Long-term finance lease liabilities 40,410 Total finance lease liabilities $ 56,417 2019 Lease Term Discount Rate (years) (%) Weighted average: Operating leases 8.6 5.5 % Finance lease 2.6 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 $ 9,958 $ 18,646 2021 7,960 21,886 2022 4,852 14,940 2023 3,842 1,732 2024 2,246 2,252 Thereafter 14,292 2,829 Total lease payments 43,150 62,285 Less imputed interest (9,342 ) (5,868 ) Present value of lease payments $ 33,808 $ 56,417 The Company has lease agreements associated with quarry facilities under which royalty payments are made. The payments are generally based on tons sold in a particular period; however, certain agreements have minimum annual payments. Royalty expense recorded in cost of revenue during the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 was $24.3 million , $20.1 million and $18.7 million , respectively. Minimum contractual commitments for the subsequent five years under royalty agreements are as follows: Royalty Agreements 2020 $ 7,555 2021 7,212 2022 7,214 2023 7,216 2024 6,613
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: 2019 Operating lease cost $ 10,451 Variable lease cost 423 Short-term lease cost 38,417 Financing lease cost: Amortization of right-of-use assets 11,062 Interest on lease liabilities 3,171 Total lease cost $ 63,524 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 32,777 Current operating lease liabilities $ 8,427 Noncurrent operating lease liabilities 25,381 Total operating lease liabilities $ 33,808 Finance leases: Property and equipment, gross $ 82,660 Less accumulated depreciation (24,907 ) Property and equipment, net $ 57,753 Current finance lease liabilities $ 16,007 Long-term finance lease liabilities 40,410 Total finance lease liabilities $ 56,417 2019 Lease Term Discount Rate (years) (%) Weighted average: Operating leases 8.6 5.5 % Finance lease 2.6 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 $ 9,958 $ 18,646 2021 7,960 21,886 2022 4,852 14,940 2023 3,842 1,732 2024 2,246 2,252 Thereafter 14,292 2,829 Total lease payments 43,150 62,285 Less imputed interest (9,342 ) (5,868 ) Present value of lease payments $ 33,808 $ 56,417 The Company has lease agreements associated with quarry facilities under which royalty payments are made. The payments are generally based on tons sold in a particular period; however, certain agreements have minimum annual payments. Royalty expense recorded in cost of revenue during the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 was $24.3 million , $20.1 million and $18.7 million , respectively. Minimum contractual commitments for the subsequent five years under royalty agreements are as follows: Royalty Agreements 2020 $ 7,555 2021 7,212 2022 7,214 2023 7,216 2024 6,613

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 28, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Financial Instruments	Fair Value of Financial Instruments 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 Company had entered into interest rate derivatives on $200.0 million of its term loan borrowings to add stability to interest expense and to manage its exposure to interest rate movements. The interest rate derivative expired in September 2019. The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in accumulated other comprehensive income and will be subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. The fair value of contingent consideration and derivatives as of December 28, 2019 and December 29, 2018 was: 2019 2018 Current portion of acquisition-related liabilities and Accrued expenses: Contingent consideration $ 1,967 $ 1,394 Cash flow hedges — — Acquisition-related liabilities and Other noncurrent liabilities: Contingent consideration $ 1,302 $ 5,175 Cash flow hedges — — The fair value accounting guidance establishes the following fair value hierarchy that prioritizes the inputs used to measure fair value: Level 1 — Unadjusted quoted prices for identical assets or liabilities in active markets. Level 2 — Inputs other than Level 1 that are based on observable market data, either directly or indirectly. These include quoted prices for similar assets or liabilities in active markets, quoted prices for identical assets or liabilities in inactive markets, inputs that are observable that are not prices and inputs that are derived from or corroborated by observable markets. Level 3 — Valuations developed from unobservable data, reflecting the Company’s own assumptions, which market participants would use in pricing the asset or liability. The fair value of contingent consideration was based on unobservable, or Level 3, inputs, including projected probability-weighted cash payments and a 10.0% 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. The fair value of the cash flow hedges are based on observable, or Level 2, inputs such as interest rates, bond yields and prices in inactive markets. There were no material adjustments to the fair value of contingent consideration in 2019 or 2018 , or to cash flow hedges in 2019 or 2018 . 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 December 28, 2019 and December 29, 2018 were: December 28, 2019 December 29, 2018 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt(1) $ 1,918,720 $ 1,872,273 $ 1,777,722 $ 1,828,159 Level 3 Current portion of deferred consideration and noncompete obligations(2) 30,733 30,733 32,876 32,876 Long term portion of deferred consideration and noncompete obligations(3) 18,499 18,499 44,293 44,293 _____________________ (1) $7.9 million and $6.4 million were included in current portion of debt as of December 28, 2019 and December 29, 2018 , respectively. (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 of Financial Instruments	Fair Value of Financial Instruments 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 Company had entered into interest rate derivatives on $200.0 million of its term loan borrowings to add stability to interest expense and to manage its exposure to interest rate movements. The interest rate derivative expired in September 2019. The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in accumulated other comprehensive income and will be subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. The fair value of contingent consideration and derivatives as of December 28, 2019 and December 29, 2018 was: 2019 2018 Current portion of acquisition-related liabilities and Accrued expenses: Contingent consideration $ 1,967 $ 1,394 Cash flow hedges — — Acquisition-related liabilities and Other noncurrent liabilities: Contingent consideration $ 1,302 $ 5,175 Cash flow hedges — — The fair value accounting guidance establishes the following fair value hierarchy that prioritizes the inputs used to measure fair value: Level 1 — Unadjusted quoted prices for identical assets or liabilities in active markets. Level 2 — Inputs other than Level 1 that are based on observable market data, either directly or indirectly. These include quoted prices for similar assets or liabilities in active markets, quoted prices for identical assets or liabilities in inactive markets, inputs that are observable that are not prices and inputs that are derived from or corroborated by observable markets. Level 3 — Valuations developed from unobservable data, reflecting the Company’s own assumptions, which market participants would use in pricing the asset or liability. The fair value of contingent consideration was based on unobservable, or Level 3, inputs, including projected probability-weighted cash payments and a 10.0% 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. The fair value of the cash flow hedges are based on observable, or Level 2, inputs such as interest rates, bond yields and prices in inactive markets. There were no material adjustments to the fair value of contingent consideration in 2019 or 2018 , or to cash flow hedges in 2019 or 2018 . 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 December 28, 2019 and December 29, 2018 were: December 28, 2019 December 29, 2018 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt(1) $ 1,918,720 $ 1,872,273 $ 1,777,722 $ 1,828,159 Level 3 Current portion of deferred consideration and noncompete obligations(2) 28,233 28,233 30,376 30,376 Long term portion of deferred consideration and noncompete obligations(3) 16,364 16,364 40,179 40,179 ______________________ (1) $7.9 million and $6.4 million were included in current portion of debt as of December 28, 2019 and December 29, 2018 , respectively. (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	12 Months Ended
	Dec. 28, 2019
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, the Company’s Chief Operating Decision Maker (“CODM”). The CODM primarily evaluates the performance of its segments and allocates resources to them based on a segment profit metric that we call Adjusted EBITDA, which is computed as earnings from continuing 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 and for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 : 2019 2018 2017 Revenue*: West $ 1,122,338 $ 1,117,066 $ 998,843 East 809,098 703,147 629,919 Cement 290,704 280,789 303,813 Total revenue $ 2,222,140 $ 2,101,002 $ 1,932,575 ______________________ * Intercompany sales are immaterial and the presentation above only reflects sales to external customers. 2019 2018 2017 Income (loss) from operations before taxes $ 78,224 $ 96,077 $ (158,200 ) Interest expense 116,509 116,548 108,549 Depreciation, depletion and amortization 214,886 203,305 177,643 Accretion 2,216 1,605 1,875 Loss on debt financings 14,565 149 4,815 Tax receivable agreement expense (benefit) 16,237 (22,684 ) 271,016 Gain on sale of business — (12,108 ) — Transaction costs 2,222 4,238 7,733 Non-cash compensation 20,403 25,378 21,140 Other (3,800 ) (6,247 ) 1,206 Total Adjusted EBITDA $ 461,462 $ 406,261 $ 435,777 Total Adjusted EBITDA by Segment: West $ 204,964 $ 188,999 $ 203,590 East 187,625 138,032 139,108 Cement 103,438 111,394 127,547 Corporate and other (34,565 ) (32,164 ) (34,468 ) Total Adjusted EBITDA $ 461,462 $ 406,261 $ 435,777 2019 2018 2017 Purchases of property, plant and equipment West $ 71,397 $ 120,657 $ 83,591 East 77,894 64,384 68,556 Cement 25,691 28,036 35,803 Total reportable segments 174,982 213,077 187,950 Corporate and other 2,513 7,608 6,196 Total purchases of property, plant and equipment $ 177,495 $ 220,685 $ 194,146 2019 2018 2017 Depreciation, depletion, amortization and accretion: West $ 93,256 $ 91,794 $ 71,314 East 81,403 75,433 67,252 Cement 38,447 35,061 38,351 Total reportable segments 213,106 202,288 176,917 Corporate and other 3,996 2,622 2,601 Total depreciation, depletion, amortization and accretion $ 217,102 $ 204,910 $ 179,518 2019 2018 2017 Total assets: West $ 1,379,684 $ 1,370,501 $ 1,225,463 East 1,288,835 1,253,640 1,035,609 Cement 868,528 877,586 870,652 Total reportable segments 3,537,047 3,501,727 3,131,724 Corporate and other 530,509 355,914 655,609 Total $ 4,067,556 $ 3,857,641 $ 3,787,333
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, the Company’s Chief Operating Decision Maker (“CODM”). The CODM primarily evaluates the performance of its segments and allocates resources to them based on a segment profit metric that we call Adjusted EBITDA, which is computed as earnings from continuing 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 and for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 : 2019 2018 2017 Revenue*: West $ 1,122,338 $ 1,117,066 $ 998,843 East 809,098 703,147 629,919 Cement 290,704 280,789 303,813 Total revenue $ 2,222,140 $ 2,101,002 $ 1,932,575 ______________________ * Intercompany sales are immaterial and the presentation above only reflects sales to external customers. 2019 2018 2017 Income (loss) from operations before taxes $ 94,982 $ 74,110 $ 113,696 Interest expense 115,988 115,831 107,655 Depreciation, depletion and amortization 214,886 203,305 177,643 Accretion 2,216 1,605 1,875 Loss on debt financings 14,565 149 4,815 Gain on sale of business — (12,108 ) — Transaction costs 2,222 4,238 7,733 Non-cash compensation 20,403 25,378 21,140 Other (3,800 ) (6,247 ) 1,206 Total Adjusted EBITDA $ 461,462 $ 406,261 $ 435,763 Total Adjusted EBITDA by Segment: West $ 204,964 $ 188,999 $ 203,590 East 187,625 138,032 139,108 Cement 103,438 111,394 127,547 Corporate and other (34,565 ) (32,164 ) (34,482 ) Total Adjusted EBITDA $ 461,462 $ 406,261 $ 435,763 2019 2018 2017 Purchases of property, plant and equipment West $ 71,397 $ 120,657 $ 83,591 East 77,894 64,384 68,556 Cement 25,691 28,036 35,803 Total reportable segments 174,982 213,077 187,950 Corporate and other 2,513 7,608 6,196 Total purchases of property, plant and equipment $ 177,495 $ 220,685 $ 194,146 2019 2018 2017 Depreciation, depletion, amortization and accretion: West $ 93,256 $ 91,794 $ 71,314 East 81,403 75,433 67,252 Cement 38,447 35,061 38,351 Total reportable segments 213,106 202,288 176,917 Corporate and other 3,996 2,622 2,601 Total depreciation, depletion, amortization and accretion $ 217,102 $ 204,910 $ 179,518 2019 2018 2017 Total assets: West $ 1,379,684 $ 1,370,501 $ 1,225,463 East 1,288,835 1,253,640 1,035,609 Cement 868,528 877,586 870,652 Total reportable segments 3,537,047 3,501,727 3,131,724 Corporate and other 319,176 131,517 372,517 Total $ 3,856,223 $ 3,633,244 $ 3,504,241

Senior Notes' Guarantor and Non

Senior Notes' Guarantor and Non-Guarantor Financial Information	12 Months Ended
	Dec. 28, 2019
Summit Materials, LLC
Condensed Financial Statements, Captions [Line Items]
Senior Notes' Guarantor and Non-Guarantor Financial Information	Senior Notes’ 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. 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 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 Balance Sheets December 29, 2018 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Assets Current assets: Cash and cash equivalents $ 117,219 $ 8,440 $ 7,719 $ (4,870 ) $ 128,508 Accounts receivable, net — 199,538 15,165 (185 ) 214,518 Intercompany receivables 500,765 624,427 — (1,125,192 ) — Cost and estimated earnings in excess of billings — 17,711 891 — 18,602 Inventories — 210,149 3,702 — 213,851 Other current assets 1,953 11,308 2,800 — 16,061 Total current assets 619,937 1,071,573 30,277 (1,130,247 ) 591,540 Property, plant and equipment, net 13,300 1,709,083 57,749 — 1,780,132 Goodwill — 1,136,785 56,243 — 1,193,028 Intangible assets, net — 18,460 — — 18,460 Other assets 3,292,851 154,080 947 (3,397,794 ) 50,084 Total assets $ 3,926,088 $ 4,089,981 $ 145,216 $ (4,528,041 ) $ 3,633,244 Liabilities and Member’s Interest Current liabilities: Current portion of debt $ 6,354 $ — $ — $ — $ 6,354 Current portion of acquisition-related liabilities — 31,770 — — 31,770 Accounts payable 4,712 92,132 12,349 (185 ) 109,008 Accrued expenses 45,146 57,826 1,927 (4,870 ) 100,029 Intercompany payables 673,175 436,564 15,453 (1,125,192 ) — Billings in excess of costs and estimated earnings — 11,347 493 — 11,840 Total current liabilities 729,387 629,639 30,222 (1,130,247 ) 259,001 Long-term debt 1,807,502 — — — 1,807,502 Acquisition-related liabilities — 45,354 — — 45,354 Other noncurrent liabilities 3,768 226,137 77,368 (171,317 ) 135,956 Total liabilities 2,540,657 901,130 107,590 (1,301,564 ) 2,247,813 Total member's interest 1,385,431 3,188,851 37,626 (3,226,477 ) 1,385,431 Total liabilities and member’s interest $ 3,926,088 $ 4,089,981 $ 145,216 $ (4,528,041 ) $ 3,633,244 Condensed Consolidating Statements of Operations and Comprehensive Income Year Ended December 28, 2019 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 2,139,457 $ 94,879 $ (12,196 ) $ 2,222,140 Cost of revenue (excluding items shown separately below) — 1,473,124 65,404 (12,196 ) 1,526,332 General and administrative expenses 58,099 195,683 11,366 — 265,148 Depreciation, depletion, amortization and accretion 3,997 207,277 5,828 — 217,102 Operating (loss) income (62,096 ) 263,373 12,281 — 213,558 Other (income) loss, net (279,517 ) (8,767 ) (790 ) 291,662 2,588 Interest expense (income) 127,734 (16,561 ) 4,815 — 115,988 Income from operation before taxes 89,687 288,701 8,256 (291,662 ) 94,982 Income tax expense 1,090 3,377 1,918 — 6,385 Net income attributable to Summit LLC $ 88,597 $ 285,324 $ 6,338 $ (291,662 ) $ 88,597 Comprehensive income attributable to member of Summit Materials, LLC $ 91,242 $ 287,395 $ 1,622 $ (289,017 ) $ 91,242 Condensed Consolidating Statements of Operations and Comprehensive Income Year ended December 29, 2018 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 2,018,428 $ 88,658 $ (6,084 ) $ 2,101,002 Cost of revenue (excluding items shown separately below) — 1,416,222 65,641 (6,084 ) 1,475,779 General and administrative expenses 62,376 184,917 10,554 — 257,847 Depreciation, depletion, amortization and accretion 2,622 197,406 4,882 — 204,910 Operating (loss) income (64,998 ) 219,883 7,581 — 162,466 Other (income) loss, net (249,204 ) (14,643 ) 823 247,657 (15,367 ) Interest expense (income) 118,857 (7,818 ) 4,792 — 115,831 Gain on sale of business — (12,108 ) — — (12,108 ) Income from operation before taxes 65,349 254,452 1,966 (247,657 ) 74,110 Income tax expense 1,512 8,226 535 — 10,273 Net income attributable to Summit LLC $ 63,837 $ 246,226 $ 1,431 $ (247,657 ) $ 63,837 Comprehensive income attributable to member of Summit Materials, LLC $ 57,356 $ 243,359 $ 10,779 $ (254,138 ) $ 57,356 Condensed Consolidating Statements of Operations and Comprehensive Income Year ended December 30, 2017 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 1,854,434 $ 84,020 $ (5,879 ) $ 1,932,575 Cost of revenue (excluding items shown separately below) — 1,227,037 60,619 (5,879 ) 1,281,777 General and administrative expenses 63,954 178,023 8,426 — 250,403 Depreciation, depletion, amortization and accretion 2,601 172,738 4,179 — 179,518 Operating (loss) income (66,555 ) 276,636 10,796 — 220,877 Other (income) loss, net (307,876 ) (1,925 ) (533 ) 309,860 (474 ) Interest expense 105,735 (2,415 ) 4,335 — 107,655 Income from continuing operations before taxes 135,586 280,976 6,994 (309,860 ) 113,696 Income tax (benefit) expense 1,518 (23,774 ) 1,911 — (20,345 ) Net income 134,068 304,750 5,083 (309,860 ) 134,041 Net income attributable to noncontrolling interest — — — (27 ) (27 ) Net income attributable to member of Summit Materials, LLC $ 134,068 $ 304,750 $ 5,083 $ (309,833 ) $ 134,068 Comprehensive income attributable to member of Summit Materials, LLC $ 144,377 $ 302,209 $ (2,685 ) $ (299,524 ) $ 144,377 Condensed Consolidating Statements of Cash Flows For the year ended December 28, 2019 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Net cash (used in) provided by operating activities $ (112,019 ) $ 431,323 $ 17,880 $ — $ 337,184 Cash flow from investing activities: Acquisitions, net of cash acquired — (5,392 ) — — (5,392 ) Purchase of property, plant and equipment (2,513 ) (163,652 ) (11,330 ) — (177,495 ) Proceeds from the sale of property, plant, and equipment — 21,083 90 — 21,173 Other — (1,095 ) — — (1,095 ) Net cash used for investing activities (2,513 ) (149,056 ) (11,240 ) — (162,809 ) Cash flow from financing activities: Proceeds from investment by member (21,614 ) 40,690 — — 19,076 Net proceeds from debt issuance 300,000 — — — 300,000 Loans received from and payments made on loans from other Summit Companies 287,029 (280,836 ) (4,586 ) (1,607 ) — Payments on long-term debt (256,354 ) (13,650 ) (225 ) — (270,229 ) Payments on acquisition-related liabilities — (31,383 ) — — (31,383 ) Debt issuance costs (6,312 ) — — — (6,312 ) Distributions from partnership (2,500 ) — — — (2,500 ) Other (462 ) (40 ) — — (502 ) Net cash provided by (used in) financing activities 299,787 (285,219 ) (4,811 ) (1,607 ) 8,150 Impact of cash on foreign currency — — 286 — 286 Net increase (decrease) in cash 185,255 (2,952 ) 2,115 (1,607 ) 182,811 Cash — Beginning of period 117,219 8,440 7,719 (4,870 ) 128,508 Cash — End of period $ 302,474 $ 5,488 $ 9,834 $ (6,477 ) $ 311,319 Condensed Consolidating Statements of Cash Flows For the year ended December 29, 2018 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Net cash (used in) provided by operating activities $ (142,315 ) $ 340,401 $ 11,282 $ — $ 209,368 Cash flow from investing activities: Acquisitions, net of cash acquired — (246,017 ) — — (246,017 ) Purchase of property, plant and equipment (7,607 ) (188,435 ) (24,643 ) — (220,685 ) Proceeds from the sale of property, plant, and equipment — 21,263 372 — 21,635 Proceeds from the sale of a business — 21,564 — — 21,564 Other — 3,804 — — 3,804 Net cash used for investing activities (7,607 ) (387,821 ) (24,271 ) — (419,699 ) Cash flow from financing activities: Proceeds from investment by member (146,533 ) 162,148 — — 15,615 Net proceeds from debt issuance 64,500 — — — 64,500 Loans received from and payments made on loans from other Summit Companies 51,696 (65,845 ) 6,647 7,502 — Payments on long-term debt (69,265 ) (15,662 ) (115 ) — (85,042 ) Payments on acquisition-related liabilities — (34,004 ) — — (34,004 ) Financing costs (550 ) — — — (550 ) Distributions from partnership (2,569 ) — — — (2,569 ) Other (879 ) (1,031 ) (33 ) — (1,943 ) Net cash (used in) provided by financing activities (103,600 ) 45,606 6,499 7,502 (43,993 ) Impact of cash on foreign currency — — (724 ) — (724 ) Net decrease in cash (253,522 ) (1,814 ) (7,214 ) 7,502 (255,048 ) Cash — Beginning of period 370,741 10,254 14,933 (12,372 ) 383,556 Cash — End of period $ 117,219 $ 8,440 $ 7,719 $ (4,870 ) $ 128,508 Condensed Consolidating Statements of Cash Flows For the year ended December 30, 2017 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Net cash (used in) provided by operating activities $ (127,102 ) $ 392,316 $ 29,918 $ — $ 295,132 Cash flow from investing activities: Acquisitions, net of cash acquired (24,538 ) (324,892 ) (25,500 ) — (374,930 ) Purchase of property, plant and equipment (6,196 ) (182,295 ) (5,655 ) — (194,146 ) Proceeds from the sale of property, plant, and equipment — 16,822 250 — 17,072 Other — (471 ) — — (471 ) Net cash used for investing activities (30,734 ) (490,836 ) (30,905 ) — (552,475 ) Cash flow from financing activities: Proceeds from investment by member 40,913 252,911 10,717 — 304,541 Capital issuance costs (627 ) — — — (627 ) Net proceeds from debt issuance 302,000 — — — 302,000 Loans received from and payments made on loans from other Summit Companies 119,858 (108,026 ) (10,126 ) (1,706 ) — Payments on long-term debt (8,463 ) (7,967 ) (8 ) — (16,438 ) Purchase of noncontrolling interests — (532 ) — — (532 ) Payments on acquisition-related liabilities — (32,150 ) — — (32,150 ) Financing costs (6,416 ) — — — (6,416 ) Distributions from partnership (51,986 ) — — — (51,986 ) Other (564 ) (282 ) (20 ) — (866 ) Net cash provided by financing activities 394,715 103,954 563 (1,706 ) 497,526 Impact of cash on foreign currency — — 701 — 701 Net (decrease) increase in cash 236,879 5,434 277 (1,706 ) 240,884 Cash — Beginning of period 133,862 4,820 14,656 (10,666 ) 142,672 Cash — End of period $ 370,741 $ 10,254 $ 14,933 $ (12,372 ) $ 383,556

Supplementary Data (Unaudited)

Supplementary Data (Unaudited)	12 Months Ended
	Dec. 28, 2019
Quarterly Financial Information [Line Items]
Supplementary Data (Unaudited)	Supplementary Data (Unaudited) Supplemental financial information (unaudited) by quarter is shown below for the years ended December 28, 2019 and December 29, 2018 . 2019 2018 4Q 3Q 2Q 1Q 4Q 3Q 2Q 1Q Net revenue $ 506,259 $ 665,847 $ 552,591 $ 305,950 $ 445,090 $ 625,017 $ 549,235 $ 289,916 Operating income (loss) 59,926 130,881 80,422 (57,671 ) 28,545 108,167 77,279 (51,525 ) Net income (loss) 36,397 58,237 37,990 (71,501 ) (18,627 ) 73,992 36,913 (55,948 ) Net income (loss) attributable to Summit Inc. 35,671 55,757 36,410 (68,772 ) (19,163 ) 71,289 35,509 (53,729 ) Basic earnings (loss) per share attributable to Summit Inc. $ 0.32 $ 0.50 $ 0.32 $ (0.62 ) $ (0.17 ) $ 0.64 $ 0.32 $ (0.49 ) Diluted earnings (loss) per share attributable to Summit Inc. 0.31 0.48 0.32 (0.62 ) (0.17 ) 0.64 0.32 (0.49 )
Summit Materials, LLC
Quarterly Financial Information [Line Items]
Supplementary Data (Unaudited)	Supplementary Data (Unaudited) Supplemental financial information (unaudited) by quarter is shown below for the years ended December 28, 2019 and December 29, 2018 : 2019 2018 4Q 3Q 2Q 1Q 4Q 3Q 2Q 1Q Net revenue $ 506,259 $ 665,847 $ 552,591 $ 305,950 $ 445,090 $ 625,017 $ 549,235 $ 289,916 Operating income (loss) 59,926 130,881 80,422 (57,671 ) 28,545 108,167 77,279 (51,525 ) Net income (loss) 41,461 85,199 53,501 (91,564 ) (4,596 ) 90,427 46,602 (68,596 )

Summary of Organization and S_2

Summary of Organization and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 28, 2019
Company Information
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. As a result of the Reorganization, Summit Holdings became a variable interest entity over which Summit Inc. has 100% voting power and control and for which Summit Inc. has the obligation to absorb losses and the right to receive benefits. The Company’s fiscal year is based on a 52-53 week year with each quarter composed of 13 weeks ending on a Saturday. The 53-week year last occurred in 2015, and will occur in 2020. For a summary of the changes in Summit Inc.’s ownership of Summit Holdings, see Note 11, Stockholders’ Equity. The Company attributes consolidated stockholders’ equity and net income separately to the controlling and noncontrolling interests. The Company accounts for investments in entities for which it has an ownership of 20%
Use of Estimates	Use of Estimates
Business and Credit Concentrations	Business and Credit Concentrations— The Company’s operations are conducted primarily across 23
Accounts Receivable	Accounts Receivable —Accounts receivable are stated at the amount management expects to collect from outstanding balances. Management provides for probable uncollectible amounts through a charge to earnings and a credit to a valuation allowance based on its assessment of the collectability of individual accounts. In establishing the allowance, management considers historical losses adjusted to take into account current market conditions and its customers’ financial condition, the amount of receivables in dispute, the current receivables aging and current payment terms. Balances that remain outstanding after reasonable collection efforts are exercised are written off through a charge to the valuation allowance. The balances billed but not paid by customers, pursuant to retainage provisions included in contracts, are generally due upon completion of the contracts.
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 plastics components, and from the provision of services, which are primarily paving and related services, but also include landfill operations, the receipt and disposal of waste that is converted to fuel for use in our cement plants. Products We earn revenue from the sale of products, which primarily include aggregates, cement, ready-mix concrete and asphalt, but also include concrete products, net of discounts or allowances, if any, and freight and delivery charges billed to customers. Freight and delivery charges associated with cement sales are recorded on a net basis together with freight costs within cost of sales. Revenue for product sales is recognized when evidence of an arrangement exists and when control passes, which generally is when the product is shipped. Aggregates and cement products are sold point-of-sale through purchase orders. When the product is sold on account, collectability typically occurs 30 to 60 days after the sale. Revenue is recognized when cash is received from the customer at the point of sale or when the products are delivered or collected on site. There are no other timing implications that will create a contract asset or liability, and contract modifications are unlikely given the timing and nature of the transaction. Material sales are likely to have multiple performance obligations if the product is sold with delivery. In these instances, delivery most often occurs on the same day as the control of the product transfers to the customer. As a result, even in the case of multiple performance obligations, the performance obligations are satisfied concurrently and revenue is recognized simultaneously. Services We earn revenue from the provision of services, which are primarily paving and related services, but also include landfill operations and the receipt and disposal of waste that is converted to fuel for use in our cement plants. Revenue from the receipt of waste fuels is recognized when the waste is accepted and a corresponding liability is recognized for the costs to process the waste into fuel for the manufacturing of cement or to ship the waste offsite for disposal in accordance with applicable regulations. Collectability of service contracts is due reasonably after certain milestones in the contract are performed. Milestones vary by project, but are typically calculated using monthly progress based on the percentage of completion or a customer’s engineer review of progress. The majority of the time, collection occurs within 90 days of billing and cash is received within the same fiscal year as services performed. On most projects, the customer will withhold a portion of the invoice for retainage, which may last longer than a year depending on the job. Revenue derived from paving and related services is recognized using the percentage of completion method, which approximates progress towards completion. Under the percentage of completion method, we recognize paving and related services revenue as services are rendered. 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, and therefore revenue, are opened and completed within one year, with the most activity during the spring, summer and fall. We estimate profit as the difference between total estimated revenue and total estimated cost of a contract and recognize that profit over the life of the contract based on input measures. 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. We include revisions of estimated profits on contracts in earnings under the cumulative catch-up method, under which the effect of revisions in estimates is recognized immediately. If a revised estimate of contract profitability reveals an anticipated loss on the contract, we recognize the loss in the period it is identified. 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. Contract estimates involve various assumptions and projections relative to the outcome of future events over multiple periods, including future labor productivity and availability, the nature and complexity of the work to be performed, the cost and availability of materials, the effect of delayed performance, and the availability and timing of funding from the customer. These estimates are based on our best judgment. A significant change in one or more of these estimates could affect the profitability of one or more of our contracts. We review our contract estimates regularly to assess revisions in contract values and estimated costs at completion. Inherent uncertainties in estimating costs make it at least reasonably possible that the estimates used will change within the near term and over the life of the contracts. No material adjustments to a contract were recognized in the year ended December 28, 2019 . We recognize claims when the amount of the claim can be estimated reliably and its realization is probable. In evaluating these criteria, we consider the contractual basis for the claim, the cause of any additional costs incurred, the reasonableness of those costs and the objective evidence available to support the claim. When the contract includes variable consideration, we estimate the amount of consideration to which we will be entitled in exchange for transferring the promised goods or services to a customer. The amount of estimated variable consideration included in the transaction price is the amount for which it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. Types of variable consideration include, but are not limited to, liquidated damages and other performance penalties and production and placement bonuses. The majority of contract modifications relate to the original contract and are often an extension of the original performance obligation. Predominately, modifications are not distinct from the terms in the original contract; therefore, they are considered part of a single performance obligation. We account for the modification using a cumulative catch-up adjustment. However, there are instances where goods or services in a modification are distinct from those transferred prior to the modification. In these situations, we account for the modifications as either a separate contract or prospectively depending on the facts and circumstances of the modification. Generally, construction contracts contain mobilization costs which are categorized as costs to fulfill a contract. These costs are excluded from any measure of progress toward contract fulfillment. These costs do not result in the transfer of control of a good or service to the customer and are amortized over the life of the contract. Costs and estimated earnings in excess of billings are composed principally of revenue recognized on contracts on the percentage of completion method for which billings had not been presented to customers because the amounts were not billable under the contract terms at the balance sheet date. In accordance with the contract terms, the unbilled receivables at the balance sheet date are expected to be billed in following periods. Billings in excess of costs and estimated earnings represent billings in excess of revenue recognized. Contract assets and liabilities are netted on a contract-by-contract basis.
Inventories	Inventories —Inventories consist of stone that has been removed from quarries and processed for future sale, cement, raw materials and finished concrete blocks. Inventories are valued at the lower of cost or market and are accounted for on a first-in first-out basis or an average cost basis. If items become obsolete or otherwise unusable or if quantities exceed what is projected to be sold within a reasonable period of time, they will be charged to costs of production in the period that the items are designated as obsolete or excess inventory. Stripping costs are costs of removing overburden and waste material to access aggregate materials and are expensed as incurred.
Property, Plant and Equipment, net	Property, Plant and Equipment, net —Property, plant and equipment are recorded at cost, less accumulated depreciation, depletion and amortization. Expenditures for additions and improvements that significantly add to the productive capacity or extend the useful life of an asset are capitalized. Repair and maintenance costs that do not substantially expand productive capacity or extend the life of property, plant and equipment are expensed as incurred. Landfill airspace is included in property, plant and equipment at cost and is amortized based on the portion of the airspace used during the period compared to the gross estimated value of available airspace, which is updated periodically as circumstances dictate. Management reassesses the landfill airspace capacity with any changes in value recorded in cost of revenue. Capitalized landfill costs include expenditures for the acquisition of land and related airspace, engineering and permitting costs, cell construction costs and direct site improvement costs. Upon disposal of an asset, the cost and related accumulated depreciation are removed from the Company’s accounts and any gain or loss is included in general and administrative expenses. The Company reviews the carrying value of property, plant and equipment for impairment whenever events or circumstances indicate that the carrying value of an asset may not be recoverable from the estimated future cash flows expected to result from its use and eventual disposition. Such indicators may include, among others, deterioration in general economic conditions, adverse changes in the markets in which an entity operates, increases in input costs that have a negative effect on earnings and cash flows or a trend of negative or declining cash flows over multiple periods. Property, plant and equipment is tested for impairment at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets. As a result, the property, plant and equipment impairment test is at a significantly lower level than the level at which goodwill is tested for impairment. In markets where the Company does not produce downstream products, such as ready-mix concrete, asphalt paving mix and paving and related services, the lowest level of largely independent identifiable cash flows is at the individual aggregates operation or a group of aggregates operations collectively serving a local market or the cement operations. Conversely, in vertically-integrated markets, the cash flows of the downstream and upstream businesses are not largely independently identifiable and the vertically-integrated operations are considered the lowest level of largely independent identifiable cash flows.
Accrued Mining and Landfill Reclamation	Accrued Mining and Landfill Reclamation —The mining reclamation reserve and financial commitments for landfill closure and post-closure activities are based on management’s estimate of future cost requirements to reclaim property at both currently operating and closed sites. Estimates of these obligations have been developed based on management’s interpretation of current requirements and proposed regulatory changes and are intended to approximate fair value. Costs are estimated in current dollars, inflated until the expected time of payment, and then discounted back to present value using a credit-adjusted, risk-free rate on obligations of similar maturity, adjusted to reflect the Company’s credit rating. Changes in the credit-adjusted, risk-free rate do not change recorded liabilities. However, subsequent increases in the recognized obligations are measured using a current credit-adjusted, risk-free rate. Decreases in the recognized obligations are measured at the initial credit-adjusted, risk-free rate. Significant changes in inflation rates or the amount or timing of future cost estimates typically result in both (1) a current adjustment to the recorded liability (and corresponding adjustment to the asset) and (2) a change in accretion of the liability and depreciation of the asset to be recorded prospectively over the remaining capacity of the unmined quarry or landfill.
Goodwill	Goodwill —Goodwill represents the purchase price paid in excess of the fair value of net tangible and intangible assets acquired. Goodwill recorded in connection with the Company’s acquisitions is primarily attributable to the expected profitability, assembled workforces of the acquired businesses and the synergies expected to arise after the Company’s acquisition of those businesses. Goodwill is not amortized, but is tested annually for impairment as of the first day of the fourth quarter and at any time that events or circumstances indicate that goodwill may be impaired. A qualitative approach may first be applied to determine whether it is more likely than not that the estimated fair value of a reporting unit is less than its carrying amount. If, as a result of the qualitative assessment, it is determined that an impairment is more likely than not, the two-step quantitative impairment test is then performed, otherwise further analysis is not required. The two-step impairment test first identifies potential goodwill impairment for each reporting unit and then, if necessary, measures the amount of the impairment loss.
Income Taxes	Income Taxes —Summit Inc. is a corporation subject to income taxes in the United States. Certain subsidiaries, including Summit Holdings, or subsidiary groups of the Company are taxable separate from Summit Inc. The provision for income taxes, or Summit Inc.’s proportional share of the provision, are included in the Company’s consolidated financial statements. The Company’s deferred income tax assets and liabilities are computed for differences between the tax basis and financial statement amounts that will result in taxable or deductible amounts in the future. The computed deferred balances are based on enacted tax laws and applicable rates for the periods in which the differences are expected to affect taxable income. A valuation allowance is recognized for deferred tax assets if it is more likely than not that some portion or all of the net deferred tax assets will not be realized. In making such a determination, all available positive and negative evidence is considered, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If the Company determines it would be able to realize its deferred tax assets for which a valuation allowance had been recorded then an adjustment would be made to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company evaluates the tax positions taken on income tax returns that remain open and positions expected to be taken on the current year tax returns to identify uncertain tax positions. Unrecognized tax benefits on uncertain tax positions are recorded on the basis of a two-step process in which (1) the Company determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, the largest amount of tax benefit that is more than 50 percent likely to be realized is recognized. Interest and penalties related to unrecognized tax benefits are recorded in income tax expense (benefit).
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 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. As noted above, 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. 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.
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.
New Accounting Standards	New Accounting Standards — In February 2016, the Financial Accounting Standards Board FASB ("FASB") issued Accounting Standards Update ("ASU") No. 2016-02, Leases (Topic 842), which requires lessees to recognize most leases on the balance sheet. Lessees are required to disclose more quantitative and qualitative information about the leases than current U.S. GAAP requires. The ASU and subsequent amendments issued in 2018 are effective for public entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. We adopted the standard effective December 30, 2018 using the modified retrospective approach. The modified retrospective approach provides a method for recording existing leases at adoption. In addition, we elected the package of practical expedients permitted under the transition guidance within the new standard, which among other things, allowed us to carry forward the historical lease classification. In addition, we elected the hindsight practical expedient to determine the lease term for existing leases. The most significant impact upon adoption was the recognition of $36.8 million of operating lease right-of-use assets and $36.8 million operating lease liabilities. The standard had no material impact on our statements of operations and cash flows. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities, allowing more financial and nonfinancial hedging strategies to be eligible for hedge accounting. The ASU is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. The adoption of this new ASU did not have a material impact on our consolidated financial results. In June 2018, the FASB issued ASU No. 2018-07, Compensation—Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting, increasing the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. The ASU is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. The adoption of this new ASU did not have a material impact on our consolidated financial results.
Summit Materials, LLC
Company Information
Principles of Consolidation	Principles of Consolidation –The consolidated financial statements include the accounts of Summit LLC and its majority owned subsidiaries. All intercompany balances and transactions have been eliminated. The Company attributes consolidated member’s interest and net income separately to the controlling and noncontrolling interests. Noncontrolling interests in consolidated subsidiaries represent a 20% ownership in Ohio Valley Asphalt, LLC and, prior to the initial public offering (“IPO”) and concurrent purchase of the noncontrolling interests Continental Cement Company, L.L.C. (“Continental Cement”), a 30% redeemable ownership in Continental Cement. The Company accounts for investments in entities for which it has an ownership of 20% to 50% using the equity method of accounting. In the fourth quarter of 2017, we purchased the remaining noncontrolling interest in Ohio Valley Asphalt, LLC.
Use of Estimates	Use of Estimates — Preparation of these consolidated financial statements in conformity with U.S. generally accepted accounting principles (“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, Utah, Kansas 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
Accounts Receivable	Accounts Receivable —Accounts receivable are stated at the amount management expects to collect from outstanding balances. Management provides for probable uncollectible amounts through a charge to earnings and a credit to a valuation allowance based on its assessment of the collectability of individual accounts. In establishing the allowance, management considers historical losses adjusted to take into account current market conditions and its customers’ financial condition, the amount of receivables in dispute, the current receivables aging and current payment terms. Balances that remain outstanding after reasonable collection efforts are exercised are written off through a charge to the valuation allowance. The balances billed but not paid by customers, pursuant to retainage provisions included in contracts, are generally due upon completion of the contracts.
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 plastics components, and from the provision of services, which are primarily paving and related services, but also include landfill operations, the receipt and disposal of waste that is converted to fuel for use in our cement plants. Products We earn revenue from the sale of products, which primarily include aggregates, cement, ready-mix concrete and asphalt, but also include concrete products, net of discounts or allowances, if any, and freight and delivery charges billed to customers. Freight and delivery charges associated with cement sales are recorded on a net basis together with freight costs within cost of sales. Revenue for product sales is recognized when evidence of an arrangement exists and when control passes, which generally is when the product is shipped. Aggregates and cement products are sold point-of-sale through purchase orders. When the product is sold on account, collectability typically occurs 30 to 60 days after the sale. Revenue is recognized when cash is received from the customer at the point of sale or when the products are delivered or collected on site. There are no other timing implications that will create a contract asset or liability, and contract modifications are unlikely given the timing and nature of the transaction. Material sales are likely to have multiple performance obligations if the product is sold with delivery. In these instances, delivery most often occurs on the same day as the control of the product transfers to the customer. As a result, even in the case of multiple performance obligations, the performance obligations are satisfied concurrently and revenue is recognized simultaneously. Services We earn revenue from the provision of services, which are primarily paving and related services, but also include landfill operations and the receipt and disposal of waste that is converted to fuel for use in our cement plants. Revenue from the receipt of waste fuels is recognized when the waste is accepted and a corresponding liability is recognized for the costs to process the waste into fuel for the manufacturing of cement or to ship the waste offsite for disposal in accordance with applicable regulations. Collectability of service contracts is due reasonably after certain milestones in the contract are performed. Milestones vary by project, but are typically calculated using monthly progress based on the percentage of completion or a customer’s engineer review of progress. The majority of the time, collection occurs within 90 days of billing and cash is received within the same fiscal year as services performed. On most projects, the customer will withhold a portion of the invoice for retainage, which may last longer than a year depending on the job. Revenue derived from paving and related services is recognized using the percentage of completion method, which approximates progress towards completion. Under the percentage of completion method, we recognize paving and related services revenue as services are rendered. 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, and therefore revenue, are opened and completed within one year, with the most activity during the spring, summer and fall. We estimate profit as the difference between total estimated revenue and total estimated cost of a contract and recognize that profit over the life of the contract based on input measures. 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. We include revisions of estimated profits on contracts in earnings under the cumulative catch-up method, under which the effect of revisions in estimates is recognized immediately. If a revised estimate of contract profitability reveals an anticipated loss on the contract, we recognize the loss in the period it is identified. 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. Contract estimates involve various assumptions and projections relative to the outcome of future events over multiple periods, including future labor productivity and availability, the nature and complexity of the work to be performed, the cost and availability of materials, the effect of delayed performance, and the availability and timing of funding from the customer. These estimates are based on our best judgment. A significant change in one or more of these estimates could affect the profitability of one or more of our contracts. We review our contract estimates regularly to assess revisions in contract values and estimated costs at completion. Inherent uncertainties in estimating costs make it at least reasonably possible that the estimates used will change within the near term and over the life of the contracts. No material adjustments to a contract were recognized in the year ended December 28, 2019 . We recognize claims when the amount of the claim can be estimated reliably and its realization is probable. In evaluating these criteria, we consider the contractual basis for the claim, the cause of any additional costs incurred, the reasonableness of those costs and the objective evidence available to support the claim. When the contract includes variable consideration, we estimate the amount of consideration to which we will be entitled in exchange for transferring the promised goods or services to a customer. The amount of estimated variable consideration included in the transaction price is the amount for which it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. Types of variable consideration include, but are not limited to, liquidated damages and other performance penalties and production and placement bonuses. The majority of contract modifications relate to the original contract and are often an extension of the original performance obligation. Predominately, modifications are not distinct from the terms in the original contract; therefore, they are considered part of a single performance obligation. We account for the modification using a cumulative catch-up adjustment. However, there are instances where goods or services in a modification are distinct from those transferred prior to the modification. In these situations, we account for the modifications as either a separate contract or prospectively depending on the facts and circumstances of the modification. Generally, construction contracts contain mobilization costs which are categorized as costs to fulfill a contract. These costs are excluded from any measure of progress toward contract fulfillment. These costs do not result in the transfer of control of a good or service to the customer and are amortized over the life of the contract. Costs and estimated earnings in excess of billings are composed principally of revenue recognized on contracts on the percentage of completion method for which billings had not been presented to customers because the amounts were not billable under the contract terms at the balance sheet date. In accordance with the contract terms, the unbilled receivables at the balance sheet date are expected to be billed in following periods. Billings in excess of costs and estimated earnings represent billings in excess of revenue recognized. Contract assets and liabilities are netted on a contract-by-contract basis.
Inventories	Inventories —Inventories consist of stone that has been removed from quarries and processed for future sale, cement, raw materials and finished concrete blocks. Inventories are valued at the lower of cost or market and are accounted for on a first-in first-out basis or an average cost basis. If items become obsolete or otherwise unusable or if quantities exceed what is projected to be sold within a reasonable period of time, they will be charged to costs of production in the period that the items are designated as obsolete or excess inventory. Stripping costs are costs of removing overburden and waste material to access aggregate materials and are expensed as incurred.
Property, Plant and Equipment, net	Property, Plant and Equipment, net —Property, plant and equipment are recorded at cost, less accumulated depreciation, depletion and amortization. Expenditures for additions and improvements that significantly add to the productive capacity or extend the useful life of an asset are capitalized. Repair and maintenance costs that do not substantially expand productive capacity or extend the life of property, plant and equipment are expensed as incurred. Landfill airspace is included in property, plant and equipment at cost and is amortized based on the portion of the airspace used during the period compared to the gross estimated value of available airspace, which is updated periodically as circumstances dictate. Management reassesses the landfill airspace capacity with any changes in value recorded in cost of revenue. Capitalized landfill costs include expenditures for the acquisition of land and related airspace, engineering and permitting costs, cell construction costs and direct site improvement costs. Upon disposal of an asset, the cost and related accumulated depreciation are removed from the Company’s accounts and any gain or loss is included in general and administrative expenses. The Company reviews the carrying value of property, plant and equipment for impairment whenever events or circumstances indicate that the carrying value of an asset may not be recoverable from the estimated future cash flows expected to result from its use and eventual disposition. Such indicators may include, among others, deterioration in general economic conditions, adverse changes in the markets in which an entity operates, increases in input costs that have a negative effect on earnings and cash flows or a trend of negative or declining cash flows over multiple periods. Property, plant and equipment is tested for impairment at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets. As a result, the property, plant and equipment impairment test is at a significantly lower level than the level at which goodwill is tested for impairment. In markets where the Company does not produce downstream products, such as ready-mix concrete, asphalt paving mix and paving and related services, the lowest level of largely independent identifiable cash flows is at the individual aggregates operation or a group of aggregates operations collectively serving a local market or the cement operations. Conversely, in vertically-integrated markets, the cash flows of the downstream and upstream businesses are not largely independently identifiable and the vertically-integrated operations are considered the lowest level of largely independent identifiable cash flows.
Accrued Mining and Landfill Reclamation	Accrued Mining and Landfill Reclamation —The mining reclamation reserve and financial commitments for landfill closure and post-closure activities are based on management’s estimate of future cost requirements to reclaim property at both currently operating and closed sites. Estimates of these obligations have been developed based on management’s interpretation of current requirements and proposed regulatory changes and are intended to approximate fair value. Costs are estimated in current dollars, inflated until the expected time of payment, and then discounted back to present value using a credit-adjusted, risk-free rate on obligations of similar maturity, adjusted to reflect the Company’s credit rating. Changes in the credit-adjusted, risk-free rate do not change recorded liabilities. However, subsequent increases in the recognized obligations are measured using a current credit-adjusted, risk-free rate. Decreases in the recognized obligations are measured at the initial credit-adjusted, risk-free rate. Significant changes in inflation rates or the amount or timing of future cost estimates typically result in both (1) a current adjustment to the recorded liability (and corresponding adjustment to the asset) and (2) a change in accretion of the liability and depreciation of the asset to be recorded prospectively over the remaining capacity of the unmined quarry or landfill.
Goodwill	Goodwill —Goodwill represents the purchase price paid in excess of the fair value of net tangible and intangible assets acquired. Goodwill recorded in connection with the Company’s acquisitions is primarily attributable to the expected profitability, assembled workforces of the acquired businesses and the synergies expected to arise after the Company’s acquisition of those businesses. Goodwill is not amortized, but is tested annually for impairment as of the first day of the fourth quarter and at any time that events or circumstances indicate that goodwill may be impaired. A qualitative approach may first be applied to determine whether it is more likely than not that the estimated fair value of a reporting unit is less than its carrying amount. If, as a result of the qualitative assessment, it is determined that an impairment is more likely than not, the two-step quantitative impairment test is then performed, otherwise further analysis is not required. The two-step impairment test first identifies potential goodwill impairment for each reporting unit and then, if necessary, measures the amount of the impairment loss.
Income Taxes	Income Taxes —As a limited liability company, the Company’s federal and state income tax attributes are generally passed to its member. However, certain subsidiaries, or subsidiary groups, of the Company are taxable entities subject to income taxes in the United States and Canada, the provisions for which are included in the consolidated financial statements. Significant judgments and estimates are required in the determination of the consolidated income tax expense. The Company’s deferred income tax assets and liabilities are computed for differences between the tax basis and financial statement amounts that will result in taxable or deductible amounts in the future. The computed deferred balances are based on enacted tax laws and applicable rates for the periods in which the differences are expected to affect taxable income. A valuation allowance is recognized for deferred tax assets if it is more likely than not that some portion or all of the net deferred tax assets will not be realized. In making such a determination, all available positive and negative evidence is considered, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If the Company determines it would be able to realize its deferred tax assets for which a valuation allowance had been recorded then an adjustment would be made to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company evaluates the tax positions taken on income tax returns that remain open and positions expected to be taken on the current year tax returns to identify uncertain tax positions. Unrecognized tax benefits on uncertain tax positions are recorded on the basis of a two-step process in which (1) the Company determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, the largest amount of tax benefit that is more than 50 percent likely to be realized is recognized. Interest and penalties related to unrecognized tax benefits are recorded in income tax benefit.
New Accounting Standards	New Accounting Standards — In February 2016, the Financial Accounting Standards Board FASB ("FASB") issued Accounting Standards Update ("ASU") No. 2016-02, Leases (Topic 842), which requires lessees to recognize most leases on the balance sheet. Lessees are required to disclose more quantitative and qualitative information about the leases than current U.S. GAAP requires. The ASU and subsequent amendments issued in 2018 are effective for public entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. We adopted the standard effective December 30, 2018 using the modified retrospective approach. The modified retrospective approach provides a method for recording existing leases at adoption. In addition, we elected the package of practical expedients permitted under the transition guidance within the new standard, which among other things, allowed us to carry forward the historical lease classification. In addition, we elected the hindsight practical expedient to determine the lease term for existing leases. The most significant impact upon adoption was the recognition of $36.8 million of operating lease right-of-use assets and $36.8 million operating lease liabilities. The standard had no material impact on our statements of operations and cash flows. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities, allowing more financial and nonfinancial hedging strategies to be eligible for hedge accounting. The ASU is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. The adoption of this new ASU did not have a material impact on our consolidated financial results. In June 2018, the FASB issued ASU No. 2018-07, Compensation — Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting, increasing the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. The ASU is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. The adoption of this new ASU did not have a material impact on our consolidated financial results.

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 28, 2019
Summary of Acquisitions by Region	The following table summarizes the Company’s acquisitions by region and year: 2019 2018 2017 West 2 5 6 East (1) — 7 8 ______________________ (1) In addition, the Company acquired certain assets of a small ready-mix concrete operation in the second quarter of 2018.
Summary of Assets Acquired and Liabilities Assumed	The table below summarizes aggregated information regarding the fair values of the assets acquired and liabilities assumed as of the respective acquisition dates. 2019 2018 Financial assets $ — $ 14,769 Inventories 52 18,313 Property, plant and equipment 3,542 124,957 Intangible assets — 3,175 Other assets — 1,539 Financial liabilities (36 ) (13,529 ) Other long-term liabilities — (8,125 ) Net assets acquired 3,558 141,099 Goodwill 1,834 154,120 Purchase price 5,392 295,219 Acquisition-related liabilities — (49,202 ) Net cash paid for acquisitions $ 5,392 $ 246,017
Schedule of remaining payments under noncompete and deferred consideration agreements	The remaining payments due under these noncompete and deferred consideration agreements are as follows: 2020 $ 31,708 2021 9,705 2022 3,411 2023 2,657 2024 2,620 Thereafter 7,020 Total scheduled payments 57,121 Present value adjustments (7,889 ) Total noncompete obligations and deferred consideration $ 49,232
Summit Materials, LLC
Summary of Acquisitions by Region	The following table summarizes the Company’s acquisitions by region and year: 2019 2018 2017 West 2 5 6 East (1) — 7 8 ______________________ (1) In addition, the Company acquired certain assets of a small ready-mix concrete operation in the second quarter of 2018.
Summary of Assets Acquired and Liabilities Assumed	The table below summarizes aggregated information regarding the fair values of the assets acquired and liabilities assumed as of the respective acquisition dates. 2019 2018 Financial assets $ — $ 14,769 Inventories 52 18,313 Property, plant and equipment 3,542 124,957 Intangible assets — 3,175 Other assets — 1,539 Financial liabilities (36 ) (13,529 ) Other long-term liabilities — (8,125 ) Net assets acquired 3,558 141,099 Goodwill 1,834 154,120 Purchase price 5,392 295,219 Acquisition-related liabilities — (49,202 ) Net cash paid for acquisitions $ 5,392 $ 246,017
Schedule of remaining payments under noncompete and deferred consideration agreements	The remaining payments due under these noncompete and deferred consideration agreements are as follows: 2020 $ 29,208 2021 7,205 2022 3,411 2023 2,657 2024 2,620 Thereafter 7,020 Total scheduled payments 52,121 Present value adjustments (7,524 ) Total noncompete obligations and deferred consideration $ 44,597

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Dec. 28, 2019
Goodwill by Reportable Segment and in Total	The following table presents goodwill by reportable segments and in total: West East Cement Total Balance—December 30, 2017 $ 526,290 $ 305,374 $ 204,656 $ 1,036,320 Acquisitions 59,148 101,431 — 160,579 Foreign currency translation adjustments (4,871 ) — — (4,871 ) Balance, December 29, 2018 $ 580,567 $ 406,805 $ 204,656 $ 1,192,028 Acquisitions (1) 1,657 3,621 — 5,278 Foreign currency translation adjustments 2,393 — — 2,393 Balance, December 28, 2019 $ 584,617 $ 410,426 $ 204,656 $ 1,199,699 ______________________ (1) Reflects goodwill from 2019 acquisitions and working capital adjustments from prior year acquisitions.
Summit Materials, LLC
Goodwill by Reportable Segment and in Total	The following table presents goodwill by reportable segments and in total: West East Cement Total Balance—December 30, 2017 $ 527,290 $ 305,374 $ 204,656 $ 1,037,320 Acquisitions 59,148 101,431 — 160,579 Foreign currency translation adjustments (4,871 ) — — (4,871 ) Balance, December 29, 2018 $ 581,567 $ 406,805 $ 204,656 $ 1,193,028 Acquisitions (1) 1,657 3,621 — 5,278 Foreign currency translation adjustments 2,393 — — 2,393 Balance, December 28, 2019 $ 585,617 $ 410,426 $ 204,656 $ 1,200,699 ______________________ (1) Reflects goodwill from 2019 acquisitions and working capital adjustments from prior year acquisitions.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 28, 2019
Revenue from External Customer [Line Items]
Summary of Revenue by Products	Revenue by product for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 consisted of the following: 2019 2018 2017 Revenue by product*: Aggregates $ 469,670 $ 373,824 $ 313,383 Cement 266,235 258,876 282,041 Ready-mix concrete 607,622 584,114 492,302 Asphalt 330,750 301,247 285,653 Paving and related services 360,234 379,540 371,763 Other 187,629 203,401 187,433 Total revenue $ 2,222,140 $ 2,101,002 $ 1,932,575 ______________________ * Revenue from the liquid asphalt terminals is included in asphalt revenue.
Summary of Contract Assets and Liabilities	The following table outlines the significant changes in contract assets and contract liability balances from December 29, 2018 to December 28, 2019 . Also included in the table is the net change in the estimate as a percentage of aggregate revenue for such contracts: Costs and estimated Billings in excess earnings in of costs and excess of billings estimated earnings Balance—December 29, 2018 $ 18,602 $ 11,840 Changes in revenue billed, contract price or cost estimates (5,558 ) 1,988 Other 44 36 Balance—December 28, 2019 $ 13,088 $ 13,864
Summary of Accounts Receivable, Net	Accounts receivable, net consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Trade accounts receivable $ 191,672 $ 157,601 Construction contract receivables 47,966 47,994 Retention receivables 17,808 15,010 Receivables from related parties 1,596 629 Accounts receivable 259,042 221,234 Less: Allowance for doubtful accounts (5,786 ) (6,716 ) Accounts receivable, net $ 253,256 $ 214,518
Summit Materials, LLC
Revenue from External Customer [Line Items]
Summary of Revenue by Products	Revenue by product for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 consisted of the following: 2019 2018 2017 Revenue by product*: Aggregates $ 469,670 $ 373,824 $ 313,383 Cement 266,235 258,876 282,041 Ready-mix concrete 607,622 584,114 492,302 Asphalt 330,750 301,247 285,653 Paving and related services 360,234 379,540 371,763 Other 187,629 203,401 187,433 Total revenue $ 2,222,140 $ 2,101,002 $ 1,932,575 ______________________ *Revenue from the liquid asphalt terminals is included in asphalt revenue.
Summary of Contract Assets and Liabilities	The following table outlines the significant changes in contract assets and contract liability balances from December 29, 2018 to December 28, 2019 . Also included in the table is the net change in the estimate as a percentage of aggregate revenue for such contracts: Costs and estimated Billings in excess earnings in of costs and excess of billings estimated earnings Balance—December 29, 2018 $ 18,602 $ 11,840 Changes in revenue billed, contract price or cost estimates (5,558 ) 1,988 Other 44 36 Balance—December 28, 2019 $ 13,088 $ 13,864
Summary of Accounts Receivable, Net	Accounts receivable, net consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Trade accounts receivable $ 191,672 $ 157,601 Construction contract receivables 47,966 47,994 Retention receivables 17,808 15,010 Receivables from related parties 1,596 629 Accounts receivable 259,042 221,234 Less: Allowance for doubtful accounts (5,786 ) (6,716 ) Accounts receivable, net $ 253,256 $ 214,518

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 28, 2019
Inventory [Line Items]
Components of Inventories	Inventories consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Aggregate stockpiles $ 140,461 $ 151,300 Finished goods 33,023 34,993 Work in process 7,664 7,478 Raw materials 23,639 20,080 Total $ 204,787 $ 213,851
Summit Materials, LLC
Inventory [Line Items]
Components of Inventories	Inventories consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Aggregate stockpiles $ 140,461 $ 151,300 Finished goods 33,023 34,993 Work in process 7,664 7,478 Raw materials 23,639 20,080 Total $ 204,787 $ 213,851

Property, Plant and Equipment_2

Property, Plant and Equipment, net and Intangibles, net (Tables)	12 Months Ended
	Dec. 28, 2019
Property, Plant and Equipment [Line Items]
Summary of Property, Plant and Equipment	The estimated useful lives are generally as follows: Buildings and improvements 10 - 30 years Plant, machinery and equipment 15 - 20 years Office equipment 3 - 7 years Truck and auto fleet 5 - 8 years Mobile equipment and barges 6 - 8 years Landfill airspace and improvements 10 - 30 years Other 4 - 20 years Property, plant and equipment, net consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Land (mineral bearing) and asset retirement costs $ 333,024 $ 323,553 Land (non-mineral bearing) 182,065 184,029 Buildings and improvements 178,088 173,559 Plants, machinery and equipment 1,318,512 1,239,793 Mobile equipment and barges 501,809 468,313 Truck and auto fleet 54,838 51,938 Landfill airspace and improvements 49,766 49,754 Office equipment 43,155 39,794 Construction in progress 42,007 43,650 Property, plant and equipment 2,703,264 2,574,383 Less accumulated depreciation, depletion and amortization (955,815 ) (794,251 ) Property, plant and equipment, net $ 1,747,449 $ 1,780,132
Intangible Assets by Type and in Total	The following table shows intangible assets by type and in total: December 28, 2019 December 29, 2018 Gross Net Gross Net Carrying Accumulated Carrying Carrying Accumulated Carrying Amount Amortization Amount Amount Amortization Amount Mineral leases $ 19,064 $ (6,408 ) $ 12,656 $ 19,064 $ (5,259 ) $ 13,805 Reserve rights 6,234 (2,248 ) 3,986 6,234 (1,940 ) 4,294 Trade names 1,000 (958 ) 42 1,000 (858 ) 142 Other 7,566 (752 ) 6,814 409 (190 ) 219 Total intangible assets $ 33,864 $ (10,366 ) $ 23,498 $ 26,707 $ (8,247 ) $ 18,460
Estimated Amortization Expense for Intangible Assets	The estimated amortization expense for intangible assets for each of the next five years and thereafter is as follows: 2020 $ 2,526 2021 2,138 2022 2,142 2023 2,009 2024 1,914 Thereafter 12,769 Total $ 23,498
Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Summary of Property, Plant and Equipment	The estimated useful lives are generally as follows: Buildings and improvements 10-30 years Plant, machinery and equipment 15 - 20 years Office equipment 3-7 years Truck and auto fleet 5-8 years Mobile equipment and barges 6-8 years Landfill airspace and improvements 10-30 years Other 4-20 years Property, plant and equipment, net consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Land (mineral bearing) and asset retirement costs $ 333,024 $ 323,553 Land (non-mineral bearing) 182,065 184,029 Buildings and improvements 178,088 173,559 Plants, machinery and equipment 1,318,512 1,239,793 Mobile equipment and barges 501,809 468,313 Truck and auto fleet 54,838 51,938 Landfill airspace and improvements 49,766 49,754 Office equipment 43,155 39,794 Construction in progress 42,007 43,650 Property, plant and equipment 2,703,264 2,574,383 Less accumulated depreciation, depletion and amortization (955,815 ) (794,251 ) Property, plant and equipment, net $ 1,747,449 $ 1,780,132
Intangible Assets by Type and in Total	The following table shows intangible assets by type and in total: December 28, 2019 December 29, 2018 Gross Net Gross Net Carrying Accumulated Carrying Carrying Accumulated Carrying Amount Amortization Amount Amount Amortization Amount Mineral leases $ 19,064 $ (6,408 ) $ 12,656 $ 19,064 $ (5,259 ) $ 13,805 Reserve rights 6,234 (2,248 ) 3,986 6,234 (1,940 ) 4,294 Trade names 1,000 (958 ) 42 1,000 (858 ) 142 Other 7,566 (752 ) 6,814 409 (190 ) 219 Total intangible assets $ 33,864 $ (10,366 ) $ 23,498 $ 26,707 $ (8,247 ) $ 18,460
Estimated Amortization Expense for Intangible Assets	The estimated amortization expense for intangible assets for each of the next five years and thereafter is as follows: 2020 $ 2,526 2021 2,138 2022 2,142 2023 2,009 2024 1,914 Thereafter 12,769 Total $ 23,498

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 28, 2019
Schedule Of Accrued Expenses [Line Items]
Components of Accrued Expenses	Accrued expenses consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Interest $ 26,892 $ 26,223 Payroll and benefits 29,356 15,952 Finance lease obligations 16,007 15,557 Insurance 14,968 13,625 Non-income taxes 7,666 7,442 Professional fees 902 1,408 Other (1) 24,214 20,284 Total $ 120,005 $ 100,491 ______________________ (1) Consists primarily of subcontractor and working capital settlement accruals and deferred revenue.
Summit Materials, LLC
Schedule Of Accrued Expenses [Line Items]
Components of Accrued Expenses	Accrued expenses consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Interest $ 26,892 $ 26,223 Payroll and benefits 29,356 15,952 Finance lease obligations 16,007 15,557 Insurance 14,968 13,625 Non-income taxes 7,898 7,674 Professional fees 902 1,408 Other (1) 24,214 19,590 Total $ 120,237 $ 100,029 ______________________ (1) Consists primarily of subcontractor and working capital settlement accruals and deferred revenue.

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 28, 2019
Schedule of Debt	Debt consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Term Loan, due 2024: $624.3 million and $630.6 million, net of $1.1 million and $1.3 million discount at December 28, 2019 and December 29, 2018, respectively $ 623,140 $ 629,268 8 1/2% Senior Notes, due 2022 — 250,000 6 1/8% Senior Notes, due 2023: $650.0 million, net of $0.9 million and $1.1 million discount at December 28, 2019 and December 29, 2018, respectively 649,133 648,891 5 1/8% Senior Notes, due 2025 300,000 300,000 6 1⁄2% Senior Notes, due 2027 300,000 — Total 1,872,273 1,828,159 Current portion of long-term debt 7,942 6,354 Long-term debt $ 1,864,331 $ 1,821,805
Schedule of Contractual Payments of Long-Term Debt	The contractual payments of long-term debt, including current maturities, for the five years subsequent to December 28, 2019 , are as follows: 2020 $ 7,942 2021 6,354 2022 6,354 2023 656,354 2024 597,251 Thereafter 600,000 Total 1,874,255 Less: Original issue net discount (1,982 ) Less: Capitalized loan costs (13,274 ) Total debt $ 1,858,999
Summary of Activity for Deferred Financing Fees	The following table presents the activity for the deferred financing fees for the years ended December 28, 2019 and December 29, 2018 : Deferred financing fees Balance—December 30, 2017 $ 19,033 Loan origination fees 550 Amortization (4,108 ) Balance—December 29, 2018 $ 15,475 Loan origination fees 6,312 Amortization (3,501 ) Write off of deferred financing fees (2,850 ) Balance—December 28, 2019 $ 15,436
Summit Materials, LLC
Schedule of Debt	Debt consisted of the following as of December 28, 2019 and December 29, 2018 : 2019 2018 Term Loan, due 2024: $624.3 million and $630.6 million, net of $1.1 million and $1.3 million discount at December 28, 2019 and December 29, 2018, respectively $ 623,140 $ 629,268 8 1/2% Senior Notes, due 2022 — 250,000 6 1/8% Senior Notes, due 2023: $650.0 million, net of $0.9 million and $1.1 million discount at December 28, 2019 and December 29, 2018, respectively 649,133 648,891 5 1/8% Senior Notes, due 2025 300,000 300,000 61⁄2% Senior Notes, due 2027 300,000 — Total 1,872,273 1,828,159 Current portion of long-term debt 7,942 6,354 Long-term debt $ 1,864,331 $ 1,821,805
Schedule of Contractual Payments of Long-Term Debt	The contractual payments of long-term debt, including current maturities, for the five years subsequent to December 28, 2019 , are as follows: 2020 $ 7,942 2021 6,354 2022 6,354 2023 656,354 2024 597,251 Thereafter 600,000 Total 1,874,255 Less: Original issue net discount (1,982 ) Less: Capitalized loan costs (13,274 ) Total debt $ 1,858,999
Summary of Activity for Deferred Financing Fees	The following table presents the activity for the deferred financing fees for the years ended December 28, 2019 and December 29, 2018 : Deferred financing fees Balance—December 30, 2017 $ 19,033 Loan origination fees 550 Amortization (4,108 ) Balance—December 29, 2018 $ 15,475 Loan origination fees 6,312 Amortization (3,501 ) Write off of deferred financing fees (2,850 ) Balance—December 28, 2019 $ 15,436

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 28, 2019
Income Taxes [Line Items]
Components of Income Tax Benefit	For the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 , income taxes consisted of the following: 2019 2018 2017 Provision for income taxes: Current $ 69 $ 463 $ 2,530 Deferred 17,032 59,284 (286,507 ) Income tax expense (benefit) $ 17,101 $ 59,747 $ (283,977 )
Schedule of Reconciliation of Income Tax (Benefit) Expense	The effective tax rate on pre-tax income differs from the U.S. statutory rate of 21% , 21% , and 35% for 2019 , 2018 and 2017 , respectively, due to the following: 2019 2018 2017 Income tax expense (benefit) at federal statutory tax rate $ 16,427 $ 20,177 $ (55,365 ) Less: Income tax benefit at federal statutory tax rate for LLC entities (658 ) (561 ) (2,123 ) State and local income taxes 3,792 4,894 (5,209 ) Permanent differences (6,272 ) (5,537 ) (4,410 ) Effective tax rate change (2,006 ) 4,034 216,904 Unrecognized tax benefits 18,885 22,663 — Tax receivable agreement (benefit) expense 2,436 (8,282 ) 104,804 Change in valuation allowance (17,691 ) 17,592 (500,162 ) Impact of LP Unit ownership change — — (31,790 ) Other 2,188 4,767 (6,626 ) Income tax expense (benefit) $ 17,101 $ 59,747 $ (283,977 )
Components of Net Deferred Income Tax Liability	The following table summarizes the components of the net deferred income tax asset (liability) as December 28, 2019 and December 29, 2018 : 2019 2018 Deferred tax assets (liabilities): Net intangible assets $ 240,790 $ 275,412 Accelerated depreciation (201,126 ) (185,020 ) Net operating loss 164,335 143,234 Investment in limited partnership (31,987 ) (29,981 ) Mining reclamation reserve 2,018 1,600 Working capital (e.g., accrued compensation, prepaid assets) 37,287 36,932 Interest expense limitation carryforward 2,691 2,586 Less valuation allowance (1,675 ) (19,366 ) Deferred tax assets 212,333 225,397 Less foreign deferred tax liability (included in other noncurrent liabilities) (8,267 ) (5,133 ) Net deferred tax asset $ 204,066 $ 220,264
Schedule of Unrecognized Tax Benefits Roll Forward	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: Unrealized Tax Benefits Balance—December 30, 2017 $ — Additions based on tax position in 2018 22,663 Balance—December 29, 2018 $ 22,663 Additions based on tax position in 2019 18,885 Balance—December 28, 2019 $ 41,548
Summary of Valuation Allowance	2019 2018 Valuation Allowance: Beginning balance $ (19,366 ) $ (1,675 ) Additional basis from exchanged LP Units — (99 ) Current year decreases (increases) from operations 17,691 (17,592 ) Ending balance $ (1,675 ) $ (19,366 )
Summit Materials, LLC
Income Taxes [Line Items]
Components of Income Tax Benefit	For the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 , income taxes consisted of the following: 2019 2018 2017 Provision for income taxes: Current $ 69 $ 463 $ 2,762 Deferred 6,316 9,810 (23,107 ) Income tax expense (benefit) $ 6,385 $ 10,273 $ (20,345 )
Schedule of Reconciliation of Income Tax (Benefit) Expense	The effective tax rate on pre-tax income differs from the U.S. statutory rate of 21% , 21% and 35% for 2019, 2018 and 2017, respectively, due to the following: 2019 2018 2017 Income tax expense (benefit) at federal statutory tax rate $ 19,947 $ 15,563 $ 39,797 Less: Income tax benefit at federal statutory tax rate for LLC entities (15,387 ) (13,863 ) (36,171 ) State and local income taxes 1,680 1,614 1,751 Permanent differences 13 (1,194 ) (630 ) Effective tax rate change (725 ) (1,148 ) (24,243 ) Unrecognized tax benefits 5,038 6,487 — Valuation allowance (2,478 ) 2,586 — Other (1,703 ) 228 (849 ) Income tax benefit $ 6,385 $ 10,273 $ (20,345 )
Components of Net Deferred Income Tax Liability	The following table summarizes the components of the net deferred income tax asset (liability) as December 28, 2019 and December 29, 2018 : 2019 2018 Deferred tax (liabilities) assets: Accelerated depreciation $ (60,216 ) $ (57,437 ) Net operating loss 18,036 22,915 Investment in limited partnership (17,686 ) (16,591 ) Net intangible assets (2,554 ) (1,734 ) Mining reclamation reserve 723 570 Working capital (e.g., accrued compensation, prepaid assets) 1,366 1,059 Interest expense limitation carryforward 2,691 2,586 Net deferred tax liabilities (57,640 ) (48,632 ) Less valuation allowance (1,675 ) (4,261 ) Net deferred tax liability $ (59,315 ) $ (52,893 )
Schedule of Unrecognized Tax Benefits Roll Forward	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: Unrealized Tax Benefits Balance—December 30, 2017 $ — Additions based on tax position in 2018 6,487 Balance—December 29, 2018 $ 6,487 Additions based on tax position in 2019 5,132 Balance—December 28, 2019 $ 11,619
Summary of Valuation Allowance	2019 2018 Valuation Allowance: Beginning balance $ (4,261 ) $ (1,675 ) Current year decreases (increases) from operations 2,586 (2,586 ) Ending balance $ (1,675 ) $ (4,261 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 28, 2019
Earnings Per Share [Abstract]
Schedule of Basic Earnings Per Share	The following table shows the calculation of basic income per share: 2019 2018 2017 Net income attributable to Summit Inc. $ 59,066 $ 33,906 $ 121,830 Weighted average shares of Class A stock outstanding 112,204,067 111,380,175 108,696,438 Basic earnings per share $ 0.53 $ 0.30 $ 1.12 Diluted net income attributable to Summit Inc. $ 59,066 $ 33,906 $ 121,830 Weighted average shares of Class A stock outstanding 112,204,067 111,380,175 108,696,438 Add: stock options 87,290 282,329 308,355 Add: warrants 4,206 25,049 42,035 Add: restricted stock units 342,620 459,280 308,221 Add: performance stock units 46,535 169,813 135,849 Weighted average dilutive shares outstanding 112,684,718 112,316,646 109,490,898 Diluted earnings per share $ 0.52 $ 0.30 $ 1.11
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: 2019 2018 2017 Antidilutive shares: LP Units 3,372,706 3,512,669 4,371,705

Stockholder's Equity_Members'_2

Stockholder's Equity/Members' Interest (Tables)	12 Months Ended
	Dec. 28, 2019
Company Information
Schedule of Changes in Ownership of Summit Holdings	The following table summarizes the changes in our ownership of Summit Holdings: Summit Inc. Shares (Class A) LP Units Total Summit Inc. Ownership Percentage Balance — December 30, 2017 110,350,594 3,689,620 114,040,214 96.8 % Exchanges during period 254,102 (254,102 ) — Stock option exercises 863,898 — 863,898 Other equity transactions 190,333 — 190,333 Balance — December 29, 2018 111,658,927 3,435,518 115,094,445 97.0 % Exchanges during period 185,861 (185,861 ) — Stock option exercises 1,065,446 — 1,065,446 Other equity transactions 399,151 — 399,151 Balance — December 28, 2019 113,309,385 3,249,657 116,559,042 97.2 %
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 income (loss) Balance — December 30, 2017 $ 2,364 $ 4,637 $ 385 $ 7,386 Postretirement liability adjustment, net of tax 1,209 — — 1,209 Foreign currency translation adjustment, net of tax — (6,784 ) — (6,784 ) Income on cash flow hedges, net of tax — — 870 870 Balance — December 29, 2018 $ 3,573 $ (2,147 ) $ 1,255 $ 2,681 Postretirement liability adjustment, net of tax (1,402 ) — — (1,402 ) Foreign currency translation adjustment, net of tax — 3,424 — 3,424 Loss on cash flow hedges, net of tax — — (1,255 ) (1,255 ) Balance — December 28, 2019 $ 2,171 $ 1,277 $ — $ 3,448
Summit Materials, LLC
Company Information
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 income (loss) Balance — December 30, 2017 $ (6,053 ) $ (10,022 ) $ (1,060 ) $ (17,135 ) Postretirement liability adjustment 1,661 — — 1,661 Foreign currency translation adjustment — (9,348 ) — (9,348 ) Income on cash flow hedges — — 1,206 1,206 Balance — December 29, 2018 $ (4,392 ) $ (19,370 ) $ 146 $ (23,616 ) Postretirement liability adjustment (1,925 ) — — (1,925 ) Foreign currency translation adjustment — 4,716 — 4,716 Loss on cash flow hedges — — (146 ) (146 ) Balance — December 28, 2019 $ (6,317 ) $ (14,654 ) $ — $ (20,971 )

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 28, 2019
Schedule Of Cash Flow Supplemental [Line Items]
Schedule of Supplemental Cash Flow Information	Supplemental cash flow information for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 was as follows: 2019 2018 2017 Cash payments: Interest $ 104,614 $ 103,250 $ 96,320 (Refund) payments for income taxes, net (919 ) 3,340 1,711 Operating cash payments on operating leases 10,618 N/A N/A Operating cash payments on finance leases 3,051 N/A N/A Finance cash payments on finance leases 13,164 N/A N/A Non cash financing activities: Purchase of noncontrolling interest $ — $ — $ (716 ) Stock Dividend — — (45,023 ) Right of use assets obtained in exchange for operating lease obligations 5,842 N/A N/A Right of use assets obtained in exchange for finance leases obligations 23,965 N/A N/A Exchange of LP Units to shares of Class A common stock 3,847 7,499 41,126
Summit Materials, LLC
Schedule Of Cash Flow Supplemental [Line Items]
Schedule of Supplemental Cash Flow Information	Supplemental cash flow information for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 was as follows: 2019 2018 2017 Cash payments: Interest $ 104,614 $ 103,250 $ 96,320 (Refund) payments for income taxes, net (919 ) 3,340 1,711 Operating cash payments on operating leases 10,618 N/A N/A Operating cash payments on finance leases 3,051 N/A N/A Finance cash payments on finance leases 13,164 N/A N/A Non cash financing activities: Right of use assets obtained in exchange for operating lease obligations $ 5,842 N/A N/A Right of use assets obtained in exchange for finance leases obligations 23,965 N/A N/A Purchase of noncontrolling interest — — (716 )

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 28, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Information for the Equity Awards Granted	The following table summarizes information for the equity awards granted in 2019 : Options Restricted Stock Units Performance Stock Units Warrants Weighted Weighted Weighted Weighted average grant- Number of average grant- Number of average grant- average grant- Number of date fair value restricted date fair value performance date fair value Number of date fair value options per unit stock units per unit stock units per unit warrants per unit Beginning balance—December 29, 2018 3,267,149 $ 9.09 924,308 $ 24.57 295,252 $ 29.12 100,037 $ 18.00 Granted — — 1,238,530 17.60 242,007 26.20 — — Forfeited/ Canceled (73,596 ) 10.62 (176,152 ) 22.21 (146,614 ) 20.17 — — Exercised (1,065,446 ) 8.93 — — — — — — Vested — — (430,050 ) 23.71 — — — — Balance—December 28, 2019 2,128,107 $ 9.08 1,556,636 $ 21.17 390,645 $ 26.17 100,037 $ 18.00
Weighted Average Assumptions Used to Estimate the Fair Value of Grants	The following table presents the weighted average assumptions used to estimate the fair value of grants in 2019, 2018 and 2017 . No options to purchase common stock were granted in 2019 or 2018 : Options Performance Stock Units 2017 2019 2018 2017 Risk-free interest rate 2.06% - 2.31% 2.49% 2.38% 1.45% Dividend yield N/A N/A N/A N/A Volatility 47% 36% 38% 39% Expected term 7 years 3 years 3 years 3 years
Summit Materials, LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Information for the Equity Awards Granted	The following table summarizes information for the equity awards granted in 2019: Options Restricted Stock Units Performance Stock Units Warrants Weighted Weighted Weighted Weighted average grant- Number of average grant- Number of average grant- average grant- Number of date fair value restricted date fair value performance date fair value Number of date fair value options per unit stock units per unit stock units per unit warrants per unit Beginning balance—December 29, 2018 3,267,149 $ 9.09 924,308 $ 24.57 295,252 $ 29.12 100,037 $ 18.00 Granted — — 1,238,530 17.60 242,007 26.20 — — Forfeited/ Canceled (73,596 ) 10.62 (176,152 ) 22.21 (146,614 ) 20.17 — — Exercised (1,065,446 ) 8.93 — — — — — — Vested — — (430,050 ) 23.71 — — — — Balance—December 28, 2019 2,128,107 $ 9.08 1,556,636 $ 21.17 390,645 $ 26.17 100,037 $ 18.00
Weighted Average Assumptions Used to Estimate the Fair Value of Grants	The following table presents the weighted average assumptions used to estimate the fair value of grants in 2019, 2018 and 2017. No options to purchase common stock were granted in 2019 or 2018: Options Performance Stock Units 2017 2019 2018 2017 Risk-free interest rate 2.06% - 2.31% 2.49% 2.38% 1.45% Dividend yield N/A N/A N/A N/A Volatility 47% 36% 38% 39% Expected term 7 years 3 years 3 years 3 years

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 28, 2019
Defined Benefit Plan Disclosure [Line Items]
Obligations and Funded Status	The following information is as of December 28, 2019 and December 29, 2018 and for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 : 2019 2018 Pension Healthcare Pension Healthcare benefits & Life Ins. benefits & Life Ins. Change in benefit obligations: Beginning of period $ 24,203 $ 9,203 $ 27,984 $ 9,793 Service cost 60 166 67 170 Interest cost 928 321 898 317 Actuarial (gain) loss 2,571 165 (3,136 ) (173 ) Benefits paid (1,581 ) (765 ) (1,610 ) (904 ) End of period $ 26,181 $ 9,090 $ 24,203 $ 9,203 Change in fair value of plan assets: Beginning of period $ 17,449 $ — $ 19,012 $ — Actual return on plan assets 2,055 — (551 ) — Employer contributions 319 765 598 904 Benefits paid (1,581 ) (765 ) (1,610 ) (904 ) End of period $ 18,242 $ — $ 17,449 $ — Funded status of plans $ (7,939 ) $ (9,090 ) $ (6,754 ) $ (9,203 ) Current liabilities $ — $ (653 ) $ — $ (687 ) Noncurrent liabilities (7,939 ) (8,437 ) (6,754 ) (8,516 ) Liability recognized $ (7,939 ) $ (9,090 ) $ (6,754 ) $ (9,203 ) Amounts recognized in accumulated other comprehensive income: Net actuarial (gain) loss $ 9,286 $ 2,121 $ 7,728 $ 1,995 Prior service cost — (1,931 ) — (2,172 ) Total amount recognized $ 9,286 $ 190 $ 7,728 $ (177 )
Amounts Recognized in Other Comprehensive (Gain) Loss	The amount recognized in accumulated other comprehensive income (“AOCI”) is the actuarial loss (credit) and prior service cost, which has not yet been recognized in periodic benefit cost. 2019 2018 2017 Pension Healthcare Pension Healthcare Pension Healthcare benefits & Life Ins. benefits & Life Ins. benefits & Life Ins. Amounts recognized in other comprehensive (income) loss: Net actuarial loss (gain) $ 1,760 $ 165 $ (1,300 ) $ (172 ) $ 1,068 $ (338 ) Prior service cost — — — — — (572 ) Amortization of prior year service cost — 241 — 241 — 168 Curtailment benefit — — — — (429 ) — Amortization of gain (202 ) (39 ) (312 ) (118 ) (547 ) (64 ) Adjustment to plan benefits — — — — — (414 ) Total amount recognized $ 1,558 $ 367 $ (1,612 ) $ (49 ) $ 92 $ (1,220 )
Schedule of Net Benefit Costs	Components of net periodic benefit cost: Service cost $ 60 $ 166 $ 67 $ 170 $ 285 $ 184 Interest cost 928 321 898 317 998 365 Amortization of gain 202 39 312 118 547 64 Expected return on plan assets (1,244 ) — (1,284 ) — (1,302 ) — Amortization of prior service credit — (241 ) — (241 ) — (168 ) Net periodic (expense) benefit cost $ (54 ) $ 285 $ (7 ) $ 364 $ 528 $ 445
Schedule of Assumptions Used	Weighted-average assumptions used to determine the benefit obligations as of year-end 2019 and 2018 are: 2019 2018 Healthcare Healthcare Pension benefits & Life Ins. Pension benefits & Life Ins. Discount rate 2.78% - 2.96% 2.73% - 2.79% 3.90% - 4.02% 3.87% - 3.91% Expected long-term rate of return on plan assets 7.00% N/A 7.00% N/A Weighted-average assumptions used to determine net periodic benefit cost for years ended December 28, 2019 , December 29, 2018 and December 30, 2017 : 2019 2018 2017 Healthcare Healthcare Healthcare Pension benefits & Life Ins. Pension benefits & Life Ins. Pension benefits & Life Ins. Discount rate 3.90% - 4.02% 3.87% - 3.91% 3.23% - 3.37% 3.20% - 3.25% 3.61% - 3.81% 3.54% - 3.65% Expected long-term rate of return on plan assets 7.00% N/A 7.00% N/A 7.00% N/A
Effects of One Percentage-Point Change in Assumed Health Care Cost Trend Rates	A one percentage-point change in assumed health care cost trend rates would have the following effects as of year-end 2019 and 2018 : 2019 2018 Increase Decrease Increase Decrease Total service cost and interest cost components $ 30 $ (26 ) $ 31 $ (27 ) APBO 773 (678 ) 765 (690 )
Fair Value of Company's Pension Plans' Assets	The fair value of the Plans’ assets by asset class and fair value hierarchy level as of December 28, 2019 and December 29, 2018 are as follows: 2019 Quoted prices in active Total fair markets for identical Observable value assets (Level 1) inputs (Level 2) Fixed income securities: Intermediate—government $ 2,482 $ 2,482 $ — Intermediate—corporate 1,066 — 1,066 Short-term—government 1,387 1,387 — Short-term—corporate 3,173 — 3,173 International 1,387 — 1,387 Equity securities: U.S. Large cap value 1,225 1,225 — U.S. Large cap growth 1,167 1,167 — U.S. Mid cap value 581 581 — U.S. Mid cap growth 578 578 — U.S. Small cap value 583 583 — U.S. Small cap growth 593 593 — Managed Futures 340 — 340 International 1,174 386 788 Emerging Markets 394 394 — Commodities Broad Basket 1,118 362 756 Cash 994 994 — Total $ 18,242 $ 10,732 $ 7,510 2018 Quoted prices in active Total fair markets for identical Observable value assets (Level 1) inputs (Level 2) Fixed income securities: Intermediate—government $ 3,547 $ 3,547 $ — Intermediate—corporate 3,437 — 3,437 Short-term—government 756 756 — Short-term—corporate 957 — 957 International 1,143 — 1,143 Equity securities: U.S. Large cap value 978 978 — U.S. Large cap growth 976 976 — U.S. Mid cap value 471 471 — U.S. Mid cap growth 496 496 — U.S. Small cap value 463 463 — U.S. Small cap growth 474 474 — Managed Futures 355 — 355 International 1,004 329 675 Emerging Markets 362 362 — Commodities Broad Basket 1,048 388 660 Cash 982 982 — Total $ 17,449 $ 10,222 $ 7,227
Estimated Benefit Payments	The estimated benefit payments for each of the next five years and the five-year period thereafter are as follows: Pension Healthcare and Life benefits Insurance Benefits 2020 $ 1,718 $ 653 2021 1,681 638 2022 1,680 628 2023 1,679 618 2024 1,635 630 2025 - 2029 7,671 3,211
Schedule of Multiemployer Plans	Expiration Date of Pension Protection Act FIP/RP Status Contributions of Company Collective- Pension EIN/ Pension Zone Status Pending/ ($ in thousands) Surcharge Bargaining Trust Fund Plan Number 2019 2018 Implemented 2019 2018 Imposed Agreement Construction Industry Laborers Pension Fund 43-6060737/001 Green - as of December 31, 2018 Green - as of December 31, 2017 None $ 112 $ 115 No 3/31/2021 Operating Engineers Local 101 Pension Plan 43-6059213/001 Green - as of December 31, 2018 Green - as of December 31, 2017 None 23 26 No 3/31/2021 Total Contributions $ 135 $ 141
Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Obligations and Funded Status	The following information is as of December 28, 2019 and December 29, 2018 and for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 : 2019 2018 Pension Healthcare Pension Healthcare benefits & Life Ins. benefits & Life Ins. Change in benefit obligations: Beginning of period $ 24,203 $ 9,203 $ 27,984 $ 9,793 Service cost 60 166 67 170 Interest cost 928 321 898 317 Actuarial (gain) loss 2,571 165 (3,136 ) (173 ) Benefits paid (1,581 ) (765 ) (1,610 ) (904 ) End of period $ 26,181 $ 9,090 $ 24,203 $ 9,203 Change in fair value of plan assets: Beginning of period $ 17,449 $ — $ 19,012 $ — Actual return on plan assets 2,055 — (551 ) — Employer contributions 319 765 598 904 Benefits paid (1,581 ) (765 ) (1,610 ) (904 ) End of period $ 18,242 $ — $ 17,449 $ — Funded status of plans $ (7,939 ) $ (9,090 ) $ (6,754 ) $ (9,203 ) Current liabilities $ — $ (653 ) $ — $ (687 ) Noncurrent liabilities (7,939 ) (8,437 ) (6,754 ) (8,516 ) Liability recognized $ (7,939 ) $ (9,090 ) $ (6,754 ) $ (9,203 ) Amounts recognized in accumulated other comprehensive income: Net actuarial (gain) loss $ 9,286 $ 2,121 $ 7,728 $ 1,995 Prior service cost — (1,931 ) — (2,172 ) Total amount recognized $ 9,286 $ 190 $ 7,728 $ (177 )
Amounts Recognized in Other Comprehensive (Gain) Loss	2019 2018 2017 Pension Healthcare Pension Healthcare Pension Healthcare benefits & Life Ins. benefits & Life Ins. benefits & Life Ins. Amounts recognized in other comprehensive (income) loss: Net actuarial loss (gain) $ 1,760 $ 165 $ (1,300 ) $ (172 ) $ 1,068 $ (338 ) Prior service cost — — — — — (572 ) Amortization of prior year service cost — 241 — 241 — 168 Curtailment benefit — — — — (429 ) — Amortization of gain (202 ) (39 ) (312 ) (118 ) (547 ) (64 ) Adjustment to plan benefits — — — — — (414 ) Total amount recognized $ 1,558 $ 367 $ (1,612 ) $ (49 ) $ 92 $ (1,220 ) Components of net periodic benefit cost: Service cost $ 60 $ 166 $ 67 $ 170 $ 285 $ 184 Interest cost 928 321 898 317 998 365 Amortization of gain 202 39 312 118 547 64 Expected return on plan assets (1,244 ) — (1,284 ) — (1,302 ) — Amortization of prior service credit — (241 ) — (241 ) — (168 ) Net periodic (expense) benefit cost $ (54 ) $ 285 $ (7 ) $ 364 $ 528 $ 445
Schedule of Assumptions Used	Weighted-average assumptions used to determine the benefit obligations as of year-end 2019 and 2018 are: 2019 2018 Healthcare Healthcare Pension benefits & Life Ins. Pension benefits & Life Ins. Discount rate 2.78% - 2.96% 2.73% - 2.79% 3.90% - 4.02% 3.87% - 3.91% Expected long-term rate of return on plan assets 7.00% N/A 7.00% N/A Weighted-average assumptions used to determine net periodic benefit cost for years ended December 28, 2019 , December 29, 2018 and December 30, 2017 : 2019 2018 2017 Healthcare Healthcare Healthcare Pension benefits & Life Ins. Pension benefits & Life Ins. Pension benefits & Life Ins. Discount rate 3.90% - 4.02% 3.87% - 3.91% 3.23% - 3.37% 3.20% - 3.25% 3.61% - 3.81% 3.54% - 3.65% Expected long-term rate of return on plan assets 7.00% N/A 7.00% N/A 7.00% N/A
Effects of One Percentage-Point Change in Assumed Health Care Cost Trend Rates	A one percentage-point change in assumed health care cost trend rates would have the following effects as of year-end 2019 and 2018 : 2019 2018 Increase Decrease Increase Decrease Total service cost and interest cost components $ 30 $ (26 ) $ 31 $ (27 ) APBO 773 (678 ) 765 (690 )
Fair Value of Company's Pension Plans' Assets	The fair value of the Plans’ assets by asset class and fair value hierarchy level as of December 28, 2019 and December 29, 2018 are as follows: 2019 Quoted prices in active Total fair markets for identical Observable value assets (Level 1) inputs (Level 2) Fixed income securities: Intermediate—government $ 2,482 $ 2,482 $ — Intermediate—corporate 1,066 — 1,066 Short-term—government 1,387 1,387 — Short-term—corporate 3,173 — 3,173 International 1,387 — 1,387 Equity securities: U.S. Large cap value 1,225 1,225 — U.S. Large cap growth 1,167 1,167 — U.S. Mid cap value 581 581 — U.S. Mid cap growth 578 578 — U.S. Small cap value 583 583 — U.S. Small cap growth 593 593 — Managed Futures 340 — 340 International 1,174 386 788 Emerging Markets 394 394 — Commodities Broad Basket 1,118 362 756 Cash 994 994 — Total $ 18,242 $ 10,732 $ 7,510 2018 Quoted prices in active Total fair markets for identical Observable value assets (Level 1) inputs (Level 2) Fixed income securities: Intermediate—government $ 3,547 $ 3,547 $ — Intermediate—corporate 3,437 — 3,437 Short-term—government 756 756 — Short-term—corporate 957 — 957 International 1,143 — 1,143 Equity securities: U.S. Large cap value 978 978 — U.S. Large cap growth 976 976 — U.S. Mid cap value 471 471 — U.S. Mid cap growth 496 496 — U.S. Small cap value 463 463 — U.S. Small cap growth 474 474 — Managed Futures 355 — 355 International 1,004 329 675 Emerging Markets 362 362 — Commodities Broad Basket 1,048 388 660 Cash 982 982 — Total $ 17,449 $ 10,222 $ 7,227
Estimated Benefit Payments	The estimated benefit payments for each of the next five years and the five-year period thereafter are as follows: Pension Healthcare and Life benefits Insurance Benefits 2020 $ 1,718 $ 653 2021 1,681 638 2022 1,680 628 2023 1,679 618 2024 1,635 630 2025 - 2029 7,671 3,211
Schedule of Multiemployer Plans	Expiration Date of Pension Protection Act FIP/RP Status Contributions of Company Collective- Pension EIN/ Pension Zone Status Pending/ ($ in thousands) Surcharge Bargaining Trust Fund Plan Number 2019 2018 Implemented 2019 2018 Imposed Agreement Construction Industry Laborers Pension Fund 43-6060737/001 Green - as of December 31, 2018 Green - as of December 31, 2017 None $ 112 $ 115 No 3/31/2021 Operating Engineers Local 101 Pension Plan 43-6059213/001 Green - as of December 31, 2018 Green - as of December 31, 2017 None 23 26 No 3/31/2021 Total Contributions $ 135 $ 141

Accrued Mining and Landfill R_2

Accrued Mining and Landfill Reclamation (Tables)	12 Months Ended
	Dec. 28, 2019
Asset Retirement Obligations [Line Items]
Activity for Asset Retirement Obligations	The following table presents the activity for the asset retirement obligations for the years ended December 28, 2019 and December 29, 2018 : 2019 2018 Beginning balance $ 30,999 $ 24,329 Acquired obligations 805 3,937 Change in cost estimate 4,468 2,808 Settlement of reclamation obligations (1,812 ) (1,680 ) Accretion expense 2,216 1,605 Ending balance $ 36,676 $ 30,999
Summit Materials, LLC
Asset Retirement Obligations [Line Items]
Activity for Asset Retirement Obligations	The following table presents the activity for the asset retirement obligations for the years ended December 28, 2019 and December 29, 2018 : 2019 2018 Beginning balance $ 30,999 $ 24,329 Acquired obligations 805 3,937 Change in cost estimate 4,468 2,808 Settlement of reclamation obligations (1,812 ) (1,680 ) Accretion expense 2,216 1,605 Ending balance $ 36,676 $ 30,999

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 28, 2019
Lessee, Lease, Description [Line Items]
Schedule of Lease Cost	The components of lease expense were as follows: 2019 Operating lease cost $ 10,451 Variable lease cost 423 Short-term lease cost 38,417 Financing lease cost: Amortization of right-of-use assets 11,062 Interest on lease liabilities 3,171 Total lease cost $ 63,524 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 32,777 Current operating lease liabilities $ 8,427 Noncurrent operating lease liabilities 25,381 Total operating lease liabilities $ 33,808 Finance leases: Property and equipment, gross $ 82,660 Less accumulated depreciation (24,907 ) Property and equipment, net $ 57,753 Current finance lease liabilities $ 16,007 Long-term finance lease liabilities 40,410 Total finance lease liabilities $ 56,417 2019 Lease Term Discount Rate (years) (%) Weighted average: Operating leases 8.6 5.5 % Finance lease 2.6 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 $ 9,958 $ 18,646 2021 7,960 21,886 2022 4,852 14,940 2023 3,842 1,732 2024 2,246 2,252 Thereafter 14,292 2,829 Total lease payments 43,150 62,285 Less imputed interest (9,342 ) (5,868 ) Present value of lease payments $ 33,808 $ 56,417
Schedule of Lease Assets and Liabilities	The components of lease expense were as follows: 2019 Operating lease cost $ 10,451 Variable lease cost 423 Short-term lease cost 38,417 Financing lease cost: Amortization of right-of-use assets 11,062 Interest on lease liabilities 3,171 Total lease cost $ 63,524 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 32,777 Current operating lease liabilities $ 8,427 Noncurrent operating lease liabilities 25,381 Total operating lease liabilities $ 33,808 Finance leases: Property and equipment, gross $ 82,660 Less accumulated depreciation (24,907 ) Property and equipment, net $ 57,753 Current finance lease liabilities $ 16,007 Long-term finance lease liabilities 40,410 Total finance lease liabilities $ 56,417 2019 Lease Term Discount Rate (years) (%) Weighted average: Operating leases 8.6 5.5 % Finance lease 2.6 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 $ 9,958 $ 18,646 2021 7,960 21,886 2022 4,852 14,940 2023 3,842 1,732 2024 2,246 2,252 Thereafter 14,292 2,829 Total lease payments 43,150 62,285 Less imputed interest (9,342 ) (5,868 ) Present value of lease payments $ 33,808 $ 56,417
Schedule of Finance Lease Liability Maturities	The components of lease expense were as follows: 2019 Operating lease cost $ 10,451 Variable lease cost 423 Short-term lease cost 38,417 Financing lease cost: Amortization of right-of-use assets 11,062 Interest on lease liabilities 3,171 Total lease cost $ 63,524 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 32,777 Current operating lease liabilities $ 8,427 Noncurrent operating lease liabilities 25,381 Total operating lease liabilities $ 33,808 Finance leases: Property and equipment, gross $ 82,660 Less accumulated depreciation (24,907 ) Property and equipment, net $ 57,753 Current finance lease liabilities $ 16,007 Long-term finance lease liabilities 40,410 Total finance lease liabilities $ 56,417 2019 Lease Term Discount Rate (years) (%) Weighted average: Operating leases 8.6 5.5 % Finance lease 2.6 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 $ 9,958 $ 18,646 2021 7,960 21,886 2022 4,852 14,940 2023 3,842 1,732 2024 2,246 2,252 Thereafter 14,292 2,829 Total lease payments 43,150 62,285 Less imputed interest (9,342 ) (5,868 ) Present value of lease payments $ 33,808 $ 56,417
Schedule of Operating Lease Liability Maturities	The components of lease expense were as follows: 2019 Operating lease cost $ 10,451 Variable lease cost 423 Short-term lease cost 38,417 Financing lease cost: Amortization of right-of-use assets 11,062 Interest on lease liabilities 3,171 Total lease cost $ 63,524 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 32,777 Current operating lease liabilities $ 8,427 Noncurrent operating lease liabilities 25,381 Total operating lease liabilities $ 33,808 Finance leases: Property and equipment, gross $ 82,660 Less accumulated depreciation (24,907 ) Property and equipment, net $ 57,753 Current finance lease liabilities $ 16,007 Long-term finance lease liabilities 40,410 Total finance lease liabilities $ 56,417 2019 Lease Term Discount Rate (years) (%) Weighted average: Operating leases 8.6 5.5 % Finance lease 2.6 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 $ 9,958 $ 18,646 2021 7,960 21,886 2022 4,852 14,940 2023 3,842 1,732 2024 2,246 2,252 Thereafter 14,292 2,829 Total lease payments 43,150 62,285 Less imputed interest (9,342 ) (5,868 ) Present value of lease payments $ 33,808 $ 56,417
Schedule of Future Minimum Rental Payments for Operating Leases	Minimum contractual commitments for the subsequent five years under royalty agreements are as follows: Royalty Agreements 2020 $ 7,555 2021 7,212 2022 7,214 2023 7,216 2024 6,613
Summit Materials, LLC
Lessee, Lease, Description [Line Items]
Schedule of Lease Cost	The components of lease expense were as follows: 2019 Operating lease cost $ 10,451 Variable lease cost 423 Short-term lease cost 38,417 Financing lease cost: Amortization of right-of-use assets 11,062 Interest on lease liabilities 3,171 Total lease cost $ 63,524 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 32,777 Current operating lease liabilities $ 8,427 Noncurrent operating lease liabilities 25,381 Total operating lease liabilities $ 33,808 Finance leases: Property and equipment, gross $ 82,660 Less accumulated depreciation (24,907 ) Property and equipment, net $ 57,753 Current finance lease liabilities $ 16,007 Long-term finance lease liabilities 40,410 Total finance lease liabilities $ 56,417 2019 Lease Term Discount Rate (years) (%) Weighted average: Operating leases 8.6 5.5 % Finance lease 2.6 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 $ 9,958 $ 18,646 2021 7,960 21,886 2022 4,852 14,940 2023 3,842 1,732 2024 2,246 2,252 Thereafter 14,292 2,829 Total lease payments 43,150 62,285 Less imputed interest (9,342 ) (5,868 ) Present value of lease payments $ 33,808 $ 56,417
Schedule of Lease Assets and Liabilities	The components of lease expense were as follows: 2019 Operating lease cost $ 10,451 Variable lease cost 423 Short-term lease cost 38,417 Financing lease cost: Amortization of right-of-use assets 11,062 Interest on lease liabilities 3,171 Total lease cost $ 63,524 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 32,777 Current operating lease liabilities $ 8,427 Noncurrent operating lease liabilities 25,381 Total operating lease liabilities $ 33,808 Finance leases: Property and equipment, gross $ 82,660 Less accumulated depreciation (24,907 ) Property and equipment, net $ 57,753 Current finance lease liabilities $ 16,007 Long-term finance lease liabilities 40,410 Total finance lease liabilities $ 56,417 2019 Lease Term Discount Rate (years) (%) Weighted average: Operating leases 8.6 5.5 % Finance lease 2.6 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 $ 9,958 $ 18,646 2021 7,960 21,886 2022 4,852 14,940 2023 3,842 1,732 2024 2,246 2,252 Thereafter 14,292 2,829 Total lease payments 43,150 62,285 Less imputed interest (9,342 ) (5,868 ) Present value of lease payments $ 33,808 $ 56,417
Schedule of Finance Lease Liability Maturities	The components of lease expense were as follows: 2019 Operating lease cost $ 10,451 Variable lease cost 423 Short-term lease cost 38,417 Financing lease cost: Amortization of right-of-use assets 11,062 Interest on lease liabilities 3,171 Total lease cost $ 63,524 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 32,777 Current operating lease liabilities $ 8,427 Noncurrent operating lease liabilities 25,381 Total operating lease liabilities $ 33,808 Finance leases: Property and equipment, gross $ 82,660 Less accumulated depreciation (24,907 ) Property and equipment, net $ 57,753 Current finance lease liabilities $ 16,007 Long-term finance lease liabilities 40,410 Total finance lease liabilities $ 56,417 2019 Lease Term Discount Rate (years) (%) Weighted average: Operating leases 8.6 5.5 % Finance lease 2.6 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 $ 9,958 $ 18,646 2021 7,960 21,886 2022 4,852 14,940 2023 3,842 1,732 2024 2,246 2,252 Thereafter 14,292 2,829 Total lease payments 43,150 62,285 Less imputed interest (9,342 ) (5,868 ) Present value of lease payments $ 33,808 $ 56,417
Schedule of Operating Lease Liability Maturities	The components of lease expense were as follows: 2019 Operating lease cost $ 10,451 Variable lease cost 423 Short-term lease cost 38,417 Financing lease cost: Amortization of right-of-use assets 11,062 Interest on lease liabilities 3,171 Total lease cost $ 63,524 2019 Supplemental balance sheet information related to leases: Operating leases: Operating lease right-of-use assets $ 32,777 Current operating lease liabilities $ 8,427 Noncurrent operating lease liabilities 25,381 Total operating lease liabilities $ 33,808 Finance leases: Property and equipment, gross $ 82,660 Less accumulated depreciation (24,907 ) Property and equipment, net $ 57,753 Current finance lease liabilities $ 16,007 Long-term finance lease liabilities 40,410 Total finance lease liabilities $ 56,417 2019 Lease Term Discount Rate (years) (%) Weighted average: Operating leases 8.6 5.5 % Finance lease 2.6 5.5 % Maturities of lease liabilities were as follows: Operating Leases Finance Leases 2020 $ 9,958 $ 18,646 2021 7,960 21,886 2022 4,852 14,940 2023 3,842 1,732 2024 2,246 2,252 Thereafter 14,292 2,829 Total lease payments 43,150 62,285 Less imputed interest (9,342 ) (5,868 ) Present value of lease payments $ 33,808 $ 56,417
Schedule of Future Minimum Rental Payments for Operating Leases	Minimum contractual commitments for the subsequent five years under royalty agreements are as follows: Royalty Agreements 2020 $ 7,555 2021 7,212 2022 7,214 2023 7,216 2024 6,613

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 28, 2019
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 and derivatives as of December 28, 2019 and December 29, 2018 was: 2019 2018 Current portion of acquisition-related liabilities and Accrued expenses: Contingent consideration $ 1,967 $ 1,394 Cash flow hedges — — Acquisition-related liabilities and Other noncurrent liabilities: Contingent consideration $ 1,302 $ 5,175 Cash flow hedges — —
Schedule of Carrying Value and Fair Value of Financial Instruments	The carrying value and fair value of these financial instruments as of December 28, 2019 and December 29, 2018 were: December 28, 2019 December 29, 2018 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt(1) $ 1,918,720 $ 1,872,273 $ 1,777,722 $ 1,828,159 Level 3 Current portion of deferred consideration and noncompete obligations(2) 30,733 30,733 32,876 32,876 Long term portion of deferred consideration and noncompete obligations(3) 18,499 18,499 44,293 44,293 _____________________ (1) $7.9 million and $6.4 million were included in current portion of debt as of December 28, 2019 and December 29, 2018 , respectively. (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 and derivatives as of December 28, 2019 and December 29, 2018 was: 2019 2018 Current portion of acquisition-related liabilities and Accrued expenses: Contingent consideration $ 1,967 $ 1,394 Cash flow hedges — — Acquisition-related liabilities and Other noncurrent liabilities: Contingent consideration $ 1,302 $ 5,175 Cash flow hedges — —
Schedule of Carrying Value and Fair Value of Financial Instruments	The carrying value and fair value of these financial instruments as of December 28, 2019 and December 29, 2018 were: December 28, 2019 December 29, 2018 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt(1) $ 1,918,720 $ 1,872,273 $ 1,777,722 $ 1,828,159 Level 3 Current portion of deferred consideration and noncompete obligations(2) 28,233 28,233 30,376 30,376 Long term portion of deferred consideration and noncompete obligations(3) 16,364 16,364 40,179 40,179 ______________________ (1) $7.9 million and $6.4 million were included in current portion of debt as of December 28, 2019 and December 29, 2018 , respectively. (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)	12 Months Ended
	Dec. 28, 2019
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 and for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 : 2019 2018 2017 Revenue*: West $ 1,122,338 $ 1,117,066 $ 998,843 East 809,098 703,147 629,919 Cement 290,704 280,789 303,813 Total revenue $ 2,222,140 $ 2,101,002 $ 1,932,575 ______________________ * Intercompany sales are immaterial and the presentation above only reflects sales to external customers. 2019 2018 2017 Income (loss) from operations before taxes $ 78,224 $ 96,077 $ (158,200 ) Interest expense 116,509 116,548 108,549 Depreciation, depletion and amortization 214,886 203,305 177,643 Accretion 2,216 1,605 1,875 Loss on debt financings 14,565 149 4,815 Tax receivable agreement expense (benefit) 16,237 (22,684 ) 271,016 Gain on sale of business — (12,108 ) — Transaction costs 2,222 4,238 7,733 Non-cash compensation 20,403 25,378 21,140 Other (3,800 ) (6,247 ) 1,206 Total Adjusted EBITDA $ 461,462 $ 406,261 $ 435,777 Total Adjusted EBITDA by Segment: West $ 204,964 $ 188,999 $ 203,590 East 187,625 138,032 139,108 Cement 103,438 111,394 127,547 Corporate and other (34,565 ) (32,164 ) (34,468 ) Total Adjusted EBITDA $ 461,462 $ 406,261 $ 435,777 2019 2018 2017 Purchases of property, plant and equipment West $ 71,397 $ 120,657 $ 83,591 East 77,894 64,384 68,556 Cement 25,691 28,036 35,803 Total reportable segments 174,982 213,077 187,950 Corporate and other 2,513 7,608 6,196 Total purchases of property, plant and equipment $ 177,495 $ 220,685 $ 194,146 2019 2018 2017 Depreciation, depletion, amortization and accretion: West $ 93,256 $ 91,794 $ 71,314 East 81,403 75,433 67,252 Cement 38,447 35,061 38,351 Total reportable segments 213,106 202,288 176,917 Corporate and other 3,996 2,622 2,601 Total depreciation, depletion, amortization and accretion $ 217,102 $ 204,910 $ 179,518 2019 2018 2017 Total assets: West $ 1,379,684 $ 1,370,501 $ 1,225,463 East 1,288,835 1,253,640 1,035,609 Cement 868,528 877,586 870,652 Total reportable segments 3,537,047 3,501,727 3,131,724 Corporate and other 530,509 355,914 655,609 Total $ 4,067,556 $ 3,857,641 $ 3,787,333
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 and for the years ended December 28, 2019 , December 29, 2018 and December 30, 2017 : 2019 2018 2017 Revenue*: West $ 1,122,338 $ 1,117,066 $ 998,843 East 809,098 703,147 629,919 Cement 290,704 280,789 303,813 Total revenue $ 2,222,140 $ 2,101,002 $ 1,932,575 ______________________ * Intercompany sales are immaterial and the presentation above only reflects sales to external customers. 2019 2018 2017 Income (loss) from operations before taxes $ 94,982 $ 74,110 $ 113,696 Interest expense 115,988 115,831 107,655 Depreciation, depletion and amortization 214,886 203,305 177,643 Accretion 2,216 1,605 1,875 Loss on debt financings 14,565 149 4,815 Gain on sale of business — (12,108 ) — Transaction costs 2,222 4,238 7,733 Non-cash compensation 20,403 25,378 21,140 Other (3,800 ) (6,247 ) 1,206 Total Adjusted EBITDA $ 461,462 $ 406,261 $ 435,763 Total Adjusted EBITDA by Segment: West $ 204,964 $ 188,999 $ 203,590 East 187,625 138,032 139,108 Cement 103,438 111,394 127,547 Corporate and other (34,565 ) (32,164 ) (34,482 ) Total Adjusted EBITDA $ 461,462 $ 406,261 $ 435,763 2019 2018 2017 Purchases of property, plant and equipment West $ 71,397 $ 120,657 $ 83,591 East 77,894 64,384 68,556 Cement 25,691 28,036 35,803 Total reportable segments 174,982 213,077 187,950 Corporate and other 2,513 7,608 6,196 Total purchases of property, plant and equipment $ 177,495 $ 220,685 $ 194,146 2019 2018 2017 Depreciation, depletion, amortization and accretion: West $ 93,256 $ 91,794 $ 71,314 East 81,403 75,433 67,252 Cement 38,447 35,061 38,351 Total reportable segments 213,106 202,288 176,917 Corporate and other 3,996 2,622 2,601 Total depreciation, depletion, amortization and accretion $ 217,102 $ 204,910 $ 179,518 2019 2018 2017 Total assets: West $ 1,379,684 $ 1,370,501 $ 1,225,463 East 1,288,835 1,253,640 1,035,609 Cement 868,528 877,586 870,652 Total reportable segments 3,537,047 3,501,727 3,131,724 Corporate and other 319,176 131,517 372,517 Total $ 3,856,223 $ 3,633,244 $ 3,504,241

Senior Notes' Guarantor and N_2

Senior Notes' Guarantor and Non-Guarantor Financial Information (Tables) - Summit Materials, LLC	12 Months Ended
	Dec. 28, 2019
Condensed Financial Statements, Captions [Line Items]
Condensed Consolidating Balance Sheets	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 Balance Sheets December 29, 2018 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Assets Current assets: Cash and cash equivalents $ 117,219 $ 8,440 $ 7,719 $ (4,870 ) $ 128,508 Accounts receivable, net — 199,538 15,165 (185 ) 214,518 Intercompany receivables 500,765 624,427 — (1,125,192 ) — Cost and estimated earnings in excess of billings — 17,711 891 — 18,602 Inventories — 210,149 3,702 — 213,851 Other current assets 1,953 11,308 2,800 — 16,061 Total current assets 619,937 1,071,573 30,277 (1,130,247 ) 591,540 Property, plant and equipment, net 13,300 1,709,083 57,749 — 1,780,132 Goodwill — 1,136,785 56,243 — 1,193,028 Intangible assets, net — 18,460 — — 18,460 Other assets 3,292,851 154,080 947 (3,397,794 ) 50,084 Total assets $ 3,926,088 $ 4,089,981 $ 145,216 $ (4,528,041 ) $ 3,633,244 Liabilities and Member’s Interest Current liabilities: Current portion of debt $ 6,354 $ — $ — $ — $ 6,354 Current portion of acquisition-related liabilities — 31,770 — — 31,770 Accounts payable 4,712 92,132 12,349 (185 ) 109,008 Accrued expenses 45,146 57,826 1,927 (4,870 ) 100,029 Intercompany payables 673,175 436,564 15,453 (1,125,192 ) — Billings in excess of costs and estimated earnings — 11,347 493 — 11,840 Total current liabilities 729,387 629,639 30,222 (1,130,247 ) 259,001 Long-term debt 1,807,502 — — — 1,807,502 Acquisition-related liabilities — 45,354 — — 45,354 Other noncurrent liabilities 3,768 226,137 77,368 (171,317 ) 135,956 Total liabilities 2,540,657 901,130 107,590 (1,301,564 ) 2,247,813 Total member's interest 1,385,431 3,188,851 37,626 (3,226,477 ) 1,385,431 Total liabilities and member’s interest $ 3,926,088 $ 4,089,981 $ 145,216 $ (4,528,041 ) $ 3,633,244
Condensed Consolidating Statements of Operations and Comprehensive Loss	Condensed Consolidating Statements of Operations and Comprehensive Income Year Ended December 28, 2019 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 2,139,457 $ 94,879 $ (12,196 ) $ 2,222,140 Cost of revenue (excluding items shown separately below) — 1,473,124 65,404 (12,196 ) 1,526,332 General and administrative expenses 58,099 195,683 11,366 — 265,148 Depreciation, depletion, amortization and accretion 3,997 207,277 5,828 — 217,102 Operating (loss) income (62,096 ) 263,373 12,281 — 213,558 Other (income) loss, net (279,517 ) (8,767 ) (790 ) 291,662 2,588 Interest expense (income) 127,734 (16,561 ) 4,815 — 115,988 Income from operation before taxes 89,687 288,701 8,256 (291,662 ) 94,982 Income tax expense 1,090 3,377 1,918 — 6,385 Net income attributable to Summit LLC $ 88,597 $ 285,324 $ 6,338 $ (291,662 ) $ 88,597 Comprehensive income attributable to member of Summit Materials, LLC $ 91,242 $ 287,395 $ 1,622 $ (289,017 ) $ 91,242 Condensed Consolidating Statements of Operations and Comprehensive Income Year ended December 29, 2018 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 2,018,428 $ 88,658 $ (6,084 ) $ 2,101,002 Cost of revenue (excluding items shown separately below) — 1,416,222 65,641 (6,084 ) 1,475,779 General and administrative expenses 62,376 184,917 10,554 — 257,847 Depreciation, depletion, amortization and accretion 2,622 197,406 4,882 — 204,910 Operating (loss) income (64,998 ) 219,883 7,581 — 162,466 Other (income) loss, net (249,204 ) (14,643 ) 823 247,657 (15,367 ) Interest expense (income) 118,857 (7,818 ) 4,792 — 115,831 Gain on sale of business — (12,108 ) — — (12,108 ) Income from operation before taxes 65,349 254,452 1,966 (247,657 ) 74,110 Income tax expense 1,512 8,226 535 — 10,273 Net income attributable to Summit LLC $ 63,837 $ 246,226 $ 1,431 $ (247,657 ) $ 63,837 Comprehensive income attributable to member of Summit Materials, LLC $ 57,356 $ 243,359 $ 10,779 $ (254,138 ) $ 57,356 Condensed Consolidating Statements of Operations and Comprehensive Income Year ended December 30, 2017 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Revenue $ — $ 1,854,434 $ 84,020 $ (5,879 ) $ 1,932,575 Cost of revenue (excluding items shown separately below) — 1,227,037 60,619 (5,879 ) 1,281,777 General and administrative expenses 63,954 178,023 8,426 — 250,403 Depreciation, depletion, amortization and accretion 2,601 172,738 4,179 — 179,518 Operating (loss) income (66,555 ) 276,636 10,796 — 220,877 Other (income) loss, net (307,876 ) (1,925 ) (533 ) 309,860 (474 ) Interest expense 105,735 (2,415 ) 4,335 — 107,655 Income from continuing operations before taxes 135,586 280,976 6,994 (309,860 ) 113,696 Income tax (benefit) expense 1,518 (23,774 ) 1,911 — (20,345 ) Net income 134,068 304,750 5,083 (309,860 ) 134,041 Net income attributable to noncontrolling interest — — — (27 ) (27 ) Net income attributable to member of Summit Materials, LLC $ 134,068 $ 304,750 $ 5,083 $ (309,833 ) $ 134,068 Comprehensive income attributable to member of Summit Materials, LLC $ 144,377 $ 302,209 $ (2,685 ) $ (299,524 ) $ 144,377
Condensed Consolidating Statements of Cash Flows	Condensed Consolidating Statements of Cash Flows For the year ended December 28, 2019 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Net cash (used in) provided by operating activities $ (112,019 ) $ 431,323 $ 17,880 $ — $ 337,184 Cash flow from investing activities: Acquisitions, net of cash acquired — (5,392 ) — — (5,392 ) Purchase of property, plant and equipment (2,513 ) (163,652 ) (11,330 ) — (177,495 ) Proceeds from the sale of property, plant, and equipment — 21,083 90 — 21,173 Other — (1,095 ) — — (1,095 ) Net cash used for investing activities (2,513 ) (149,056 ) (11,240 ) — (162,809 ) Cash flow from financing activities: Proceeds from investment by member (21,614 ) 40,690 — — 19,076 Net proceeds from debt issuance 300,000 — — — 300,000 Loans received from and payments made on loans from other Summit Companies 287,029 (280,836 ) (4,586 ) (1,607 ) — Payments on long-term debt (256,354 ) (13,650 ) (225 ) — (270,229 ) Payments on acquisition-related liabilities — (31,383 ) — — (31,383 ) Debt issuance costs (6,312 ) — — — (6,312 ) Distributions from partnership (2,500 ) — — — (2,500 ) Other (462 ) (40 ) — — (502 ) Net cash provided by (used in) financing activities 299,787 (285,219 ) (4,811 ) (1,607 ) 8,150 Impact of cash on foreign currency — — 286 — 286 Net increase (decrease) in cash 185,255 (2,952 ) 2,115 (1,607 ) 182,811 Cash — Beginning of period 117,219 8,440 7,719 (4,870 ) 128,508 Cash — End of period $ 302,474 $ 5,488 $ 9,834 $ (6,477 ) $ 311,319 Condensed Consolidating Statements of Cash Flows For the year ended December 29, 2018 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Net cash (used in) provided by operating activities $ (142,315 ) $ 340,401 $ 11,282 $ — $ 209,368 Cash flow from investing activities: Acquisitions, net of cash acquired — (246,017 ) — — (246,017 ) Purchase of property, plant and equipment (7,607 ) (188,435 ) (24,643 ) — (220,685 ) Proceeds from the sale of property, plant, and equipment — 21,263 372 — 21,635 Proceeds from the sale of a business — 21,564 — — 21,564 Other — 3,804 — — 3,804 Net cash used for investing activities (7,607 ) (387,821 ) (24,271 ) — (419,699 ) Cash flow from financing activities: Proceeds from investment by member (146,533 ) 162,148 — — 15,615 Net proceeds from debt issuance 64,500 — — — 64,500 Loans received from and payments made on loans from other Summit Companies 51,696 (65,845 ) 6,647 7,502 — Payments on long-term debt (69,265 ) (15,662 ) (115 ) — (85,042 ) Payments on acquisition-related liabilities — (34,004 ) — — (34,004 ) Financing costs (550 ) — — — (550 ) Distributions from partnership (2,569 ) — — — (2,569 ) Other (879 ) (1,031 ) (33 ) — (1,943 ) Net cash (used in) provided by financing activities (103,600 ) 45,606 6,499 7,502 (43,993 ) Impact of cash on foreign currency — — (724 ) — (724 ) Net decrease in cash (253,522 ) (1,814 ) (7,214 ) 7,502 (255,048 ) Cash — Beginning of period 370,741 10,254 14,933 (12,372 ) 383,556 Cash — End of period $ 117,219 $ 8,440 $ 7,719 $ (4,870 ) $ 128,508 Condensed Consolidating Statements of Cash Flows For the year ended December 30, 2017 100% Owned Non- Issuers Guarantors Guarantors Eliminations Consolidated Net cash (used in) provided by operating activities $ (127,102 ) $ 392,316 $ 29,918 $ — $ 295,132 Cash flow from investing activities: Acquisitions, net of cash acquired (24,538 ) (324,892 ) (25,500 ) — (374,930 ) Purchase of property, plant and equipment (6,196 ) (182,295 ) (5,655 ) — (194,146 ) Proceeds from the sale of property, plant, and equipment — 16,822 250 — 17,072 Other — (471 ) — — (471 ) Net cash used for investing activities (30,734 ) (490,836 ) (30,905 ) — (552,475 ) Cash flow from financing activities: Proceeds from investment by member 40,913 252,911 10,717 — 304,541 Capital issuance costs (627 ) — — — (627 ) Net proceeds from debt issuance 302,000 — — — 302,000 Loans received from and payments made on loans from other Summit Companies 119,858 (108,026 ) (10,126 ) (1,706 ) — Payments on long-term debt (8,463 ) (7,967 ) (8 ) — (16,438 ) Purchase of noncontrolling interests — (532 ) — — (532 ) Payments on acquisition-related liabilities — (32,150 ) — — (32,150 ) Financing costs (6,416 ) — — — (6,416 ) Distributions from partnership (51,986 ) — — — (51,986 ) Other (564 ) (282 ) (20 ) — (866 ) Net cash provided by financing activities 394,715 103,954 563 (1,706 ) 497,526 Impact of cash on foreign currency — — 701 — 701 Net (decrease) increase in cash 236,879 5,434 277 (1,706 ) 240,884 Cash — Beginning of period 133,862 4,820 14,656 (10,666 ) 142,672 Cash — End of period $ 370,741 $ 10,254 $ 14,933 $ (12,372 ) $ 383,556

Supplementary Data (Unaudited)

Supplementary Data (Unaudited) (Tables)	12 Months Ended
	Dec. 28, 2019
Quarterly Financial Information [Line Items]
Summary of Quarterly Data (Unaudited)	Supplemental financial information (unaudited) by quarter is shown below for the years ended December 28, 2019 and December 29, 2018 . 2019 2018 4Q 3Q 2Q 1Q 4Q 3Q 2Q 1Q Net revenue $ 506,259 $ 665,847 $ 552,591 $ 305,950 $ 445,090 $ 625,017 $ 549,235 $ 289,916 Operating income (loss) 59,926 130,881 80,422 (57,671 ) 28,545 108,167 77,279 (51,525 ) Net income (loss) 36,397 58,237 37,990 (71,501 ) (18,627 ) 73,992 36,913 (55,948 ) Net income (loss) attributable to Summit Inc. 35,671 55,757 36,410 (68,772 ) (19,163 ) 71,289 35,509 (53,729 ) Basic earnings (loss) per share attributable to Summit Inc. $ 0.32 $ 0.50 $ 0.32 $ (0.62 ) $ (0.17 ) $ 0.64 $ 0.32 $ (0.49 ) Diluted earnings (loss) per share attributable to Summit Inc. 0.31 0.48 0.32 (0.62 ) (0.17 ) 0.64 0.32 (0.49 )
Summit Materials, LLC
Quarterly Financial Information [Line Items]
Summary of Quarterly Data (Unaudited)	Supplemental financial information (unaudited) by quarter is shown below for the years ended December 28, 2019 and December 29, 2018 : 2019 2018 4Q 3Q 2Q 1Q 4Q 3Q 2Q 1Q Net revenue $ 506,259 $ 665,847 $ 552,591 $ 305,950 $ 445,090 $ 625,017 $ 549,235 $ 289,916 Operating income (loss) 59,926 130,881 80,422 (57,671 ) 28,545 108,167 77,279 (51,525 ) Net income (loss) 41,461 85,199 53,501 (91,564 ) (4,596 ) 90,427 46,602 (68,596 )

Summary of Organization and S_3

Summary of Organization and Significant Accounting Policies - General Information and Equity Offerings (Details)	12 Months Ended
	Dec. 28, 2019segmentstateplant	Dec. 30, 2017	Dec. 29, 2018
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements
Number of operating segments	3
Number of reportable segments	3
Number of states in which the entity operates | state	23
Summit Materials, LLC
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements
Number of operating segments	3
Number of reportable segments	3
Number of states in which the entity operates | state	23
Summit Materials, LLC | Ohio Valley Asphalt
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements
Noncontrolling interest elimination (as a percent)	20.00%
Summit Materials, LLC | Continental Cement
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements
Noncontrolling interest elimination (as a percent)	30.00%
Summit Holdings LP
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements
Voting power (as a percent)			100.00%
Cement Plant
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements
Number of plants | plant	2
Cement Plant | Summit Materials, LLC
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements
Number of plants | plant	2
Tax Receivable Agreement | Summit Holdings LP
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements
Percentage of benefits to be paid on tax receivable agreement	85.00%	85.00%
Minimum | Product
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements
Collection terms	30 days
Maximum | Product
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements
Collection terms	60 days
Maximum | Service
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements
Collection terms	90 days

Summary of Organization and S_4

Summary of Organization and Significant Accounting Policies - New Accounting Standards (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 30, 2018
New Accounting Standards
Operating lease right-of-use assets	$ 32,777
Operating lease liability	33,808
Accounting Standards Update 2016-02
New Accounting Standards
Operating lease right-of-use assets		$ 36,800
Operating lease liability		36,800
Summit Materials, LLC
New Accounting Standards
Operating lease right-of-use assets	32,777
Operating lease liability	$ 33,808
Summit Materials, LLC | Accounting Standards Update 2016-02
New Accounting Standards
Operating lease right-of-use assets		36,800
Operating lease liability		$ 36,800

Acquisitions - Acquisitions by

Acquisitions - Acquisitions by Region (Details) - acquistiion	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
West
Business Acquisition [Line Items]
Number of business acquisitions	2	5	6
East
Business Acquisition [Line Items]
Number of business acquisitions	0	7	8
Summit Materials, LLC | West
Business Acquisition [Line Items]
Number of business acquisitions	2	5	6
Summit Materials, LLC | East
Business Acquisition [Line Items]
Number of business acquisitions	0	7	8

Acquisitions - Summary of Asset

Acquisitions - Summary of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Business Acquisition [Line Items]
Goodwill	$ 1,199,699	$ 1,192,028	$ 1,036,320
Summit Materials, LLC
Business Acquisition [Line Items]
Goodwill	1,200,699	1,193,028	$ 1,037,320
Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Financial assets	0	14,769
Inventories	52	18,313
Property, plant and equipment	3,542	124,957
Intangible assets	0	3,175
Other assets	0	1,539
Financial liabilities	(36)	(13,529)
Other long-term liabilities	0	(8,125)
Net assets acquired	3,558	141,099
Goodwill	1,834	154,120
Purchase price	5,392	295,219
Acquisition-related liabilities	0	(49,202)
Net cash paid for acquisitions	5,392	246,017
Series of Individually Immaterial Business Acquisitions | Summit Materials, LLC
Business Acquisition [Line Items]
Financial assets	0	14,769
Inventories	52	18,313
Property, plant and equipment	3,542	124,957
Intangible assets	0	3,175
Other assets	0	1,539
Financial liabilities	(36)	(13,529)
Other long-term liabilities	0	(8,125)
Net assets acquired	3,558	141,099
Goodwill	1,834	154,120
Purchase price	5,392	295,219
Acquisition-related liabilities	0	(49,202)
Net cash paid for acquisitions	$ 5,392	$ 246,017

Acquisitions - Contractual Obli

Acquisitions - Contractual Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Minimum
Remaining payments on contractual obligations
Term of payment for deferred consideration		5 years
Maximum
Remaining payments on contractual obligations
Term of payment for deferred consideration		20 years
Noncompete and Deferred Consideration Agreements
Remaining payments on contractual obligations
2020	$ 31,708
2021	9,705
2022	3,411
2023	2,657
2024	2,620
Thereafter	7,020
Total scheduled payments	57,121
Present value adjustments	(7,889)
Total noncompete obligations and deferred consideration	$ 49,232
Summit Materials, LLC | Minimum
Remaining payments on contractual obligations
Term of payment for deferred consideration	5 years
Summit Materials, LLC | Maximum
Remaining payments on contractual obligations
Term of payment for deferred consideration	20 years
Summit Materials, LLC | Noncompete and Deferred Consideration Agreements
Remaining payments on contractual obligations
2020	$ 29,208
2021	7,205
2022	3,411
2023	2,657
2024	2,620
Thereafter	7,020
Total scheduled payments	52,121
Present value adjustments	(7,524)
Total noncompete obligations and deferred consideration	$ 44,597

Goodwill - Narrative (Details)

Goodwill - Narrative (Details)	12 Months Ended
	Dec. 28, 2019USD ($)reporting_unit	Dec. 31, 2016USD ($)	Jan. 02, 2016USD ($)
Goodwill
Number of reporting units with goodwill | reporting_unit	11
Goodwill, impairment loss | $	$ 0
Accumulated impairment losses | $		$ 68,200,000
Number of reporting units after Austin and Houston integration | reporting_unit	1
Summit Materials, LLC
Goodwill
Number of reporting units with goodwill | reporting_unit	11
Accumulated impairment losses | $			$ 68,200,000

Goodwill - Summary of Goodwill

Goodwill - Summary of Goodwill by Reportable Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Goodwill [Roll Forward]
Beginning balance	$ 1,192,028	$ 1,036,320
Acquisitions	5,278	160,579
Foreign currency translation adjustments	2,393	(4,871)
Ending balance	1,199,699	1,192,028
Summit Materials, LLC
Goodwill [Roll Forward]
Beginning balance	1,193,028	1,037,320
Acquisitions	5,278	160,579
Foreign currency translation adjustments	2,393	(4,871)
Ending balance	1,200,699	1,193,028
West
Goodwill [Roll Forward]
Beginning balance	580,567	526,290
Acquisitions	1,657	59,148
Foreign currency translation adjustments	2,393	(4,871)
Ending balance	584,617	580,567
West | Summit Materials, LLC
Goodwill [Roll Forward]
Beginning balance	581,567	527,290
Acquisitions	1,657	59,148
Foreign currency translation adjustments	2,393	(4,871)
Ending balance	585,617	581,567
East
Goodwill [Roll Forward]
Beginning balance	406,805	305,374
Acquisitions	3,621	101,431
Foreign currency translation adjustments	0	0
Ending balance	410,426	406,805
East | Summit Materials, LLC
Goodwill [Roll Forward]
Beginning balance	406,805	305,374
Acquisitions	3,621	101,431
Foreign currency translation adjustments	0	0
Ending balance	410,426	406,805
Cement
Goodwill [Roll Forward]
Beginning balance	204,656	204,656
Acquisitions	0	0
Foreign currency translation adjustments	0	0
Ending balance	204,656	204,656
Cement | Summit Materials, LLC
Goodwill [Roll Forward]
Beginning balance	204,656	204,656
Acquisitions	0	0
Foreign currency translation adjustments	0	0
Ending balance	$ 204,656	$ 204,656

Revenue Recognition - By Produc

Revenue Recognition - By Product (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Revenue from External Customer [Line Items]
Revenue	$ 506,259	$ 665,847	$ 552,591	$ 305,950	$ 445,090	$ 625,017	$ 549,235	$ 289,916	$ 2,222,140	$ 2,101,002	$ 1,932,575
Summit Materials, LLC
Revenue from External Customer [Line Items]
Revenue	$ 506,259	$ 665,847	$ 552,591	$ 305,950	$ 445,090	$ 625,017	$ 549,235	$ 289,916	2,222,140	2,101,002	1,932,575
Aggregates
Revenue from External Customer [Line Items]
Revenue									469,670	373,824	313,383
Aggregates | Summit Materials, LLC
Revenue from External Customer [Line Items]
Revenue									469,670	373,824	313,383
Cement
Revenue from External Customer [Line Items]
Revenue									266,235	258,876	282,041
Cement | Summit Materials, LLC
Revenue from External Customer [Line Items]
Revenue									266,235	258,876	282,041
Ready-mix concrete
Revenue from External Customer [Line Items]
Revenue									607,622	584,114	492,302
Ready-mix concrete | Summit Materials, LLC
Revenue from External Customer [Line Items]
Revenue									607,622	584,114	492,302
Asphalt
Revenue from External Customer [Line Items]
Revenue									330,750	301,247	285,653
Asphalt | Summit Materials, LLC
Revenue from External Customer [Line Items]
Revenue									330,750	301,247	285,653
Paving and related services
Revenue from External Customer [Line Items]
Revenue									360,234	379,540	371,763
Paving and related services | Summit Materials, LLC
Revenue from External Customer [Line Items]
Revenue									360,234	379,540	371,763
Other
Revenue from External Customer [Line Items]
Revenue									187,629	203,401	187,433
Other | Summit Materials, LLC
Revenue from External Customer [Line Items]
Revenue									$ 187,629	$ 203,401	$ 187,433

Revenue Recognition - Contract

Revenue Recognition - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Change in Contract with Customer, Asset [Abstract]
Balance—December 29, 2018	$ 18,602
Changes in revenue billed, contract price or cost estimates	(5,558)	$ 8,702	$ 1,825
Other	44
Balance—December 28, 2019	13,088	18,602
Change in Contract with Customer, Liability [Abstract]
Balance—December 29, 2018	11,840
Changes in revenue billed, contract price or cost estimates	1,988	(5,052)	109
Other	36
Balance—December 28, 2019	13,864	11,840
Summit Materials, LLC
Change in Contract with Customer, Asset [Abstract]
Balance—December 29, 2018	18,602
Changes in revenue billed, contract price or cost estimates	(5,558)	8,702	1,825
Other	44
Balance—December 28, 2019	13,088	18,602
Change in Contract with Customer, Liability [Abstract]
Balance—December 29, 2018	11,840
Changes in revenue billed, contract price or cost estimates	1,988	(5,052)	$ 109
Other	36
Balance—December 28, 2019	$ 13,864	$ 11,840

Revenue Recognition - Summary o

Revenue Recognition - Summary of Accounts Receivable, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 191,672	$ 157,601
Construction contract receivables	47,966	47,994
Retention receivables	17,808	15,010
Receivables from related parties	1,596	629
Accounts receivable	259,042	221,234
Less: Allowance for doubtful accounts	(5,786)	(6,716)
Accounts receivable, net	253,256	214,518
Summit Materials, LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	191,672	157,601
Construction contract receivables	47,966	47,994
Retention receivables	17,808	15,010
Receivables from related parties	1,596	629
Accounts receivable	259,042	221,234
Less: Allowance for doubtful accounts	(5,786)	(6,716)
Accounts receivable, net	$ 253,256	$ 214,518
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
General collection and billing period for retention receivables	1 year
Maximum | Summit Materials, LLC
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	Dec. 28, 2019	Dec. 29, 2018
Inventory [Line Items]
Aggregate stockpiles	$ 140,461	$ 151,300
Finished goods	33,023	34,993
Work in process	7,664	7,478
Raw materials	23,639	20,080
Total	204,787	213,851
Summit Materials, LLC
Inventory [Line Items]
Aggregate stockpiles	140,461	151,300
Finished goods	33,023	34,993
Work in process	7,664	7,478
Raw materials	23,639	20,080
Total	$ 204,787	$ 213,851

Property, Plant and Equipment_3

Property, Plant and Equipment, net and Intangibles, net - Components of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment		$ 2,574,383
Property, plant and equipment	$ 2,703,264
Less accumulated depreciation, depletion and amortization	(955,815)
Less accumulated depreciation, depletion and amortization		(794,251)
Property, plant and equipment, net	1,747,449
Property, plant and equipment, net		1,780,132
Depreciation, depletion and amortization expense	196,800	199,600	$ 174,400
Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Property, plant and equipment		2,574,383
Property, plant and equipment	2,703,264
Less accumulated depreciation, depletion and amortization	(955,815)
Less accumulated depreciation, depletion and amortization		(794,251)
Property, plant and equipment, net	1,747,449
Property, plant and equipment, net		1,780,132
Depreciation, depletion and amortization expense	196,800	199,600	$ 174,400
Land (mineral bearing) and asset retirement costs
Property, Plant and Equipment [Line Items]
Property, plant and equipment	333,024	323,553
Land (mineral bearing) and asset retirement costs | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Property, plant and equipment	333,024	323,553
Land (non-mineral bearing)
Property, Plant and Equipment [Line Items]
Property, plant and equipment	182,065	184,029
Land (non-mineral bearing) | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Property, plant and equipment	182,065	184,029
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 178,088	173,559
Buildings and improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Buildings and improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	30 years
Buildings and improvements | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 178,088	173,559
Buildings and improvements | Summit Materials, LLC | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Buildings and improvements | Summit Materials, LLC | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	30 years
Plants, machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment		1,239,793
Property, plant and equipment	$ 1,318,512
Plants, machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Plants, machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Plants, machinery and equipment | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Property, plant and equipment		1,239,793
Property, plant and equipment	$ 1,318,512
Plants, machinery and equipment | Summit Materials, LLC | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Plants, machinery and equipment | Summit Materials, LLC | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Mobile equipment and barges
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 501,809	468,313
Mobile equipment and barges | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	6 years
Mobile equipment and barges | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	8 years
Mobile equipment and barges | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 501,809	468,313
Mobile equipment and barges | Summit Materials, LLC | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	6 years
Mobile equipment and barges | Summit Materials, LLC | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	8 years
Truck and auto fleet
Property, Plant and Equipment [Line Items]
Property, plant and equipment		51,938
Property, plant and equipment	$ 54,838
Truck and auto fleet | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Truck and auto fleet | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	8 years
Truck and auto fleet | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Property, plant and equipment		51,938
Property, plant and equipment	$ 54,838
Truck and auto fleet | Summit Materials, LLC | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Truck and auto fleet | Summit Materials, LLC | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	8 years
Landfill airspace and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 49,766	49,754
Landfill airspace and improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Landfill airspace and improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	30 years
Landfill airspace and improvements | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 49,766	49,754
Landfill airspace and improvements | Summit Materials, LLC | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Landfill airspace and improvements | Summit Materials, LLC | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	30 years
Office equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment		39,794
Property, plant and equipment	$ 43,155
Office equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Office equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
Office equipment | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Property, plant and equipment		39,794
Property, plant and equipment	$ 43,155
Office equipment | Summit Materials, LLC | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Office equipment | Summit Materials, LLC | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 42,007	43,650
Construction in progress | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 42,007	$ 43,650
Other | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	4 years
Other | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Other | Summit Materials, LLC | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	4 years
Other | Summit Materials, LLC | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years

Property, Plant and Equipment_4

Property, Plant and Equipment, net and Intangibles, net - Capital and Finance Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Property, Plant and Equipment [Line Items]
Finance lease ROU assets included in property, plant and equipment, gross	$ 82,660
Property, plant and equipment		$ 1,780,132
Finance lease, ROU asset, accumulated amortization	24,907
Property, plant and equipment, accumulated depreciation, depletion and amortization		794,251
Current finance lease liabilities	16,007
Capital lease obligations, current		15,557
Long-term finance lease liabilities	40,410
2020	18,646
2021	21,886
2022	14,940
2023	1,732
2024	2,252
General and administrative expenses
Property, Plant and Equipment [Line Items]
Net gain from asset dispositions	10,700	12,600	$ 7,500
Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Finance lease ROU assets included in property, plant and equipment, gross	82,660
Property, plant and equipment		1,780,132
Finance lease, ROU asset, accumulated amortization	24,907
Property, plant and equipment, accumulated depreciation, depletion and amortization		794,251
Current finance lease liabilities	16,007
Capital lease obligations, current		15,557
Long-term finance lease liabilities	40,410
2020	18,646
2021	21,886
2022	14,940
2023	1,732
2024	2,252
Summit Materials, LLC | General and administrative expenses
Property, Plant and Equipment [Line Items]
Net gain from asset dispositions	$ 10,700	12,600	$ 7,500
Capital leases for equipment and building
Property, Plant and Equipment [Line Items]
Property, plant and equipment		67,700
Property, plant and equipment, accumulated depreciation, depletion and amortization		19,300
Capital leases for equipment and building | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Property, plant and equipment		67,700
Property, plant and equipment, accumulated depreciation, depletion and amortization		19,300
Equipment
Property, Plant and Equipment [Line Items]
Equipment lease term	5 years
Equipment | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Equipment lease term	5 years
Building
Property, Plant and Equipment [Line Items]
Equipment lease term	30 years
Building | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Equipment lease term	30 years
Accrued expenses
Property, Plant and Equipment [Line Items]
Capital lease obligations, current		15,600
Accrued expenses | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Capital lease obligations, current	$ 16,000	15,600
Noncurrent liabilities
Property, Plant and Equipment [Line Items]
Capital lease obligations, noncurrent		33,600
Noncurrent liabilities | Summit Materials, LLC
Property, Plant and Equipment [Line Items]
Long-term finance lease liabilities	$ 40,400
Capital lease obligations, noncurrent		$ 33,600

Property, Plant and Equipment_5

Property, Plant and Equipment, net and Intangibles, net - Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 33,864	$ 26,707
Accumulated Amortization	(10,366)	(8,247)
Net Carrying Amount	23,498	18,460
Amortization expense	2,100	1,500	$ 1,300
Estimated amortization expense
2020	2,526
2021	2,138
2022	2,142
2023	2,009
2024	1,914
Thereafter	12,769
Total	23,498	18,460
Summit Materials, LLC
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	33,864	26,707
Accumulated Amortization	(10,366)	(8,247)
Net Carrying Amount	23,498	18,460
Amortization expense	2,100	1,500	$ 1,300
Estimated amortization expense
2020	2,526
2021	2,138
2022	2,142
2023	2,009
2024	1,914
Thereafter	12,769
Total	23,498	18,460
Mineral leases
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	19,064	19,064
Accumulated Amortization	(6,408)	(5,259)
Net Carrying Amount	12,656	13,805
Mineral leases | Summit Materials, LLC
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	19,064	19,064
Accumulated Amortization	(6,408)	(5,259)
Net Carrying Amount	12,656	13,805
Reserve rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6,234	6,234
Accumulated Amortization	(2,248)	(1,940)
Net Carrying Amount	3,986	4,294
Reserve rights | Summit Materials, LLC
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6,234	6,234
Accumulated Amortization	(2,248)	(1,940)
Net Carrying Amount	3,986	4,294
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,000	1,000
Accumulated Amortization	(958)	(858)
Net Carrying Amount	42	142
Trade names | Summit Materials, LLC
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,000	1,000
Accumulated Amortization	(958)	(858)
Net Carrying Amount	42	142
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,566	409
Accumulated Amortization	(752)	(190)
Net Carrying Amount	6,814	219
Other | Summit Materials, LLC
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,566	409
Accumulated Amortization	(752)	(190)
Net Carrying Amount	$ 6,814	$ 219

Accrued Expenses - Components o

Accrued Expenses - Components of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Schedule Of Accrued Expenses [Line Items]
Interest	$ 26,892	$ 26,223
Payroll and benefits	29,356	15,952
Finance lease obligations	16,007
Finance lease obligations		15,557
Insurance	14,968	13,625
Non-income taxes	7,666	7,442
Professional fees	902	1,408
Other	24,214	20,284
Total	120,005	100,491
Summit Materials, LLC
Schedule Of Accrued Expenses [Line Items]
Interest	26,892	26,223
Payroll and benefits	29,356	15,952
Finance lease obligations	16,007
Finance lease obligations		15,557
Insurance	14,968	13,625
Non-income taxes	7,898	7,674
Professional fees	902	1,408
Other	24,214	19,590
Total	$ 120,237	$ 100,029

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Mar. 30, 2019	Dec. 29, 2018	Jun. 01, 2017
Debt
Total debt	$ 1,872,273		$ 1,828,159
Current portion of long-term debt	7,942		6,354
Long-term debt	1,864,331		1,821,805
Gross amount	1,874,255
Debt discount	1,982
Summit Materials, LLC
Debt
Total debt	1,872,273		1,828,159
Current portion of long-term debt	7,942		6,354
Long-term debt	1,864,331		1,821,805
Gross amount	1,874,255
Debt discount	1,982
Term Loan, due 2024
Debt
Total debt	623,140		629,268
Gross amount	624,300		630,600
Debt discount	1,100		1,300
Term Loan, due 2024 | Summit Materials, LLC
Debt
Total debt	623,140		629,268
Gross amount	624,300		630,600
Debt discount	1,100		1,300
8 1/2% Senior Notes, due 2022
Debt
Total debt	0		$ 250,000
Debt instrument interest rate (as a percent)			8.50%
8 1/2% Senior Notes, due 2022 | Summit Materials, LLC
Debt
Total debt	0		$ 250,000
Debt instrument interest rate (as a percent)		8.50%	8.50%
6 1/8% Senior Notes, due 2023
Debt
Total debt	649,133		$ 648,891
Gross amount	650,000		650,000
Debt discount	$ 900		1,100
Debt instrument interest rate (as a percent)	6.125%
6 1/8% Senior Notes, due 2023 | Summit Materials, LLC
Debt
Total debt	$ 649,133		648,891
Gross amount	650,000		650,000
Debt discount	$ 900		1,100
Debt instrument interest rate (as a percent)	6.125%
5 1/8% Senior Notes, due 2025
Debt
Total debt	$ 300,000		300,000
5 1/8% Senior Notes, due 2025 | Summit Materials, LLC
Debt
Total debt	$ 300,000		300,000	$ 300,000
Debt instrument interest rate (as a percent)	5.125%			5.125%
Senior Notes | 6 1⁄2% Senior Notes, due 2027
Debt
Total debt	$ 300,000		0
Debt instrument interest rate (as a percent)	6.50%
Senior Notes | 6 1⁄2% Senior Notes, due 2027 | Summit Materials, LLC
Debt
Total debt	$ 300,000		$ 0
Debt instrument interest rate (as a percent)	6.50%

Debt - Schedule of Contractual

Debt - Schedule of Contractual Payments of Long-Term Debt (Details) $ in Thousands	Dec. 28, 2019USD ($)
Contractual payments of long-term debt
2020	$ 7,942
2021	6,354
2022	6,354
2023	656,354
2024	597,251
Thereafter	600,000
Total	1,874,255
Less: Original issue net discount	(1,982)
Less: Capitalized loan costs	(13,274)
Total debt	1,858,999
Summit Materials, LLC
Contractual payments of long-term debt
2020	7,942
2021	6,354
2022	6,354
2023	656,354
2024	597,251
Thereafter	600,000
Total	1,874,255
Less: Original issue net discount	(1,982)
Less: Capitalized loan costs	(13,274)
Total debt	$ 1,858,999

Debt - Senior Notes (Details)

Debt - Senior Notes (Details) - USD ($)	Mar. 15, 2019	Jun. 01, 2017	Mar. 30, 2019	Dec. 28, 2019	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016	Dec. 29, 2018	Nov. 30, 2015	Aug. 31, 2015	Apr. 30, 2015	Mar. 31, 2015
Debt
Long-term debt				$ 1,872,273,000				$ 1,828,159,000
Write off of deferred financing fees				2,850,000
8 1/2% Senior Notes, due 2022
Debt
Long-term debt				0				$ 250,000,000
Senior notes, interest rate (as a percent)								8.50%
5 1/8% Senior Notes, due 2025
Debt
Long-term debt				300,000,000				$ 300,000,000
6 1/8% Senior Notes, due 2023
Debt
Long-term debt				$ 649,133,000				648,891,000
Senior notes, interest rate (as a percent)				6.125%
10 1/2% Senior Notes, due 2020
Debt
Senior notes, interest rate (as a percent)												10.50%
Senior notes, aggregate principal amount redeemed									$ 153,800,000	$ 183,000,000	$ 288,200,000
Prepayment premium					$ 66,600,000
Write off of deferred financing fees					11,900,000
Charges on redemption						$ 56,500,000
Net benefit from the write-off the original issuance premium and discount					$ 22,000,000
Issuers | 8 1/2% Senior Notes, due 2022
Debt
Senior notes, interest rate (as a percent)			8.50%
Loss on extinguishment of debt			$ (14,600,000)
Senior notes, aggregate principal amount redeemed			250,000,000
Prepayment premium			11,700,000
Write off of deferred financing fees			$ 2,900,000
Issuers | 5 1/8% Senior Notes, due 2025
Debt
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
Debt
Senior notes, interest rate (as a percent)							6.125%
Debt instrument, face amount							$ 650,000,000
Issuers | 6 1/8% Senior Notes, due 2023, issued at par
Debt
Debt instrument, face amount							$ 350,000,000
Issuers | 6 1/8% Senior Notes, due 2023, , issued at 99.375% of par
Debt
Percentage of par value of senior notes							99.375%
Debt instrument, face amount							$ 300,000,000
Summit Materials, LLC
Debt
Long-term debt				$ 1,872,273,000				1,828,159,000
Write off of deferred financing fees				2,850,000
Summit Materials, LLC | 8 1/2% Senior Notes, due 2022
Debt
Long-term debt				0				$ 250,000,000
Senior notes, interest rate (as a percent)			8.50%					8.50%
Loss on extinguishment of debt			$ (14,600,000)
Senior notes, aggregate principal amount redeemed			250,000,000
Prepayment premium			11,700,000
Write off of deferred financing fees			$ 2,900,000
Summit Materials, LLC | 5 1/8% Senior Notes, due 2025
Debt
Long-term debt		$ 300,000,000		$ 300,000,000				$ 300,000,000
Senior notes, interest rate (as a percent)		5.125%		5.125%
Percentage of par value of senior notes		100.00%
Proceeds net of related fees and expenses		$ 295,400,000
Summit Materials, LLC | 6 1/8% Senior Notes, due 2023
Debt
Long-term debt				$ 649,133,000				648,891,000
Senior notes, interest rate (as a percent)				6.125%
Summit Materials, LLC | 10 1/2% Senior Notes, due 2020
Debt
Senior notes, interest rate (as a percent)												10.50%
Senior notes, aggregate principal amount redeemed									$ 153,800,000	$ 183,000,000	$ 288,200,000
Prepayment premium						66,600,000
Write off of deferred financing fees						11,900,000
Charges on redemption						56,500,000
Net benefit from the write-off the original issuance premium and discount						$ 22,000,000
Senior Notes | 6 1⁄2% Senior Notes, due 2027
Debt
Long-term debt				$ 300,000,000				0
Senior notes, interest rate (as a percent)				6.50%
Senior Notes | Issuers | 6 1⁄2% Senior Notes, due 2027
Debt
Long-term debt	$ 300,000,000
Senior notes, interest rate (as a percent)	6.50%
Percentage of par value of senior notes	100.00%
Proceeds net of related fees and expenses	$ 296,300,000
Senior Notes | Summit Materials, LLC | 6 1⁄2% Senior Notes, due 2027
Debt
Long-term debt				$ 300,000,000				$ 0
Senior notes, interest rate (as a percent)				6.50%

Debt - Senior Secured Credit Fa

Debt - Senior Secured Credit Facilities (Details) - USD ($)	Feb. 25, 2019	May 22, 2018	Dec. 28, 2019	Dec. 29, 2018
Debt
Outstanding principal amount			$ 1,874,255,000
Term Loan, due 2024
Debt
Outstanding principal amount			624,300,000	$ 630,600,000
Summit Materials, LLC
Debt
Outstanding principal amount			1,874,255,000
Summit Materials, LLC | Term Loan, due 2024
Debt
Debt instrument, face amount			650,000,000
Outstanding principal amount			624,300,000	630,600,000
Summit Materials, LLC | Revolving Credit Facility
Debt
Maximum borrowing capacity	$ 345,000,000		$ 345,000,000
Basis spread on variable rate			0.25%
Amount outstanding			$ 0	$ 0
Remaining borrowing capacity			329,800,000
Summit Materials, LLC | Revolving Credit Facility | Federal funds rate
Debt
Basis spread on variable rate	0.50%	0.50%
Summit Materials, LLC | Revolving Credit Facility | LIBOR Plus 1%
Debt
Basis spread on variable rate	2.00%	2.00%
Percentage added to base rate	1.00%	1.00%
Summit Materials, LLC | Revolving Credit Facility | LIBOR
Debt
Basis spread on variable rate	3.00%	3.00%
Summit Materials, LLC | Letter of Credit
Debt
Amount outstanding			$ 15,200,000
Summit Materials, LLC | Senior Secured Credit Facilities
Debt
First lien leverage ratio			4.75

Debt - Summary of Activity for

Debt - Summary of Activity for Deferred Financing Fees (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Deferred finance costs
Beginning balance	$ 15,475	$ 19,033
Loan origination fees	6,312	550
Amortization	(3,501)	(4,108)
Write off of deferred financing fees	(2,850)
Ending balance	15,436	15,475
Summit Materials, LLC
Deferred finance costs
Beginning balance	15,475	19,033
Loan origination fees	6,312	550
Amortization	(3,501)	(4,108)
Write off of deferred financing fees	(2,850)
Ending balance	$ 15,436	$ 15,475

Debt - Other Narrative (Details

Debt - Other Narrative (Details)	Jan. 15, 2015USD ($)	Dec. 28, 2019USD ($)	Dec. 29, 2018USD ($)	Jan. 15, 2015CAD ($)
Canadian subsidiary credit agreement, Operating activities
Debt
Revolving credit commitment				$ 6,000,000
Canadian subsidiary credit agreement, Operating activities | Summit Materials, LLC
Debt
Revolving credit commitment	$ 6,000,000
Canadian subsidiary credit agreement, Capital equipment
Debt
Revolving credit commitment				500,000
Canadian subsidiary credit agreement, Capital equipment | Summit Materials, LLC
Debt
Revolving credit commitment	500,000
Canadian subsidiary credit agreement, Guarantees
Debt
Revolving credit commitment				$ 400,000
Canadian subsidiary credit agreement, Guarantees | Summit Materials, LLC
Debt
Revolving credit commitment	$ 400,000
Canadian subsidiary credit agreement
Debt
Amount outstanding		$ 0	$ 0
Canadian subsidiary credit agreement | Summit Materials, LLC
Debt
Amount outstanding		$ 0	$ 0
Prime rate | Canadian subsidiary credit agreement, Operating activities
Debt
Basis spread on variable rate	0.20%
Prime rate | Canadian subsidiary credit agreement, Operating activities | Summit Materials, LLC
Debt
Basis spread on variable rate	0.20%
Prime rate | Canadian subsidiary credit agreement, Capital equipment
Debt
Basis spread on variable rate	0.90%
Prime rate | Canadian subsidiary credit agreement, Capital equipment | Summit Materials, LLC
Debt
Basis spread on variable rate	0.90%

Income Taxes - Components of In

Income Taxes - Components of Income Tax Benefit (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Provision for income taxes:
Current	$ 69	$ 463	$ 2,530
Deferred	17,032	59,284	(286,507)
Income tax expense (benefit)	17,101	59,747	(283,977)
Summit Materials, LLC
Provision for income taxes:
Current	69	463	2,762
Deferred	6,316	9,810	(23,107)
Income tax expense (benefit)	$ 6,385	$ 10,273	$ (20,345)

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Tax Benefit (Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Effective Income Tax Rate Continuing Operations Tax Rate Reconciliation [Line Items]
Income tax expense (benefit) at federal statutory tax rate	$ 16,427	$ 20,177	$ (55,365)
Less: Income tax benefit at federal statutory tax rate for LLC entities	(658)	(561)	(2,123)
State and local income taxes	3,792	4,894	(5,209)
Permanent differences	(6,272)	(5,537)	(4,410)
Effective tax rate change	(2,006)	4,034	216,904
Unrecognized tax benefits	18,885	22,663	0
Tax receivable agreement (benefit) expense	2,436	(8,282)	104,804
Change in valuation allowance	(17,691)	17,592	(500,162)
Impact of LP Unit ownership change	0	0	(31,790)
Other	2,188	4,767	(6,626)
Income tax expense (benefit)	17,101	59,747	(283,977)
Summit Materials, LLC
Effective Income Tax Rate Continuing Operations Tax Rate Reconciliation [Line Items]
Income tax expense (benefit) at federal statutory tax rate	19,947	15,563	39,797
Less: Income tax benefit at federal statutory tax rate for LLC entities	(15,387)	(13,863)	(36,171)
State and local income taxes	1,680	1,614	1,751
Permanent differences	13	(1,194)	(630)
Effective tax rate change	(725)	(1,148)	(24,243)
Unrecognized tax benefits	5,038	6,487	0
Change in valuation allowance	(2,478)	2,586	0
Other	(1,703)	228	(849)
Income tax expense (benefit)	$ 6,385	$ 10,273	$ (20,345)

Income Taxes - Components of Ne

Income Taxes - Components of Net Deferred Income Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Deferred tax assets (liabilities):
Net intangible assets	$ 240,790	$ 275,412
Accelerated depreciation	(201,126)	(185,020)
Net operating loss	164,335	143,234
Investment in limited partnership	(31,987)	(29,981)
Mining reclamation reserve	2,018	1,600
Working capital (e.g., accrued compensation, prepaid assets)	37,287	36,932
Interest expense limitation carryforward	2,691	2,586
Less valuation allowance	(1,675)	(19,366)	$ (1,675)
Deferred tax assets	212,333	225,397
Less foreign deferred tax liability (included in other noncurrent liabilities)	(8,267)	(5,133)
Net deferred tax asset	204,066	220,264
Summit Materials, LLC
Deferred tax assets (liabilities):
Accelerated depreciation	(60,216)	(57,437)
Net operating loss	18,036	22,915
Investment in limited partnership	(17,686)	(16,591)
Net intangible assets	(2,554)	(1,734)
Mining reclamation reserve	723	570
Working capital (e.g., accrued compensation, prepaid assets)	1,366	1,059
Interest expense limitation carryforward	2,691	2,586
Less valuation allowance	(1,675)	(4,261)	$ (1,675)
Deferred tax liabilities, net	(57,640)	(48,632)
Net deferred tax liability, net	$ (59,315)	$ (52,893)

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 29, 2018	Dec. 30, 2017	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017	Sep. 30, 2017
Income Taxes [Line Items]
Unrecognized tax benefits			$ 18,885,000	$ 22,663,000	$ 0
Deferred tax assets subject to TRA			384,700,000
Income tax expense (benefit)			17,101,000	59,747,000	(283,977,000)
Reduction of net deferred tax assets due to change in statutory rate	$ 17,600,000	$ 216,900,000
Unrecognized tax benefits	22,663,000	0	41,548,000	22,663,000	0
Unrecognized tax benefits that if recognized would affect the annual effective tax rate	22,700,000		41,500,000	22,700,000
Alternative minimum tax credit			200,000
Deferred tax asset, valuation allowance	19,366,000	1,675,000	1,675,000	19,366,000	1,675,000
Deferred tax asset, Investment in limited partnership	2,000,000		1,100,000	2,000,000
Tax receivable agreement expense (benefit)			16,237,000	(22,684,000)	271,016,000
Tax receivable agreement liability	309,674,000		326,965,000	309,674,000
Penalties and interest expense			0	0	0
Liability for uncertainty in income taxes		0			0
Summit Holdings LP
Income Taxes [Line Items]
Distributions to LP Unitholders			100,000	100,000
Summit Materials, LLC
Income Taxes [Line Items]
Unrecognized tax benefits			5,038,000	6,487,000	0
Income tax expense (benefit)			6,385,000	10,273,000	(20,345,000)
Reduction of net deferred tax assets due to change in statutory rate	2,600,000
Unrecognized tax benefits	6,487,000	0	11,619,000	6,487,000	0
Net operating loss carryforwards			120,300,000
Deferred tax asset, valuation allowance	4,261,000	$ 1,675,000	$ 1,675,000	4,261,000	$ 1,675,000
Penalties and interest expense				0
Tax Receivable Agreement
Income Taxes [Line Items]
Tax benefit deemed probable						$ 501,800,000
Tax Receivable Agreement | Summit Holdings LP
Income Taxes [Line Items]
Percentage of benefits to be paid on tax receivable agreement			85.00%		85.00%
Other noncurrent liabilities | Tax Receivable Agreement
Income Taxes [Line Items]
Tax receivable agreement liability	309,700,000			309,700,000
Accrued expenses. | Tax Receivable Agreement
Income Taxes [Line Items]
Tax receivable agreement liability	$ 700,000		$ 0	$ 700,000
Federal
Income Taxes [Line Items]
Net operating loss carryforwards			822,000,000
Federal | Tax Receivable Agreement
Income Taxes [Line Items]
Net operating loss carryforwards			$ 411,000,000

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance—December 29, 2018	$ 22,663	$ 0
Additions based on tax position in 2019	18,885	22,663
Balance—December 28, 2019	41,548	22,663
Summit Materials, LLC
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance—December 29, 2018	6,487	0
Additions based on tax position in 2019	5,132	6,487
Balance—December 28, 2019	$ 11,619	$ 6,487

Incomes Taxes - Deferred Tax As

Incomes Taxes - Deferred Tax Asset Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Valuation Allowance:
Beginning balance	$ (19,366)	$ (1,675)
Additional basis from exchanged LP Units	0	(99)
Current year decreases (increases) from operations	17,691	(17,592)
Ending balance	(1,675)	(19,366)
Summit Materials, LLC
Valuation Allowance:
Beginning balance	(4,261)	(1,675)
Current year decreases (increases) from operations	2,586	(2,586)
Ending balance	$ (1,675)	$ (4,261)

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								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Reconciliation of basic to diluted loss per share
Net income attributable to Summit Inc.	$ 35,671	$ 55,757	$ 36,410	$ (68,772)	$ (19,163)	$ 71,289	$ 35,509	$ (53,729)	$ 59,066	$ 33,906	$ 121,830
Basic (USD per share)	$ 0.32	$ 0.50	$ 0.32	$ (0.62)	$ (0.17)	$ 0.64	$ 0.32	$ (0.49)
Diluted net income attributable to Summit Inc.									$ 59,066	$ 33,906	$ 121,830
Diluted (USD per share)	$ 0.31	$ 0.48	$ 0.32	$ (0.62)	$ (0.17)	$ 0.64	$ 0.32	$ (0.49)
LP Units
Reconciliation of basic to diluted loss per share
Anti dilutive shares excluded from calculation of earnings per share									3,372,706	3,512,669	4,371,705
Common Class A
Reconciliation of basic to diluted loss per share
Weighted average shares of Class A stock outstanding (in shares)									112,204,067	111,380,175	108,696,438
Basic (USD per share)									$ 0.53	$ 0.30	$ 1.12
Add: warrants									4,206	25,049	42,035
Weighted average dilutive shares outstanding (in shares)									112,684,718	112,316,646	109,490,898
Diluted (USD per share)									$ 0.52	$ 0.30	$ 1.11
Common Class A | Options
Reconciliation of basic to diluted loss per share
Add: Share-based payment arrangements									87,290	282,329	308,355
Common Class A | Restricted stock
Reconciliation of basic to diluted loss per share
Add: Share-based payment arrangements									342,620	459,280	308,221
Common Class A | Performance Stock Units
Reconciliation of basic to diluted loss per share
Add: Share-based payment arrangements									46,535	169,813	135,849

Stockholders' Equity_Members' I

Stockholders' Equity/Members' Interest - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 10, 2017	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Subsidiary, Sale of Stock [Line Items]
Common stock, shares authorized (in shares)		1,000,000,000
Proceeds from sale of common stock, net of underwriting discounts		$ 0	$ 0	$ 237,600
Common Class A
Subsidiary, Sale of Stock [Line Items]
Common stock, shares authorized (in shares)		1,000,000,000	1,000,000,000
Common stock, par value (USD per share)		$ 0.01	$ 0.01
Common stock, shares issued (in shares)		113,309,385	111,658,927	110,350,594
Common stock, shares outstanding (in shares)		113,309,385	111,658,927
Common Class A | Follow on Public Offering
Subsidiary, Sale of Stock [Line Items]
Proceeds from sale of common stock, net of underwriting discounts	$ 237,600
Common stock issued (in shares)	10,000,000
Offering price (in dollars per share)	$ 24.05
Common Class B
Subsidiary, Sale of Stock [Line Items]
Common stock, shares authorized (in shares)		250,000,000	250,000,000
Common stock, par value (USD per share)		$ 0.01	$ 0.01
Common stock, shares issued (in shares)		99	99
Common stock, shares outstanding (in shares)		99	99

Stockholders' Equity_Members'_2

Stockholders' Equity/Members' Interest - Change in Ownership (Details) - shares	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Increase (Decrease) In Stockholders' Equity [Rollforward]
Stock option exercises (in shares)	1,065,446	863,898
Summit Materials Incorporated And Summit Holdings LP
Increase (Decrease) In Stockholders' Equity [Rollforward]
Beginning balance stockholders' equity (in shares)	115,094,445	114,040,214
Exchanges during period (in shares)	0	0
Other equity transactions (in shares)	399,151	190,333
Ending balance stockholders' equity (in shares)	116,559,042	115,094,445	114,040,214
LP Units | Summit Holdings LP
Increase (Decrease) In Stockholders' Equity [Rollforward]
Number of LP Units outstanding (in shares)	3,435,518	3,689,620
Number of LP Units exchanged	(185,861)	(254,102)
Number of LP Units outstanding (in shares)	3,249,657	3,435,518	3,689,620
Common Class A
Increase (Decrease) In Stockholders' Equity [Rollforward]
Beginning balance stockholders' equity (in shares)	111,658,927	110,350,594
Exchanges during period (in shares)	185,861	254,102
Stock option exercises (in shares)	1,065,446	863,898
Other equity transactions (in shares)	399,151	190,333
Ending balance stockholders' equity (in shares)	113,309,385	111,658,927	110,350,594
Summit Materials Inc
Increase (Decrease) In Stockholders' Equity [Rollforward]
Summit Inc. Ownership Percentage	97.20%	97.00%	96.80%

Stockholders' Equity_Members'_3

Stockholders' Equity/Members' Interest - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Changes in each component of accumulated other comprehensive loss
Beginning balance stockholders' equity	$ 1,342,145	$ 1,271,721
Postretirement liability adjustment, net of tax	(1,402)	1,209
Foreign currency translation adjustment, net of tax	3,424	(6,784)
Income on cash flow hedges, net of tax		870
Income on cash flow hedges, net of tax	(1,255)
Ending balance stockholders' equity	1,444,773	1,342,145
Change in retirement plans
Changes in each component of accumulated other comprehensive loss
Beginning balance stockholders' equity	3,573	2,364
Postretirement liability adjustment, net of tax	(1,402)	1,209
Ending balance stockholders' equity	2,171	3,573
Foreign currency translation adjustment
Changes in each component of accumulated other comprehensive loss
Beginning balance stockholders' equity	(2,147)	4,637
Foreign currency translation adjustment, net of tax	3,424	(6,784)
Ending balance stockholders' equity	1,277	(2,147)
Cash flow hedge adjustments
Changes in each component of accumulated other comprehensive loss
Beginning balance stockholders' equity	1,255	385
Income on cash flow hedges, net of tax		870
Ending balance stockholders' equity		1,255
Cash flow hedge adjustments
Changes in each component of accumulated other comprehensive loss
Income on cash flow hedges, net of tax	(1,255)
Ending balance stockholders' equity	0
Accumulated Other Comprehensive Income (Loss)
Changes in each component of accumulated other comprehensive loss
Beginning balance stockholders' equity	2,681	7,386
Ending balance stockholders' equity	3,448	2,681
Summit Materials, LLC
Changes in each component of accumulated other comprehensive loss
Postretirement liability adjustment, net of tax	(1,925)	1,661
Foreign currency translation adjustment, net of tax	4,716	(9,348)
Income on cash flow hedges, net of tax		1,206
Income on cash flow hedges, net of tax	(146)
Summit Materials, LLC | Change in retirement plans
Changes in each component of accumulated other comprehensive loss
Beginning balance stockholders' equity	(4,392)	(6,053)
Postretirement liability adjustment, net of tax	(1,925)	1,661
Ending balance stockholders' equity	(6,317)	(4,392)
Summit Materials, LLC | Foreign currency translation adjustment
Changes in each component of accumulated other comprehensive loss
Beginning balance stockholders' equity	(19,370)	(10,022)
Foreign currency translation adjustment, net of tax	4,716	(9,348)
Ending balance stockholders' equity	(14,654)	(19,370)
Summit Materials, LLC | Cash flow hedge adjustments
Changes in each component of accumulated other comprehensive loss
Beginning balance stockholders' equity	146	(1,060)
Income on cash flow hedges, net of tax		1,206
Ending balance stockholders' equity		146
Summit Materials, LLC | Cash flow hedge adjustments
Changes in each component of accumulated other comprehensive loss
Income on cash flow hedges, net of tax	(146)
Ending balance stockholders' equity	0
Summit Materials, LLC | Accumulated Other Comprehensive Income (Loss)
Changes in each component of accumulated other comprehensive loss
Beginning balance stockholders' equity	(23,616)	(17,135)
Ending balance stockholders' equity	$ (20,971)	$ (23,616)

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information - Schedule of Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Cash payments:
Interest	$ 104,614	$ 103,250	$ 96,320
(Refund) payments for income taxes, net	(919)	3,340	1,711
Operating cash payments on operating leases	10,618
Operating cash payments on finance leases	3,051
Finance cash payments on finance leases	13,164
Non cash financing activities:
Purchase of noncontrolling interest	0	0	(716)
Stock Dividend	0	0	(45,023)
Right of use assets obtained in exchange for operating lease obligations	5,842
Right of use assets obtained in exchange for finance leases obligations	23,965
Exchange of LP Units to shares of Class A common stock	3,847	7,499	41,126
Summit Materials, LLC
Cash payments:
Interest	104,614	103,250	96,320
(Refund) payments for income taxes, net	(919)	3,340	1,711
Operating cash payments on operating leases	10,618
Operating cash payments on finance leases	3,051
Finance cash payments on finance leases	13,164
Non cash financing activities:
Purchase of noncontrolling interest	0	$ 0	$ (716)
Right of use assets obtained in exchange for operating lease obligations	5,842
Right of use assets obtained in exchange for finance leases obligations	$ 23,965

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017	Jan. 02, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		$ 20,400,000	$ 25,400,000	$ 49,900,000
Unrecognized compensation cost		$ 26,300,000
Weighted average contractual term, unrecognized compensation cost		1 year 9 months 18 days
2015 Omnibus Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)					13,500,000
Shares available for grant (in shares)		5,600,000
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted during the period (in shares)		1,238,530
Intrinsic value, options outstanding		$ 37,100,000
Weighted average remaining contractual term		1 year
Restricted stock | 2015 Omnibus Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted during the period (in shares)		65,144	38,232	34,928
Award vesting period		1 year
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, granted (in shares)		0	0
Intrinsic value, units outstanding		$ 10,700,000
Weighted average remaining contractual term		5 years 6 months
Weighted average strike price, outstanding (in dollars per share)		$ 18.81
Exercisable (in shares)		2,000,000
Intrinsic value, exercisable stock options		$ 10,700,000
Weighted average strike price, exercisable (in dollars per share)		$ 18.54
Weighed average remaining contractual term, exercisable		5 years 6 months
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted during the period (in shares)		242,007
Award vesting period			3 years
Intrinsic value, units outstanding		$ 9,300,000
Weighted average remaining contractual term		1 year 6 months
Summit Materials, LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense		$ 20,400,000	$ 25,400,000	$ 49,900,000
Unrecognized compensation cost		$ 26,300,000
Weighted average contractual term, unrecognized compensation cost		1 year 9 months 18 days
Weighed average remaining contractual term, exercisable		5 years 6 months
Summit Materials, LLC | Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted during the period (in shares)		1,238,530
Intrinsic value, options outstanding		$ 0
Intrinsic value, units outstanding		$ 37,100,000
Weighted average remaining contractual term		1 year
Summit Materials, LLC | Restricted stock | 2015 Omnibus Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		1 year
Summit Materials, LLC | Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, granted (in shares)		0	0
Intrinsic value, options outstanding		$ 10,700,000
Weighted average remaining contractual term		5 years 6 months
Weighted average strike price, outstanding (in dollars per share)		$ 18.81
Exercisable (in shares)		2,000,000
Intrinsic value, exercisable stock options		$ 10,700,000
Weighted average strike price, exercisable (in dollars per share)		$ 18.54
Summit Materials, LLC | Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted during the period (in shares)		242,007
Award vesting period		3 years
Intrinsic value, options outstanding		$ 0
Intrinsic value, units outstanding		$ 9,300,000
Weighted average remaining contractual term		1 year 6 months
Summit Holdings LP | Leverage restoration options, time-vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 1,000,000
Minimum | Restricted stock | 2015 Omnibus Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			2 years
Minimum | Summit Materials, LLC | Restricted stock | 2015 Omnibus Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			2 years
Maximum | Restricted stock | 2015 Omnibus Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			3 years
Maximum | Summit Materials, LLC | Restricted stock | 2015 Omnibus Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			3 years

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Award Activity (Details) - $ / shares	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, Exercised (in shares)	(1,065,446)	(863,898)
Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, Beginning balance (in shares)	3,267,149
Options, Granted (in shares)	0	0
Options, Forfeited/Canceled (in shares)	(73,596)
Options, Exercised (in shares)	(1,065,446)
Options, Vested	0
Options, Ending balance (in shares)	2,128,107	3,267,149
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Options, Beginning balance (in dollars per share)	$ 9.09
Options, Granted (in dollars per share)	0
Options, Forfeited/Canceled (in dollars per share)	10.62
Options, Exercised (in dollars per share)	8.93
Options, Vested (in dollars per share)	0
Options, Ending balance (in dollars per share)	$ 9.08	$ 9.09
Options | Summit Materials, LLC
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, Beginning balance (in shares)	3,267,149
Options, Granted (in shares)	0	0
Options, Forfeited/Canceled (in shares)	(73,596)
Options, Exercised (in shares)	(1,065,446)
Options, Vested	0
Options, Ending balance (in shares)	2,128,107	3,267,149
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Options, Beginning balance (in dollars per share)	$ 9.09
Options, Granted (in dollars per share)	0
Options, Forfeited/Canceled (in dollars per share)	10.62
Options, Exercised (in dollars per share)	8.93
Options, Vested (in dollars per share)	0
Options, Ending balance (in dollars per share)	$ 9.08	$ 9.09
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of units, Beginning balance (in shares)	924,308
Number of units, granted (in shares)	1,238,530
Number of units, Forfeited/Canceled (in shares)	(176,152)
Number of units, Exercised (in shares)	0
Number of units, Vested (in shares)	(430,050)
Number of units, Ending balance (in shares)	1,556,636	924,308
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Number of units, Beginning balance (in dollars per share)	$ 24.57
Number of units, Granted (in dollars per share)	17.60
Number of units, Forfeited/Canceled (in dollars per share)	22.21
Number of units, Exercised (in dollars per share)	0
Number of units, Vested (in dollars per share)	23.71
Number of units, Ending balance (in dollars per share)	$ 21.17	$ 24.57
Restricted stock | Summit Materials, LLC
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of units, Beginning balance (in shares)	924,308
Number of units, granted (in shares)	1,238,530
Number of units, Forfeited/Canceled (in shares)	(176,152)
Number of units, Exercised (in shares)	0
Number of units, Vested (in shares)	(430,050)
Number of units, Ending balance (in shares)	1,556,636	924,308
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Number of units, Beginning balance (in dollars per share)	$ 24.57
Number of units, Granted (in dollars per share)	17.60
Number of units, Forfeited/Canceled (in dollars per share)	22.21
Number of units, Exercised (in dollars per share)	0
Number of units, Vested (in dollars per share)	23.71
Number of units, Ending balance (in dollars per share)	$ 21.17	$ 24.57
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of units, Beginning balance (in shares)	295,252
Number of units, granted (in shares)	242,007
Number of units, Forfeited/Canceled (in shares)	(146,614)
Number of units, Exercised (in shares)	0
Number of units, Vested (in shares)	0
Number of units, Ending balance (in shares)	390,645	295,252
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Number of units, Beginning balance (in dollars per share)	$ 29.12
Number of units, Granted (in dollars per share)	26.20
Number of units, Forfeited/Canceled (in dollars per share)	20.17
Number of units, Exercised (in dollars per share)	0
Number of units, Vested (in dollars per share)	0
Number of units, Ending balance (in dollars per share)	$ 26.17	$ 29.12
Performance Stock Units | Summit Materials, LLC
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of units, Beginning balance (in shares)	295,252
Number of units, granted (in shares)	242,007
Number of units, Forfeited/Canceled (in shares)	(146,614)
Number of units, Exercised (in shares)	0
Number of units, Vested (in shares)	0
Number of units, Ending balance (in shares)	390,645	295,252
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Number of units, Beginning balance (in dollars per share)	$ 29.12
Number of units, Granted (in dollars per share)	26.20
Number of units, Forfeited/Canceled (in dollars per share)	20.17
Number of units, Exercised (in dollars per share)	0
Number of units, Vested (in dollars per share)	0
Number of units, Ending balance (in dollars per share)	$ 26.17	$ 29.12
Warrants
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of units, Beginning balance (in shares)	100,037
Number of units, granted (in shares)	0
Number of units, Forfeited/Canceled (in shares)	0
Number of units, Exercised (in shares)	0
Number of units, Vested (in shares)	0
Number of units, Ending balance (in shares)	100,037	100,037
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Number of units, Beginning balance (in dollars per share)	$ 18
Number of units, Granted (in dollars per share)	0
Number of units, Forfeited/Canceled (in dollars per share)	0
Number of units, Exercised (in dollars per share)	0
Number of units, Vested (in dollars per share)	0
Number of units, Ending balance (in dollars per share)	$ 18	$ 18
Warrants | Summit Materials, LLC
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of units, Beginning balance (in shares)	100,037
Number of units, granted (in shares)	0
Number of units, Forfeited/Canceled (in shares)	0
Number of units, Exercised (in shares)	0
Number of units, Vested (in shares)	0
Number of units, Ending balance (in shares)	100,037	100,037
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Number of units, Beginning balance (in dollars per share)	$ 18
Number of units, Granted (in dollars per share)	0
Number of units, Forfeited/Canceled (in dollars per share)	0
Number of units, Exercised (in dollars per share)	0
Number of units, Vested (in dollars per share)	0
Number of units, Ending balance (in dollars per share)	$ 18	$ 18

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted Average Assumptions Used to Estimate the Fair Value of Grants (Details)	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, Minimum			2.06%
Risk-free interest rate, Maximum			2.31%
Volatility (as a percent)			47.00%
Expected term			7 years
Options | Summit Materials, LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, Minimum			2.06%
Risk-free interest rate, Maximum			2.31%
Volatility (as a percent)			47.00%
Expected term			7 years
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate (as a percent)	2.49%	2.38%	1.45%
Volatility (as a percent)	36.00%	38.00%	39.00%
Expected term	3 years	3 years	3 years
Performance Stock Units | Summit Materials, LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate (as a percent)	2.49%	2.38%	1.45%
Volatility (as a percent)	36.00%	38.00%	39.00%
Expected term	3 years	3 years	3 years

Employee Benefit Plans - Narrat

Employee Benefit Plans - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 28, 2019USD ($)plan	Dec. 29, 2018USD ($)	Dec. 30, 2017USD ($)	Jan. 02, 2016plan
Defined Benefit Plan Disclosure [Line Items]
Expense for defined contribution plans	$ 11.7	$ 11.2	$ 9.3
Number of noncontributory defined benefit pension plans | plan	2
Number of unfunded healthcare and life insurance benefit plans | plan	2
Number of unfunded healthcare plans for benefits prior to medicare eligibility | plan				1
Assumed health care cost trend rates	8.00%	8.00%
Assumed health care cost, grading	8.00%	8.00%
Expected contributions in 2020	$ 1.1
Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Expense for defined contribution plans	$ 11.7	$ 11.2	$ 9.3
Assumed health care cost trend rates	8.00%	8.00%
Assumed health care cost, grading	8.00%	8.00%
Expected contributions in 2020	$ 1.1
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation	30.00%
Equity Securities | Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Target allocation	30.00%
Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation	63.00%
Fixed Income Securities | Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Target allocation	63.00%
Cash
Defined Benefit Plan Disclosure [Line Items]
Target allocation	5.00%
Cash | Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Target allocation	5.00%
Precious metals
Defined Benefit Plan Disclosure [Line Items]
Target allocation	2.00%
Precious metals | Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Target allocation	2.00%

Employee Benefit Plans - Obliga

Employee Benefit Plans - Obligations and Funded Status (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Change in fair value of plan assets:
Beginning of period	$ 17,449
End of period	18,242	$ 17,449
Summit Materials, LLC
Change in fair value of plan assets:
Beginning of period	17,449
End of period	18,242	17,449
Pension Benefits
Change in benefit obligations:
Beginning of period	24,203	27,984
Service cost	60	67	$ 285
Interest cost	928	898	998
Actuarial (gain) loss	2,571	(3,136)
Benefits paid	(1,581)	(1,610)
End of period	26,181	24,203	27,984
Change in fair value of plan assets:
Beginning of period	17,449	19,012
Actual return on plan assets	2,055	(551)
Employer contributions	319	598
Benefits paid	(1,581)	(1,610)
End of period	18,242	17,449	19,012
Funded status of plans	(7,939)	(6,754)
Current liabilities	0	0
Noncurrent liabilities	(7,939)	(6,754)
Liability recognized	(7,939)	(6,754)
Amounts recognized in accumulated other comprehensive income:
Net actuarial (gain) loss	9,286	7,728
Prior service cost	0	0
Total amount recognized	9,286	7,728
Pension Benefits | Summit Materials, LLC
Change in benefit obligations:
Beginning of period	24,203	27,984
Service cost	60	67	285
Interest cost	928	898	998
Actuarial (gain) loss	2,571	(3,136)
Benefits paid	(1,581)	(1,610)
End of period	26,181	24,203	27,984
Change in fair value of plan assets:
Beginning of period	17,449	19,012
Actual return on plan assets	2,055	(551)
Employer contributions	319	598
Benefits paid	(1,581)	(1,610)
End of period	18,242	17,449	19,012
Funded status of plans	(7,939)	(6,754)
Current liabilities	0	0
Noncurrent liabilities	(7,939)	(6,754)
Liability recognized	(7,939)	(6,754)
Amounts recognized in accumulated other comprehensive income:
Net actuarial (gain) loss	9,286	7,728
Prior service cost	0	0
Total amount recognized	9,286	7,728
Healthcare & Life Ins
Change in benefit obligations:
Beginning of period	9,203	9,793
Service cost	166	170	184
Interest cost	321	317	365
Actuarial (gain) loss	165	(173)
Benefits paid	(765)	(904)
End of period	9,090	9,203	9,793
Change in fair value of plan assets:
Beginning of period	0	0
Actual return on plan assets	0	0
Employer contributions	765	904
Benefits paid	(765)	(904)
End of period	0	0	0
Funded status of plans	(9,090)	(9,203)
Current liabilities	(653)	(687)
Noncurrent liabilities	(8,437)	(8,516)
Liability recognized	(9,090)	(9,203)
Amounts recognized in accumulated other comprehensive income:
Net actuarial (gain) loss	2,121	1,995
Prior service cost	(1,931)	(2,172)
Total amount recognized	190	(177)
Healthcare & Life Ins | Summit Materials, LLC
Change in benefit obligations:
Beginning of period	9,203	9,793
Service cost	166	170	184
Interest cost	321	317	365
Actuarial (gain) loss	165	(173)
Benefits paid	(765)	(904)
End of period	9,090	9,203	9,793
Change in fair value of plan assets:
Beginning of period	0	0
Actual return on plan assets	0	0
Employer contributions	765	904
Benefits paid	(765)	(904)
End of period	0	0	$ 0
Funded status of plans	(9,090)	(9,203)
Current liabilities	(653)	(687)
Noncurrent liabilities	(8,437)	(8,516)
Liability recognized	(9,090)	(9,203)
Amounts recognized in accumulated other comprehensive income:
Net actuarial (gain) loss	2,121	1,995
Prior service cost	(1,931)	(2,172)
Total amount recognized	$ 190	$ (177)

Employee Benefit Plans - Amount

Employee Benefit Plans - Amounts Recognized in Other Comprehensive (Gain) Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Pension Benefits
Amounts recognized in other comprehensive (income) loss:
Net actuarial loss (gain)	$ 1,760	$ (1,300)	$ 1,068
Prior service cost	0	0	0
Amortization of prior year service cost	0	0	0
Curtailment benefit	0	0	(429)
Amortization of gain	(202)	(312)	(547)
Adjustment to plan benefits	0	0	0
Total amount recognized	1,558	(1,612)	92
Pension Benefits | Summit Materials, LLC
Amounts recognized in other comprehensive (income) loss:
Net actuarial loss (gain)	1,760	(1,300)	1,068
Prior service cost	0	0	0
Amortization of prior year service cost	0	0	0
Curtailment benefit	0	0	(429)
Amortization of gain	(202)	(312)	(547)
Adjustment to plan benefits	0	0	0
Total amount recognized	1,558	(1,612)	92
Healthcare & Life Ins
Amounts recognized in other comprehensive (income) loss:
Net actuarial loss (gain)	165	(172)	(338)
Prior service cost	0	0	(572)
Amortization of prior year service cost	241	241	168
Curtailment benefit	0	0	0
Amortization of gain	(39)	(118)	(64)
Adjustment to plan benefits	0	0	(414)
Total amount recognized	367	(49)	(1,220)
Healthcare & Life Ins | Summit Materials, LLC
Amounts recognized in other comprehensive (income) loss:
Net actuarial loss (gain)	165	(172)	(338)
Prior service cost	0	0	(572)
Amortization of prior year service cost	241	241	168
Curtailment benefit	0	0	0
Amortization of gain	(39)	(118)	(64)
Adjustment to plan benefits	0	0	(414)
Total amount recognized	$ 367	$ (49)	$ (1,220)

Employee Benefit Plans - Compon

Employee Benefit Plans - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Pension Benefits
Components of net periodic benefit cost:
Service cost	$ 60	$ 67	$ 285
Interest cost	928	898	998
Amortization of gain	202	312	547
Expected return on plan assets	(1,244)	(1,284)	(1,302)
Amortization of prior service credit	0	0	0
Net periodic (expense) benefit cost	(54)	(7)	528
Pension Benefits | Summit Materials, LLC
Components of net periodic benefit cost:
Service cost	60	67	285
Interest cost	928	898	998
Amortization of gain	202	312	547
Expected return on plan assets	(1,244)	(1,284)	(1,302)
Amortization of prior service credit	0	0	0
Net periodic (expense) benefit cost	(54)	(7)	528
Healthcare & Life Ins
Components of net periodic benefit cost:
Service cost	166	170	184
Interest cost	321	317	365
Amortization of gain	39	118	64
Expected return on plan assets	0	0	0
Amortization of prior service credit	(241)	(241)	(168)
Net periodic (expense) benefit cost	285	364	445
Healthcare & Life Ins | Summit Materials, LLC
Components of net periodic benefit cost:
Service cost	166	170	184
Interest cost	321	317	365
Amortization of gain	39	118	64
Expected return on plan assets	0	0	0
Amortization of prior service credit	(241)	(241)	(168)
Net periodic (expense) benefit cost	$ 285	$ 364	$ 445

Employee Benefit Plans - Weight

Employee Benefit Plans - Weighted-Average Assumptions Used to Determine Benefit Obligations (Detail)	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets, benefit obligation	7.00%	7.00%
Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets, benefit obligation	7.00%	7.00%
Pension Benefits | Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.78%	3.90%
Pension Benefits | Minimum | Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.78%	3.90%
Pension Benefits | Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.96%	4.02%
Pension Benefits | Maximum | Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.96%	4.02%
Healthcare & Life Ins | Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.73%	3.87%
Healthcare & Life Ins | Minimum | Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.73%	3.87%
Healthcare & Life Ins | Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.79%	3.91%
Healthcare & Life Ins | Maximum | Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.79%	3.91%

Employee Benefit Plans - Weig_2

Employee Benefit Plans - Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost (Detail)	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets, net periodic benefit cost	7.00%	7.00%	7.00%
Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets, net periodic benefit cost	7.00%	7.00%	7.00%
Pension Benefits | Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.90%	3.23%	3.61%
Pension Benefits | Minimum | Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.90%	3.23%	3.61%
Pension Benefits | Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.02%	3.37%	3.81%
Pension Benefits | Maximum | Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.02%	3.37%	3.81%
Healthcare & Life Ins | Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.87%	3.20%	3.54%
Healthcare & Life Ins | Minimum | Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.87%	3.20%	3.54%
Healthcare & Life Ins | Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.91%	3.25%	3.65%
Healthcare & Life Ins | Maximum | Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.91%	3.25%	3.65%

Employee Benefit Plans - Effect

Employee Benefit Plans - Effects of One Percentage-Point Change in Assumed Health Care Cost Trend Rates (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total service cost and interest cost components, Increase	$ 30	$ 31
APBO, Increase	773	765
Total service cost and interest cost components, Decrease	(26)	(27)
APBO, Decrease	(678)	(690)
Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total service cost and interest cost components, Increase	30	31
APBO, Increase	773	765
Total service cost and interest cost components, Decrease	(26)	(27)
APBO, Decrease	$ (678)	$ (690)

Employee Benefit Plans - Fair V

Employee Benefit Plans - Fair Value of Company's Pension Plans' Assets (Detail) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	$ 18,242	$ 17,449
Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	18,242	17,449
Intermediate—government
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	2,482	3,547
Intermediate—government | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	2,482	3,547
Intermediate—corporate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,066	3,437
Intermediate—corporate | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,066	3,437
Short-term—government
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,387	756
Short-term—government | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,387	756
Short-term—corporate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	3,173	957
Short-term—corporate | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	3,173	957
International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,387	1,143
International | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,387	1,143
U.S. Large cap value
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,225	978
U.S. Large cap value | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,225	978
U.S. Large cap growth
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,167	976
U.S. Large cap growth | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,167	976
U.S. Mid cap value
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	581	471
U.S. Mid cap value | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	581	471
U.S. Mid cap growth
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	578	496
U.S. Mid cap growth | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	578	496
U.S. Small cap value
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	583	463
U.S. Small cap value | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	583	463
U.S. Small cap growth
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	593	474
U.S. Small cap growth | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	593	474
Managed Futures
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	340	355
Managed Futures | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	340	355
International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,174	1,004
International | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,174	1,004
Emerging Markets
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	394	362
Emerging Markets | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	394	362
Commodities Broad Basket
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,118	1,048
Commodities Broad Basket | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,118	1,048
Cash
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	994	982
Cash | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	994	982
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	10,732	10,222
Quoted Prices in Active Markets for Identical Assets (Level 1) | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	10,732	10,222
Quoted Prices in Active Markets for Identical Assets (Level 1) | Intermediate—government
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	2,482	3,547
Quoted Prices in Active Markets for Identical Assets (Level 1) | Intermediate—government | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	2,482	3,547
Quoted Prices in Active Markets for Identical Assets (Level 1) | Intermediate—corporate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Intermediate—corporate | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term—government
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,387	756
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term—government | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,387	756
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term—corporate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term—corporate | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | International | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Large cap value
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,225	978
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Large cap value | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,225	978
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Large cap growth
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,167	976
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Large cap growth | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,167	976
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Mid cap value
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	581	471
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Mid cap value | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	581	471
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Mid cap growth
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	578	496
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Mid cap growth | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	578	496
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Small cap value
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	583	463
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Small cap value | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	583	463
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Small cap growth
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	593	474
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Small cap growth | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	593	474
Quoted Prices in Active Markets for Identical Assets (Level 1) | Managed Futures
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Managed Futures | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	386	329
Quoted Prices in Active Markets for Identical Assets (Level 1) | International | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	386	329
Quoted Prices in Active Markets for Identical Assets (Level 1) | Emerging Markets
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	394	362
Quoted Prices in Active Markets for Identical Assets (Level 1) | Emerging Markets | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	394	362
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commodities Broad Basket
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	362	388
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commodities Broad Basket | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	362	388
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	994	982
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	994	982
Observable Inputs (Level 2)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	7,510	7,227
Observable Inputs (Level 2) | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	7,510	7,227
Observable Inputs (Level 2) | Intermediate—government
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | Intermediate—government | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | Intermediate—corporate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,066	3,437
Observable Inputs (Level 2) | Intermediate—corporate | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,066	3,437
Observable Inputs (Level 2) | Short-term—government
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | Short-term—government | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | Short-term—corporate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	3,173	957
Observable Inputs (Level 2) | Short-term—corporate | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	3,173	957
Observable Inputs (Level 2) | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,387	1,143
Observable Inputs (Level 2) | International | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	1,387	1,143
Observable Inputs (Level 2) | U.S. Large cap value
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | U.S. Large cap value | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | U.S. Large cap growth
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | U.S. Large cap growth | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | U.S. Mid cap value
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | U.S. Mid cap value | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | U.S. Mid cap growth
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | U.S. Mid cap growth | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | U.S. Small cap value
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | U.S. Small cap value | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | U.S. Small cap growth
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | U.S. Small cap growth | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | Managed Futures
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	340	355
Observable Inputs (Level 2) | Managed Futures | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	340	355
Observable Inputs (Level 2) | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	788	675
Observable Inputs (Level 2) | International | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	788	675
Observable Inputs (Level 2) | Emerging Markets
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | Emerging Markets | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | Commodities Broad Basket
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	756	660
Observable Inputs (Level 2) | Commodities Broad Basket | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	756	660
Observable Inputs (Level 2) | Cash
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	0	0
Observable Inputs (Level 2) | Cash | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value	$ 0	$ 0

Employee Benefit Plans - Estima

Employee Benefit Plans - Estimated Benefit Payments (Detail) $ in Thousands	Dec. 28, 2019USD ($)
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2020	$ 1,718
2021	1,681
2022	1,680
2023	1,679
2024	1,635
2025 - 2029	7,671
Pension Benefits | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2020	1,718
2021	1,681
2022	1,680
2023	1,679
2024	1,635
2025 - 2029	7,671
Healthcare & Life Ins
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2020	653
2021	638
2022	628
2023	618
2024	630
2025 - 2029	3,211
Healthcare & Life Ins | Summit Materials, LLC
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2020	653
2021	638
2022	628
2023	618
2024	630
2025 - 2029	$ 3,211

Employee Benefit Plans - Multie

Employee Benefit Plans - Multiemployer Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Multiemployer Plans [Line Items]
Contributions of Company	$ 135	$ 141
Construction Industry Laborers Pension Fund
Multiemployer Plans [Line Items]
Contributions of Company	112	115
Operating Engineers Local 101 Pension Plan
Multiemployer Plans [Line Items]
Contributions of Company	23	26
Summit Materials, LLC
Multiemployer Plans [Line Items]
Contributions of Company	135	141
Summit Materials, LLC | Construction Industry Laborers Pension Fund
Multiemployer Plans [Line Items]
Contributions of Company	112	115
Summit Materials, LLC | Operating Engineers Local 101 Pension Plan
Multiemployer Plans [Line Items]
Contributions of Company	$ 23	$ 26

Accrued Mining and Landfill R_3

Accrued Mining and Landfill Reclamation - Narrative (Detail) - USD ($) $ in Millions	Dec. 28, 2019	Dec. 29, 2018
Asset Retirement Obligations [Line Items]
Anticipated costs	$ 97.4	$ 92.5
Accrued expenses
Asset Retirement Obligations [Line Items]
Asset retirement obligation, current	7.9	4.1
Summit Materials, LLC
Asset Retirement Obligations [Line Items]
Anticipated costs	97.4	92.5
Summit Materials, LLC | Accrued expenses
Asset Retirement Obligations [Line Items]
Asset retirement obligation, current	$ 7.9	$ 4.1

Accrued Mining and Landfill R_4

Accrued Mining and Landfill Reclamation - Activity for Asset Retirement Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Asset Retirement Obligation, Activity
Beginning balance	$ 30,999	$ 24,329
Acquired obligations	805	3,937
Change in cost estimate	4,468	2,808
Settlement of reclamation obligations	(1,812)	(1,680)
Accretion expense	2,216	1,605	$ 1,875
Ending balance	36,676	30,999	24,329
Summit Materials, LLC
Asset Retirement Obligation, Activity
Beginning balance	30,999	24,329
Acquired obligations	805	3,937
Change in cost estimate	4,468	2,808
Settlement of reclamation obligations	(1,812)	(1,680)
Accretion expense	2,216	1,605	1,875
Ending balance	$ 36,676	$ 30,999	$ 24,329

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details)	12 Months Ended
	Dec. 28, 2019
Loss Contingencies [Line Items]
Term of purchase commitments	1 year
Summit Materials, LLC
Loss Contingencies [Line Items]
Term of purchase commitments	1 year

Leases - Operating and Finance

Leases - Operating and Finance Leases (Details) $ in Thousands	12 Months Ended
	Dec. 28, 2019USD ($)
Lease, Cost [Abstract]
Operating lease cost	$ 10,451
Variable lease cost	423
Short-term lease cost	38,417
Financing lease cost:
Amortization of right-of-use assets	11,062
Interest on lease liabilities	3,171
Total lease cost	63,524
Operating leases:
Operating lease right-of-use assets	32,777
Current operating lease liabilities	8,427
Noncurrent operating lease liabilities	25,381
Total operating lease liabilities	33,808
Finance leases:
Property and equipment, gross	82,660
Less accumulated depreciation	(24,907)
Property and equipment, net	57,753
Current finance lease liabilities	16,007
Long-term finance lease liabilities	40,410
Total finance lease liabilities	$ 56,417
Lease Term
Operating leases	8 years 7 months 6 days
Finance lease	2 years 7 months 6 days
Discount Rate
Operating leases	5.50%
Finance lease	5.50%
Operating Leases
2020	$ 9,958
2021	7,960
2022	4,852
2023	3,842
2024	2,246
Thereafter	14,292
Total lease payments	43,150
Less imputed interest	(9,342)
Finance Leases
2020	18,646
2021	21,886
2022	14,940
2023	1,732
2024	2,252
Thereafter	2,829
Total lease payments	62,285
Less imputed interest	(5,868)
Summit Materials, LLC
Lease, Cost [Abstract]
Operating lease cost	10,451
Variable lease cost	423
Short-term lease cost	38,417
Financing lease cost:
Amortization of right-of-use assets	11,062
Interest on lease liabilities	3,171
Total lease cost	63,524
Operating leases:
Operating lease right-of-use assets	32,777
Current operating lease liabilities	8,427
Noncurrent operating lease liabilities	25,381
Total operating lease liabilities	33,808
Finance leases:
Property and equipment, gross	82,660
Less accumulated depreciation	(24,907)
Property and equipment, net	57,753
Current finance lease liabilities	16,007
Long-term finance lease liabilities	40,410
Total finance lease liabilities	$ 56,417
Lease Term
Operating leases	8 years 7 months 6 days
Finance lease	2 years 7 months 6 days
Discount Rate
Operating leases	5.50%
Finance lease	5.50%
Operating Leases
2020	$ 9,958
2021	7,960
2022	4,852
2023	3,842
2024	2,246
Thereafter	14,292
Total lease payments	43,150
Less imputed interest	(9,342)
Finance Leases
2020	18,646
2021	21,886
2022	14,940
2023	1,732
2024	2,252
Thereafter	2,829
Total lease payments	62,285
Less imputed interest	$ (5,868)

Leases - Narrative (Detail)

Leases - Narrative (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Operating Leased Assets [Line Items]
Royalty expense recorded in cost of revenue	$ 24.3	$ 20.1	$ 18.7
Summit Materials, LLC
Operating Leased Assets [Line Items]
Royalty expense recorded in cost of revenue	$ 24.3	$ 20.1	$ 18.7

Leases - Schedule of Minimum Co

Leases - Schedule of Minimum Contractual Agreements Under Royalty Agreements (Details) $ in Thousands	Dec. 28, 2019USD ($)
Royalty Agreements
2020	$ 7,555
2021	7,212
2022	7,214
2023	7,216
2024	6,613
Summit Materials, LLC
Royalty Agreements
2020	7,555
2021	7,212
2022	7,214
2023	7,216
2024	$ 6,613

Fair Value of Financial Instr_2

Fair Value of Financial Instruments - Narrative (Details) $ in Millions	Dec. 28, 2019USD ($)
Interest rate derivatives | Term Loan, due 2022 | Cash flow hedges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Term loan borrowings hedged by derivatives	$ 200
Interest rate derivatives | Term Loan, due 2022 | Cash flow hedges | Summit Materials, LLC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Term loan borrowings hedged by derivatives	$ 200
Discount Rate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.100
Discount Rate | Level 3 | Summit Materials, LLC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	0.100

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of acquisition-related liabilities and Accrued expenses - Contingent consideration	$ 1,967	$ 1,394
Acquisition-related liabilities and Other noncurrent liabilities - Contingent consideration	1,302	5,175
Cash flow hedges | Interest rate derivatives | Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of acquisition-related liabilities and Accrued expenses - Cash flow hedge	0	0
Acquisition-related liabilities and Other noncurrent liabilities - Cash flow hedge	0	0
Summit Materials, LLC | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of acquisition-related liabilities and Accrued expenses - Contingent consideration	1,967	1,394
Acquisition-related liabilities and Other noncurrent liabilities - Contingent consideration	1,302	5,175
Summit Materials, LLC | Cash flow hedges | Interest rate derivatives | Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of acquisition-related liabilities and Accrued expenses - Cash flow hedge	0	0
Acquisition-related liabilities and Other noncurrent liabilities - Cash flow hedge	$ 0	$ 0

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Carrying Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Financial Instruments
Current portion of debt	$ 7,942	$ 6,354
Summit Materials, LLC
Financial Instruments
Current portion of debt	7,942	6,354
Level 2
Financial Instruments
Current portion of debt		6,400
Level 2 | Fair Value
Financial Instruments
Long-term debt	1,918,720	1,777,722
Current portion of debt	7,900
Level 2 | Carrying Value
Financial Instruments
Long-term debt	1,872,273	1,828,159
Level 2 | Summit Materials, LLC
Financial Instruments
Current portion of debt	7,900	6,400
Level 2 | Summit Materials, LLC | Fair Value
Financial Instruments
Long-term debt	1,918,720	1,777,722
Level 2 | Summit Materials, LLC | Carrying Value
Financial Instruments
Long-term debt	1,872,273	1,828,159
Level 3 | Fair Value
Financial Instruments
Current portion of deferred consideration and noncompete obligations	30,733	32,876
Long term portion of deferred consideration and noncompete obligations	18,499	44,293
Level 3 | Carrying Value
Financial Instruments
Current portion of deferred consideration and noncompete obligations	30,733	32,876
Long term portion of deferred consideration and noncompete obligations	18,499	44,293
Level 3 | Summit Materials, LLC | Fair Value
Financial Instruments
Current portion of deferred consideration and noncompete obligations	28,233	30,376
Long term portion of deferred consideration and noncompete obligations	16,364	40,179
Level 3 | Summit Materials, LLC | Carrying Value
Financial Instruments
Current portion of deferred consideration and noncompete obligations	28,233	30,376
Long term portion of deferred consideration and noncompete obligations	$ 16,364	$ 40,179

Segment Information - Narrative

Segment Information - Narrative (Details)	12 Months Ended
	Dec. 28, 2019segment
Segment Reporting Information [Line Items]
Number of operating segments	3
Number of reportable segments	3
Summit Materials, LLC
Segment Reporting Information [Line Items]
Number of operating segments	3
Number of reportable segments	3

Segment Information - Financial

Segment Information - Financial Data (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 506,259	$ 665,847	$ 552,591	$ 305,950	$ 445,090	$ 625,017	$ 549,235	$ 289,916	$ 2,222,140	$ 2,101,002	$ 1,932,575
Income (loss) from operations before taxes									78,224	96,077	(158,200)
Interest expense									116,509	116,548	108,549
Depreciation, depletion and amortization									214,886	203,305	177,643
Accretion									2,216	1,605	1,875
Loss on debt financings									14,565	149	4,815
Tax receivable agreement expense (benefit)									16,237	(22,684)	271,016
Gain on sale of business									0	(12,108)	0
Transaction costs									2,222	4,238	7,733
Non-cash compensation									20,403	25,378	21,140
Other									(3,800)	(6,247)	1,206
Total Adjusted EBITDA									461,462	406,261	435,777
Total purchases of property, plant and equipment									177,495	220,685	194,146
Total depreciation, depletion, amortization and accretion									217,102	204,910	179,518
Total assets	4,067,556				3,857,641				4,067,556	3,857,641	3,787,333
Summit Materials, LLC
Segment Reporting Information [Line Items]
Revenue	506,259	$ 665,847	$ 552,591	$ 305,950	445,090	$ 625,017	$ 549,235	$ 289,916	2,222,140	2,101,002	1,932,575
Income (loss) from operations before taxes									94,982	74,110	113,696
Interest expense									115,988	115,831	107,655
Depreciation, depletion and amortization									214,886	203,305	177,643
Accretion									2,216	1,605	1,875
Loss on debt financings									14,565	149	4,815
Gain on sale of business									0	(12,108)	0
Transaction costs									2,222	4,238	7,733
Non-cash compensation									20,403	25,378	21,140
Other									(3,800)	(6,247)	1,206
Total Adjusted EBITDA									461,462	406,261	435,763
Total purchases of property, plant and equipment									177,495	220,685	194,146
Total depreciation, depletion, amortization and accretion									217,102	204,910	179,518
Total assets	3,856,223				3,633,244				3,856,223	3,633,244	3,504,241
West
Segment Reporting Information [Line Items]
Revenue									1,122,338	1,117,066	998,843
West | Summit Materials, LLC
Segment Reporting Information [Line Items]
Revenue									1,122,338	1,117,066	998,843
East
Segment Reporting Information [Line Items]
Revenue									809,098	703,147	629,919
East | Summit Materials, LLC
Segment Reporting Information [Line Items]
Revenue									809,098	703,147	629,919
Cement
Segment Reporting Information [Line Items]
Revenue									290,704	280,789	303,813
Cement | Summit Materials, LLC
Segment Reporting Information [Line Items]
Revenue									290,704	280,789	303,813
Operating segment
Segment Reporting Information [Line Items]
Total purchases of property, plant and equipment									174,982	213,077	187,950
Total depreciation, depletion, amortization and accretion									213,106	202,288	176,917
Total assets	3,537,047				3,501,727				3,537,047	3,501,727	3,131,724
Operating segment | Summit Materials, LLC
Segment Reporting Information [Line Items]
Total purchases of property, plant and equipment									174,982	213,077	187,950
Total depreciation, depletion, amortization and accretion									213,106	202,288	176,917
Total assets	3,537,047				3,501,727				3,537,047	3,501,727	3,131,724
Operating segment | West
Segment Reporting Information [Line Items]
Total Adjusted EBITDA									204,964	188,999	203,590
Total purchases of property, plant and equipment									71,397	120,657	83,591
Total depreciation, depletion, amortization and accretion									93,256	91,794	71,314
Total assets	1,379,684				1,370,501				1,379,684	1,370,501	1,225,463
Operating segment | West | Summit Materials, LLC
Segment Reporting Information [Line Items]
Total Adjusted EBITDA									204,964	188,999	203,590
Total purchases of property, plant and equipment									71,397	120,657	83,591
Total depreciation, depletion, amortization and accretion									93,256	91,794	71,314
Total assets	1,379,684				1,370,501				1,379,684	1,370,501	1,225,463
Operating segment | East
Segment Reporting Information [Line Items]
Total Adjusted EBITDA									187,625	138,032	139,108
Total purchases of property, plant and equipment									77,894	64,384	68,556
Total depreciation, depletion, amortization and accretion									81,403	75,433	67,252
Total assets	1,288,835				1,253,640				1,288,835	1,253,640	1,035,609
Operating segment | East | Summit Materials, LLC
Segment Reporting Information [Line Items]
Total Adjusted EBITDA									187,625	138,032	139,108
Total purchases of property, plant and equipment									77,894	64,384	68,556
Total depreciation, depletion, amortization and accretion									81,403	75,433	67,252
Total assets	1,288,835				1,253,640				1,288,835	1,253,640	1,035,609
Operating segment | Cement
Segment Reporting Information [Line Items]
Total Adjusted EBITDA									103,438	111,394	127,547
Total purchases of property, plant and equipment									25,691	28,036	35,803
Total depreciation, depletion, amortization and accretion									38,447	35,061	38,351
Total assets	868,528				877,586				868,528	877,586	870,652
Operating segment | Cement | Summit Materials, LLC
Segment Reporting Information [Line Items]
Total Adjusted EBITDA									103,438	111,394	127,547
Total purchases of property, plant and equipment									25,691	28,036	35,803
Total depreciation, depletion, amortization and accretion									38,447	35,061	38,351
Total assets	868,528				877,586				868,528	877,586	870,652
Corporate and other
Segment Reporting Information [Line Items]
Total Adjusted EBITDA									(34,565)	(32,164)	(34,468)
Total purchases of property, plant and equipment									2,513	7,608	6,196
Total depreciation, depletion, amortization and accretion									3,996	2,622	2,601
Total assets	530,509				355,914				530,509	355,914	655,609
Corporate and other | Summit Materials, LLC
Segment Reporting Information [Line Items]
Total Adjusted EBITDA									(34,565)	(32,164)	(34,482)
Total purchases of property, plant and equipment									2,513	7,608	6,196
Total depreciation, depletion, amortization and accretion									3,996	2,622	2,601
Total assets	$ 319,176				$ 131,517				$ 319,176	$ 131,517	$ 372,517

Senior Notes' Guarantor and N_3

Senior Notes' Guarantor and Non-Guarantor Financial Information - Schedule of Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 311,319	$ 128,508
Accounts receivable, net	253,256	214,518
Costs and estimated earnings in excess of billings	13,088	18,602
Inventories	204,787	213,851
Other current assets	13,831	16,061
Total current assets	796,281	591,540
Property, plant and equipment including finance lease right-of-use assets, net	1,747,449
Property, plant and equipment, net		1,780,132
Goodwill	1,199,699	1,192,028	$ 1,036,320
Intangible assets, net	23,498	18,460
Operating lease right-of-use assets	32,777
Other assets	55,519	50,084
Total assets	4,067,556	3,857,641	3,787,333
Current liabilities:
Current portion of debt	7,942	6,354
Current portion of acquisition-related liabilities	32,700	34,270
Accounts payable	116,359	107,702
Accrued expenses	120,005	100,491
Current operating lease liabilities	8,427
Billings in excess of costs and estimated earnings	13,864	11,840
Total current liabilities	299,297	260,657
Long-term debt	1,851,057	1,807,502
Acquisition-related liabilities	19,801	49,468
Noncurrent operating lease liabilities	25,381
Other noncurrent liabilities	100,282	88,195
Total liabilities	2,622,783	2,515,496
Total liabilities and stockholders' equity / member's interest	4,067,556	3,857,641
Summit Materials, LLC
Current assets:
Cash and cash equivalents	311,319	128,508
Accounts receivable, net	253,256	214,518
Intercompany receivables	0	0
Costs and estimated earnings in excess of billings	13,088	18,602
Inventories	204,787	213,851
Other current assets	13,831	16,061
Total current assets	796,281	591,540
Property, plant and equipment including finance lease right-of-use assets, net	1,747,449
Property, plant and equipment, net		1,780,132
Goodwill	1,200,699	1,193,028	1,037,320
Intangible assets, net	23,498	18,460
Operating lease right-of-use assets	32,777
Other assets	55,519	50,084
Total assets	3,856,223	3,633,244	3,504,241
Current liabilities:
Current portion of debt	7,942	6,354
Current portion of acquisition-related liabilities	30,200	31,770
Accounts payable	116,970	109,008
Accrued expenses	120,237	100,029
Current operating lease liabilities	8,427
Intercompany payables	0	0
Billings in excess of costs and estimated earnings	13,864	11,840
Total current liabilities	297,640	259,001
Long-term debt	1,851,057	1,807,502
Acquisition-related liabilities	17,666	45,354
Noncurrent operating lease liabilities	25,381
Other noncurrent liabilities	151,329	135,956
Total liabilities	2,343,073	2,247,813
Total member's interest	1,513,150	1,385,431	$ 1,291,594	$ 876,393
Total liabilities and stockholders' equity / member's interest	3,856,223	3,633,244
Summit Materials, LLC | Eliminations
Current assets:
Cash and cash equivalents	(6,477)	(4,870)
Accounts receivable, net	(33)	(185)
Intercompany receivables	(1,385,708)	(1,125,192)
Costs and estimated earnings in excess of billings	0	0
Inventories	0	0
Other current assets	0	0
Total current assets	(1,392,218)	(1,130,247)
Property, plant and equipment including finance lease right-of-use assets, net	0
Property, plant and equipment, net		0
Goodwill	0	0
Intangible assets, net	0	0
Operating lease right-of-use assets	0
Other assets	(3,709,690)	(3,397,794)
Total assets	(5,101,908)	(4,528,041)
Current liabilities:
Current portion of debt	0	0
Current portion of acquisition-related liabilities	0	0
Accounts payable	(33)	(185)
Accrued expenses	(6,477)	(4,870)
Current operating lease liabilities	0
Intercompany payables	(1,385,708)	(1,125,192)
Billings in excess of costs and estimated earnings	0	0
Total current liabilities	(1,392,218)	(1,130,247)
Long-term debt	0	0
Acquisition-related liabilities	0	0
Noncurrent operating lease liabilities	0
Other noncurrent liabilities	(137,018)	(171,317)
Total liabilities	(1,529,236)	(1,301,564)
Total member's interest	(3,572,672)	(3,226,477)
Total liabilities and stockholders' equity / member's interest	(5,101,908)	(4,528,041)
Issuers | Summit Materials, LLC | Reportable Legal Entities
Current assets:
Cash and cash equivalents	302,474	117,219
Accounts receivable, net	0	0
Intercompany receivables	443,323	500,765
Costs and estimated earnings in excess of billings	0	0
Inventories	0	0
Other current assets	1,763	1,953
Total current assets	747,560	619,937
Property, plant and equipment including finance lease right-of-use assets, net	11,602
Property, plant and equipment, net		13,300
Goodwill	0	0
Intangible assets, net	0	0
Operating lease right-of-use assets	3,316
Other assets	3,596,161	3,292,851
Total assets	4,358,639	3,926,088
Current liabilities:
Current portion of debt	7,942	6,354
Current portion of acquisition-related liabilities	0	0
Accounts payable	4,588	4,712
Accrued expenses	51,043	45,146
Current operating lease liabilities	764
Intercompany payables	922,356	673,175
Billings in excess of costs and estimated earnings	0	0
Total current liabilities	986,693	729,387
Long-term debt	1,851,057	1,807,502
Acquisition-related liabilities	0	0
Noncurrent operating lease liabilities	3,480
Other noncurrent liabilities	4,259	3,768
Total liabilities	2,845,489	2,540,657
Total member's interest	1,513,150	1,385,431
Total liabilities and stockholders' equity / member's interest	4,358,639	3,926,088
100% Owned Guarantors | Summit Materials, LLC | Reportable Legal Entities
Current assets:
Cash and cash equivalents	5,488	8,440
Accounts receivable, net	234,053	199,538
Intercompany receivables	942,385	624,427
Costs and estimated earnings in excess of billings	12,291	17,711
Inventories	199,794	210,149
Other current assets	10,308	11,308
Total current assets	1,404,319	1,071,573
Property, plant and equipment including finance lease right-of-use assets, net	1,674,443
Property, plant and equipment, net		1,709,083
Goodwill	1,142,063	1,136,785
Intangible assets, net	23,498	18,460
Operating lease right-of-use assets	24,551
Other assets	168,314	154,080
Total assets	4,437,188	4,089,981
Current liabilities:
Current portion of debt	0	0
Current portion of acquisition-related liabilities	30,200	31,770
Accounts payable	103,812	92,132
Accrued expenses	72,970	57,826
Current operating lease liabilities	6,571
Intercompany payables	447,827	436,564
Billings in excess of costs and estimated earnings	12,183	11,347
Total current liabilities	673,563	629,639
Long-term debt	0	0
Acquisition-related liabilities	17,666	45,354
Noncurrent operating lease liabilities	18,047
Other noncurrent liabilities	203,919	226,137
Total liabilities	913,195	901,130
Total member's interest	3,523,993	3,188,851
Total liabilities and stockholders' equity / member's interest	4,437,188	4,089,981
Non-Guarantors | Summit Materials, LLC | Reportable Legal Entities
Current assets:
Cash and cash equivalents	9,834	7,719
Accounts receivable, net	19,236	15,165
Intercompany receivables	0	0
Costs and estimated earnings in excess of billings	797	891
Inventories	4,993	3,702
Other current assets	1,760	2,800
Total current assets	36,620	30,277
Property, plant and equipment including finance lease right-of-use assets, net	61,404
Property, plant and equipment, net		57,749
Goodwill	58,636	56,243
Intangible assets, net	0	0
Operating lease right-of-use assets	4,910
Other assets	734	947
Total assets	162,304	145,216
Current liabilities:
Current portion of debt	0	0
Current portion of acquisition-related liabilities	0	0
Accounts payable	8,603	12,349
Accrued expenses	2,701	1,927
Current operating lease liabilities	1,092
Intercompany payables	15,525	15,453
Billings in excess of costs and estimated earnings	1,681	493
Total current liabilities	29,602	30,222
Long-term debt	0	0
Acquisition-related liabilities	0	0
Noncurrent operating lease liabilities	3,854
Other noncurrent liabilities	80,169	77,368
Total liabilities	113,625	107,590
Total member's interest	48,679	37,626
Total liabilities and stockholders' equity / member's interest	$ 162,304	$ 145,216

Senior Notes' Guarantor and N_4

Senior Notes' Guarantor and Non-Guarantor Financial Information - Schedule of Condensed Consolidating Statements of Operations and Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Condensed Financial Statements, Captions [Line Items]
Revenue	$ 506,259	$ 665,847	$ 552,591	$ 305,950	$ 445,090	$ 625,017	$ 549,235	$ 289,916	$ 2,222,140	$ 2,101,002	$ 1,932,575
Cost of revenue									1,526,332	1,475,779	1,281,777
Depreciation, depletion, amortization and accretion									217,102	204,910	179,518
Operating income	59,926	130,881	80,422	(57,671)	28,545	108,167	77,279	(51,525)	213,558	162,466	220,877
Gain on sale of business									0	(12,108)	0
Income (loss) from operations before taxes									78,224	96,077	(158,200)
Income tax expense (benefit)									17,101	59,747	(283,977)
Net income	36,397	58,237	37,990	(71,501)	(18,627)	73,992	36,913	(55,948)	61,123	36,330	125,777
Net income attributable to Summit Inc.	35,671	55,757	36,410	(68,772)	(19,163)	71,289	35,509	(53,729)	59,066	33,906	121,830
Comprehensive income (loss) income attributable to member of Summit Materials, LLC									59,833	29,201	131,465
Summit Materials, LLC
Condensed Financial Statements, Captions [Line Items]
Revenue	506,259	665,847	552,591	305,950	445,090	625,017	549,235	289,916	2,222,140	2,101,002	1,932,575
Cost of revenue									1,526,332	1,475,779	1,281,777
General and administrative expenses									265,148	257,847	250,403
Depreciation, depletion, amortization and accretion									217,102	204,910	179,518
Operating income	59,926	130,881	80,422	(57,671)	28,545	108,167	77,279	(51,525)	213,558	162,466	220,877
Other (income) loss, net									2,588	(15,367)	(474)
Interest expense (income)									115,988	115,831	107,655
Gain on sale of business									0	(12,108)	0
Income (loss) from operations before taxes									94,982	74,110	113,696
Income tax expense (benefit)									6,385	10,273	(20,345)
Net income	$ 41,461	$ 85,199	$ 53,501	$ (91,564)	$ (4,596)	$ 90,427	$ 46,602	$ (68,596)	88,597	63,837	134,041
Net income (loss) attributable to noncontrolling interest									0	0	(27)
Net income attributable to Summit Inc.									88,597	63,837	134,068
Comprehensive income (loss) income attributable to member of Summit Materials, LLC									91,242	57,356	144,377
Summit Materials, LLC | Eliminations
Condensed Financial Statements, Captions [Line Items]
Revenue									(12,196)	(6,084)	(5,879)
Cost of revenue									(12,196)	(6,084)	(5,879)
General and administrative expenses									0	0	0
Depreciation, depletion, amortization and accretion									0	0	0
Operating income									0	0	0
Other (income) loss, net									291,662	247,657	309,860
Interest expense (income)									0	0	0
Gain on sale of business										0
Income (loss) from operations before taxes									(291,662)	(247,657)	(309,860)
Income tax expense (benefit)									0	0	0
Net income											(309,860)
Net income (loss) attributable to noncontrolling interest											(27)
Net income attributable to Summit Inc.									(291,662)	(247,657)	(309,833)
Comprehensive income (loss) income attributable to member of Summit Materials, LLC									(289,017)	(254,138)	(299,524)
Summit Materials, LLC | Issuers | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Revenue									0	0	0
Cost of revenue									0	0	0
General and administrative expenses									58,099	62,376	63,954
Depreciation, depletion, amortization and accretion									3,997	2,622	2,601
Operating income									(62,096)	(64,998)	(66,555)
Other (income) loss, net									(279,517)	(249,204)	(307,876)
Interest expense (income)									127,734	118,857	105,735
Gain on sale of business										0
Income (loss) from operations before taxes									89,687	65,349	135,586
Income tax expense (benefit)									1,090	1,512	1,518
Net income											134,068
Net income (loss) attributable to noncontrolling interest											0
Net income attributable to Summit Inc.									88,597	63,837	134,068
Comprehensive income (loss) income attributable to member of Summit Materials, LLC									91,242	57,356	144,377
Summit Materials, LLC | 100% Owned Guarantors | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Revenue									2,139,457	2,018,428	1,854,434
Cost of revenue									1,473,124	1,416,222	1,227,037
General and administrative expenses									195,683	184,917	178,023
Depreciation, depletion, amortization and accretion									207,277	197,406	172,738
Operating income									263,373	219,883	276,636
Other (income) loss, net									(8,767)	(14,643)	(1,925)
Interest expense (income)									(16,561)	(7,818)	(2,415)
Gain on sale of business										(12,108)
Income (loss) from operations before taxes									288,701	254,452	280,976
Income tax expense (benefit)									3,377	8,226	(23,774)
Net income											304,750
Net income (loss) attributable to noncontrolling interest											0
Net income attributable to Summit Inc.									285,324	246,226	304,750
Comprehensive income (loss) income attributable to member of Summit Materials, LLC									287,395	243,359	302,209
Summit Materials, LLC | Non-Guarantors | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Revenue									94,879	88,658	84,020
Cost of revenue									65,404	65,641	60,619
General and administrative expenses									11,366	10,554	8,426
Depreciation, depletion, amortization and accretion									5,828	4,882	4,179
Operating income									12,281	7,581	10,796
Other (income) loss, net									(790)	823	(533)
Interest expense (income)									4,815	4,792	4,335
Gain on sale of business										0
Income (loss) from operations before taxes									8,256	1,966	6,994
Income tax expense (benefit)									1,918	535	1,911
Net income											5,083
Net income (loss) attributable to noncontrolling interest											0
Net income attributable to Summit Inc.									6,338	1,431	5,083
Comprehensive income (loss) income attributable to member of Summit Materials, LLC									$ 1,622	$ 10,779	$ (2,685)

Senior Notes' Guarantor and N_5

Senior Notes' Guarantor and Non-Guarantor Financial Information - Schedule of Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	$ 337,184	$ 209,368	$ 292,183
Cash flow from investing activities:
Acquisitions, net of cash acquired	(5,392)	(246,017)	(374,930)
Purchase of property, plant and equipment	(177,495)	(220,685)	(194,146)
Proceeds from the sale of property, plant, and equipment	21,173	21,635	17,072
Proceeds from sale of business	0	21,564	0
Other	(1,095)	3,804	(471)
Net cash used for investing activities	(162,809)	(419,699)	(552,475)
Cash flow from financing activities:
Capital issuance costs	0	0	(627)
Net proceeds from debt issuance	300,000	64,500	302,000
Payments on long-term debt	(270,229)	(85,042)	(16,438)
Purchase of noncontrolling interests	0	0	(532)
Payments on acquisition-related liabilities	(33,883)	(36,504)	(34,650)
Debt issuance costs	(6,312)	(550)	(6,416)
Distributions from partnership	0	(69)	(1,974)
Other	(502)	(1,943)	(869)
Net cash provided by (used in) financing activities	8,150	(43,993)	499,755
Impact of foreign currency on cash	286	(724)	701
Net increase (decrease) in cash	182,811	(255,048)	240,164
Cash and cash equivalents—beginning of period	128,508	383,556	143,392
Cash and cash equivalents—end of period	311,319	128,508	383,556
Summit Materials, LLC
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	337,184	209,368	295,132
Cash flow from investing activities:
Acquisitions, net of cash acquired	(5,392)	(246,017)	(374,930)
Purchase of property, plant and equipment	(177,495)	(220,685)	(194,146)
Proceeds from the sale of property, plant, and equipment	21,173	21,635	17,072
Proceeds from sale of business	0	21,564	0
Other	(1,095)	3,804	(471)
Net cash used for investing activities	(162,809)	(419,699)	(552,475)
Cash flow from financing activities:
Proceeds from investment by member	19,076	15,615	304,541
Capital issuance costs	0	0	(627)
Net proceeds from debt issuance	300,000	64,500	302,000
Loans received from and payments made on loans from other Summit Companies	0	0	0
Payments on long-term debt	(270,229)	(85,042)	(16,438)
Purchase of noncontrolling interests	0	0	(532)
Payments on acquisition-related liabilities	(31,383)	(34,004)	(32,150)
Debt issuance costs	(6,312)	(550)	(6,416)
Distributions from partnership	(2,500)	(2,569)	(51,986)
Other	(502)	(1,943)	(866)
Net cash provided by (used in) financing activities	8,150	(43,993)	497,526
Impact of foreign currency on cash	286	(724)	701
Net increase (decrease) in cash	182,811	(255,048)	240,884
Cash and cash equivalents—beginning of period	128,508	383,556	142,672
Cash and cash equivalents—end of period	311,319	128,508	383,556
Summit Materials, LLC | Eliminations
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	0	0	0
Cash flow from investing activities:
Acquisitions, net of cash acquired	0	0	0
Purchase of property, plant and equipment	0	0	0
Proceeds from the sale of property, plant, and equipment	0	0	0
Proceeds from sale of business		0
Other	0	0	0
Net cash used for investing activities	0	0	0
Cash flow from financing activities:
Proceeds from investment by member	0	0	0
Capital issuance costs			0
Net proceeds from debt issuance	0	0	0
Loans received from and payments made on loans from other Summit Companies	(1,607)	7,502	(1,706)
Payments on long-term debt	0	0	0
Purchase of noncontrolling interests			0
Payments on acquisition-related liabilities	0	0	0
Debt issuance costs	0	0	0
Distributions from partnership	0	0	0
Other	0	0	0
Net cash provided by (used in) financing activities	(1,607)	7,502	(1,706)
Impact of foreign currency on cash	0	0	0
Net increase (decrease) in cash	(1,607)	7,502	(1,706)
Cash and cash equivalents—beginning of period	(4,870)	(12,372)	(10,666)
Cash and cash equivalents—end of period	(6,477)	(4,870)	(12,372)
Issuers | Summit Materials, LLC | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	(112,019)	(142,315)	(127,102)
Cash flow from investing activities:
Acquisitions, net of cash acquired	0	0	(24,538)
Purchase of property, plant and equipment	(2,513)	(7,607)	(6,196)
Proceeds from the sale of property, plant, and equipment	0	0	0
Proceeds from sale of business		0
Other	0	0	0
Net cash used for investing activities	(2,513)	(7,607)	(30,734)
Cash flow from financing activities:
Proceeds from investment by member	(21,614)	(146,533)	40,913
Capital issuance costs			(627)
Net proceeds from debt issuance	300,000	64,500	302,000
Loans received from and payments made on loans from other Summit Companies	287,029	51,696	119,858
Payments on long-term debt	(256,354)	(69,265)	(8,463)
Purchase of noncontrolling interests			0
Payments on acquisition-related liabilities	0	0	0
Debt issuance costs	(6,312)	(550)	(6,416)
Distributions from partnership	(2,500)	(2,569)	(51,986)
Other	(462)	(879)	(564)
Net cash provided by (used in) financing activities	299,787	(103,600)	394,715
Impact of foreign currency on cash	0	0	0
Net increase (decrease) in cash	185,255	(253,522)	236,879
Cash and cash equivalents—beginning of period	117,219	370,741	133,862
Cash and cash equivalents—end of period	302,474	117,219	370,741
100% Owned Guarantors | Summit Materials, LLC | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	431,323	340,401	392,316
Cash flow from investing activities:
Acquisitions, net of cash acquired	(5,392)	(246,017)	(324,892)
Purchase of property, plant and equipment	(163,652)	(188,435)	(182,295)
Proceeds from the sale of property, plant, and equipment	21,083	21,263	16,822
Proceeds from sale of business		21,564
Other	(1,095)	3,804	(471)
Net cash used for investing activities	(149,056)	(387,821)	(490,836)
Cash flow from financing activities:
Proceeds from investment by member	40,690	162,148	252,911
Capital issuance costs			0
Net proceeds from debt issuance	0	0	0
Loans received from and payments made on loans from other Summit Companies	(280,836)	(65,845)	(108,026)
Payments on long-term debt	(13,650)	(15,662)	(7,967)
Purchase of noncontrolling interests			(532)
Payments on acquisition-related liabilities	(31,383)	(34,004)	(32,150)
Debt issuance costs	0	0	0
Distributions from partnership	0	0	0
Other	(40)	(1,031)	(282)
Net cash provided by (used in) financing activities	(285,219)	45,606	103,954
Impact of foreign currency on cash	0	0	0
Net increase (decrease) in cash	(2,952)	(1,814)	5,434
Cash and cash equivalents—beginning of period	8,440	10,254	4,820
Cash and cash equivalents—end of period	5,488	8,440	10,254
Non-Guarantors | Summit Materials, LLC | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	17,880	11,282	29,918
Cash flow from investing activities:
Acquisitions, net of cash acquired	0	0	(25,500)
Purchase of property, plant and equipment	(11,330)	(24,643)	(5,655)
Proceeds from the sale of property, plant, and equipment	90	372	250
Proceeds from sale of business		0
Other	0	0	0
Net cash used for investing activities	(11,240)	(24,271)	(30,905)
Cash flow from financing activities:
Proceeds from investment by member	0	0	10,717
Capital issuance costs			0
Net proceeds from debt issuance	0	0	0
Loans received from and payments made on loans from other Summit Companies	(4,586)	6,647	(10,126)
Payments on long-term debt	(225)	(115)	(8)
Purchase of noncontrolling interests			0
Payments on acquisition-related liabilities	0	0	0
Debt issuance costs	0	0	0
Distributions from partnership	0	0	0
Other	0	(33)	(20)
Net cash provided by (used in) financing activities	(4,811)	6,499	563
Impact of foreign currency on cash	286	(724)	701
Net increase (decrease) in cash	2,115	(7,214)	277
Cash and cash equivalents—beginning of period	7,719	14,933	14,656
Cash and cash equivalents—end of period	$ 9,834	$ 7,719	$ 14,933

Supplementary Data (Unaudited_2

Supplementary Data (Unaudited) - Supplemental Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Condensed Income Statements, Captions [Line Items]
Net revenue	$ 506,259	$ 665,847	$ 552,591	$ 305,950	$ 445,090	$ 625,017	$ 549,235	$ 289,916	$ 2,222,140	$ 2,101,002	$ 1,932,575
Operating income (loss)	59,926	130,881	80,422	(57,671)	28,545	108,167	77,279	(51,525)	213,558	162,466	220,877
Net income	36,397	58,237	37,990	(71,501)	(18,627)	73,992	36,913	(55,948)	61,123	36,330	125,777
Net income (loss) attributable to Summit Inc.	$ 35,671	$ 55,757	$ 36,410	$ (68,772)	$ (19,163)	$ 71,289	$ 35,509	$ (53,729)	59,066	33,906	121,830
Basic earnings (loss) per share attributable to Summit Inc. (USD per share)	$ 0.32	$ 0.50	$ 0.32	$ (0.62)	$ (0.17)	$ 0.64	$ 0.32	$ (0.49)
Diluted earnings (loss) per share attributable to Summit Inc. (USD per share)	$ 0.31	$ 0.48	$ 0.32	$ (0.62)	$ (0.17)	$ 0.64	$ 0.32	$ (0.49)
Summit Materials, LLC
Condensed Income Statements, Captions [Line Items]
Net revenue	$ 506,259	$ 665,847	$ 552,591	$ 305,950	$ 445,090	$ 625,017	$ 549,235	$ 289,916	2,222,140	2,101,002	1,932,575
Operating income (loss)	59,926	130,881	80,422	(57,671)	28,545	108,167	77,279	(51,525)	213,558	162,466	220,877
Net income	$ 41,461	$ 85,199	$ 53,501	$ (91,564)	$ (4,596)	$ 90,427	$ 46,602	$ (68,596)	88,597	63,837	134,041
Net income (loss) attributable to Summit Inc.									$ 88,597	$ 63,837	$ 134,068