Summit Materials (SUM) 10-Q 10 Aug 15 2015 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	Jun. 27, 2015	Jun. 27, 2015	Jul. 29, 2015
Document Information [Line Items]
Document Type		10-Q
Amendment Flag		false
Document Period End Date		Jun. 27, 2015
Document Fiscal Year Focus		2,015
Document Fiscal Period Focus		Q2
Trading Symbol		SUM
Entity Registrant Name		SUMMIT MATERIALS, INC.
Entity Central Index Key		1,621,563
Current Fiscal Year End Date		--12-26
Entity Filer Category		Non-accelerated Filer
Membership interests description	As of July 29, 2015, 100% of Summit Materials, LLC’s outstanding limited liability company interests were held by Summit Materials Intermediate Holdings, LLC, its sole member and an indirect subsidiary of Summit Materials, Inc.
Common Class A [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding			26,584,738
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding			69,007,297
Summit Materials, LLC [Member]
Document Information [Line Items]
Document Type		10-Q
Amendment Flag		false
Document Period End Date		Jun. 27, 2015
Document Fiscal Year Focus		2,015
Document Fiscal Period Focus		Q2
Entity Registrant Name		SUMMIT MATERIALS, LLC
Entity Central Index Key		1,571,371
Current Fiscal Year End Date		--12-26
Entity Filer Category		Non-accelerated Filer
Membership interests percentage			100.00%

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 27, 2015	Dec. 27, 2014
Current assets:
Cash	$ 12,570	$ 13,215
Accounts receivable, net	164,059	141,302
Costs and estimated earnings in excess of billings	24,721	10,174
Inventories	128,417	111,553
Other current assets	19,853	17,172
Total current assets	349,620	293,416
Property, plant and equipment, less accumulated depreciation, depletion and amortization (June 27, 2015 - $317,293 and December 27, 2014 - $279,375)	985,081	950,601
Goodwill	418,659	419,270
Intangible assets, less accumulated amortization (June 27, 2015 - $4,274 and December 27, 2014 - $3,073)	16,257	17,647
Other assets	45,875	48,843
Total assets	1,815,492	1,729,777
Current liabilities:
Current portion of debt	71,275	5,275
Current portion of acquisition-related liabilities	22,395	18,402
Accounts payable	90,822	78,854
Accrued expenses	90,778	101,496
Billings in excess of costs and estimated earnings	8,341	8,958
Total current liabilities	283,611	212,985
Long-term debt	755,972	1,059,642
Acquisition-related liabilities	42,869	42,736
Other noncurrent liabilities	114,153	93,691
Total liabilities	$ 1,196,605	$ 1,409,054
Commitments and contingencies
Redeemable noncontrolling interest		$ 33,740
Stockholders' Equity/Partners' Interest:
Accumulated deficit	$ (10,356)
Accumulated other comprehensive loss	14
Partners' interest		285,685
Additional paid-in capital	457,767
Stockholders' equity/partners' interest:	448,381	285,685
Total liabilities, redeemable noncontrolling interest and member's interest	1,815,492	1,729,777
Total stockholders' equity/partners' interest	618,887	286,983
Common Class A [Member]
Stockholders' Equity/Partners' Interest:
Common stock	266
Total stockholders' equity/partners' interest	266
Common Class B [Member]
Stockholders' Equity/Partners' Interest:
Common stock	690
Total stockholders' equity/partners' interest	690
Summit Materials, LLC [Member]
Current assets:
Cash	12,570	13,215
Accounts receivable, net	164,059	141,302
Costs and estimated earnings in excess of billings	24,721	10,174
Inventories	128,417	111,553
Other current assets	19,853	17,172
Total current assets	349,620	293,416
Property, plant and equipment, less accumulated depreciation, depletion and amortization (June 27, 2015 - $317,293 and December 27, 2014 - $279,375)	985,081	950,601
Goodwill	418,659	419,270
Intangible assets, less accumulated amortization (June 27, 2015 - $4,274 and December 27, 2014 - $3,073)	16,257	17,647
Other assets	45,875	48,843
Total assets	1,815,492	1,729,777
Current liabilities:
Current portion of debt	71,275	5,275
Current portion of acquisition-related liabilities	19,895	18,402
Payable due to Summit Inc.	4,585
Accounts payable	90,822	78,854
Accrued expenses	90,778	101,496
Billings in excess of costs and estimated earnings	8,341	8,958
Total current liabilities	285,696	212,985
Long-term debt	755,972	1,059,642
Acquisition-related liabilities	34,502	42,736
Other noncurrent liabilities	114,153	93,691
Total liabilities	$ 1,190,323	$ 1,409,054
Commitments and contingencies
Redeemable noncontrolling interest		$ 33,740
Member's interest:
Member's equity	$ 971,943	518,647
Stockholders' Equity/Partners' Interest:
Accumulated deficit	(327,212)	(217,416)
Accumulated other comprehensive loss	(20,781)	(15,546)
Member's interest	623,950	285,685
Noncontrolling interest	1,219	1,298
Total member's interest	625,169	286,983
Total liabilities, redeemable noncontrolling interest and member's interest	1,815,492	1,729,777
Noncontrolling interest in consolidated subsidiaries	1,219	$ 1,298
Summit Materials, INC [Member]
Stockholders' Equity/Partners' Interest:
Noncontrolling interest in Summit Materials, Inc.	$ 169,287

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 27, 2015	Dec. 27, 2014
Property, plant and equipment, accumulated depreciation, depletion and amortization	$ 317,293	$ 279,375
Intangible assets, accumulated amortization	$ 4,274	3,073
Common Class A [Member]
Common stock, par value	$ 0.01
Common stock, shares authorized	1,000,000,000
Common stock, shares issued	26,584,738
Common stock, shares outstanding	26,584,738
Common Class B [Member]
Common stock, par value	$ 0.01
Common stock, shares authorized	250,000,000
Common stock, shares issued	69,007,297
Common stock, shares outstanding	69,007,297
Summit Materials, LLC [Member]
Property, plant and equipment, accumulated depreciation, depletion and amortization	$ 317,293	279,375
Intangible assets, accumulated amortization	$ 4,274	$ 3,073

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2015	Jun. 28, 2014	Jun. 27, 2015	Jun. 28, 2014
Revenue:
Product	$ 261,270	$ 221,323	$ 410,190	$ 321,491
Service	67,739	71,087	93,958	106,938
Net revenue	329,009	292,410	504,148	428,429
Delivery and subcontract revenue	35,934	31,885	54,782	46,957
Total revenue	364,943	324,295	558,930	475,386
Cost of revenue (excluding items shown separately below):
Product	163,632	150,137	283,423	234,614
Service	49,604	49,740	69,234	78,866
Net cost of revenue	213,236	199,877	352,657	313,480
Delivery and subcontract cost	35,934	31,885	54,782	46,957
Total cost of revenue	249,170	231,762	407,439	360,437
General and administrative expenses	39,711	34,867	106,945	70,355
Depreciation, depletion, amortization and accretion	27,386	21,339	53,512	40,695
Transaction costs	6,376	2,405	7,740	4,996
Operating income (loss)	42,300	33,922	(16,706)	(1,097)
Other expense (income), net	102	(697)	493	(891)
Loss on debt financings	30,873		31,672
Interest expense	17,395	21,651	41,504	40,470
(Loss) income from continuing operations before taxes	(6,070)	12,968	(90,375)	(40,676)
Income tax benefit	(5,345)	(864)	(9,813)	(1,460)
(Loss) income from continuing operations	(725)	13,832	(80,562)	(39,216)
Income from discontinued operations	(758)	(369)	(758)	(349)
Net income (loss)	$ 33	14,201	$ (79,804)	(38,867)
Net loss per share of Class A common stock:
Basic	$ (0.01)		$ (0.39)
Diluted	$ (0.01)		$ (0.40)
Net income (loss)	$ (205)		$ (10,356)
Weighted average shares of Class A common stock:
Diluted	26,584,738		28,410,890
Summit Materials, LLC [Member]
Revenue:
Product	$ 261,270	221,323	$ 410,190	321,491
Service	67,739	71,087	93,958	106,938
Net revenue	329,009	292,410	504,148	428,429
Delivery and subcontract revenue	35,934	31,885	54,782	46,957
Total revenue	364,943	324,295	558,930	475,386
Cost of revenue (excluding items shown separately below):
Product	163,632	150,137	283,423	234,614
Service	49,604	49,740	69,234	78,866
Net cost of revenue	213,236	199,877	352,657	313,480
Delivery and subcontract cost	35,934	31,885	54,782	46,957
Total cost of revenue	249,170	231,762	407,439	360,437
General and administrative expenses	39,711	34,867	106,945	70,355
Depreciation, depletion, amortization and accretion	27,386	21,339	53,512	40,695
Transaction costs	6,376	2,405	7,740	4,996
Operating income (loss)	42,300	33,922	(16,706)	(1,097)
Other expense (income), net	102	(697)	493	(891)
Loss on debt financings	30,873		31,672
Interest expense	17,104	21,651	41,213	40,470
(Loss) income from continuing operations before taxes	(5,779)	12,968	(90,084)	(40,676)
Income tax benefit	(5,345)	(864)	(9,813)	(1,460)
(Loss) income from continuing operations	(434)	13,832	(80,271)	(39,216)
Income from discontinued operations	(758)	(369)	(758)	(349)
Net income (loss)	324	14,201	(79,513)	(38,867)
Net income (loss) attributable to noncontrolling interest	13	1,946	(1,969)	(569)
Net loss per share of Class A common stock:
Net income (loss)	311	12,255	(77,544)	(38,298)
Summit Holdings [Member]
Net loss per share of Class A common stock:
Net income (loss)	$ (225)	$ (12,255)	$ 67,479	$ 38,298
Common Class A [Member]
Net loss per share of Class A common stock:
Basic	$ (0.01)		$ (0.39)
Diluted	$ (0.01)		$ (0.40)
Weighted average shares of Class A common stock:
Basic	26,584,738		26,584,738
Diluted	26,584,738		28,410,890

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2015	Jun. 28, 2014	Jun. 27, 2015	Jun. 28, 2014
Net income (loss)	$ 33	$ 14,201	$ (79,804)	$ (38,867)
Other comprehensive (loss) income:
Postretirement curtailment adjustment				(1,346)
Postretirement liability adjustment				2,164
Foreign currency translation adjustment	1,064		(5,235)
Other comprehensive income (loss)	1,064		(5,235)	818
Comprehensive income (loss)	1,097	14,201	(85,039)	(38,049)
Comprehensive income (loss) attributable to Summit Materials, Inc. and Summit Materials, LLC	859		(10,342)
Summit Materials, LLC [Member]
Net income (loss)	324	14,201	(79,513)	(38,867)
Other comprehensive (loss) income:
Postretirement curtailment adjustment				(1,346)
Postretirement liability adjustment				2,164
Foreign currency translation adjustment	1,064		(5,235)
Other comprehensive income (loss)	1,064		(5,235)	818
Comprehensive income (loss)	1,388	14,201	(84,748)	(38,049)
Less comprehensive income (loss) attributable to the noncontrolling interest	13	1,946	(1,969)	(324)
Comprehensive income (loss) attributable to Summit Materials, Inc. and Summit Materials, LLC	1,375	12,255	(82,779)	(37,725)
Summit Holdings [Member]
Other comprehensive (loss) income:
Comprehensive income (loss) attributable to Summit Materials, Inc. and Summit Materials, LLC	$ 225	$ 12,255	$ (72,728)	$ (37,725)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 27, 2015	Jun. 28, 2014
Cash flow from operating activities:
Net loss	$ (79,804)	$ (38,867)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, depletion, amortization and accretion	57,131	43,766
Share-based compensation expense	17,020	1,138
Deferred income tax expense (benefit)	23	(525)
Net gain on asset disposals	(3,487)	(76)
Net gain on debt financings	(6,926)
Other	1,185	559
(Increase) decrease in operating assets, net of acquisitions:
Accounts receivable, net	(21,535)	(28,917)
Inventories	(16,555)	(17,820)
Costs and estimated earnings in excess of billings	(14,505)	(10,246)
Other current assets	(2,779)	(2,128)
Other assets	53	2,214
Increase (decrease) in operating liabilities, net of acquisitions:
Accounts payable	3,105	3,589
Accrued expenses	(11,021)	8,511
Billings in excess of costs and estimated earnings	(875)	(4,361)
Other liabilities	(1,114)	(2,717)
Net cash used in operating activities	(80,084)	(45,880)
Cash flow from investing activities:
Acquisitions, net of cash acquired	(15,863)	(234,870)
Purchases of property, plant and equipment	(43,379)	(49,260)
Proceeds from the sale of property, plant and equipment	6,039	5,985
Other	610	757
Net cash used for investing activities	(52,593)	(277,388)
Cash flow from financing activities:
Proceeds from initial public offering	460,000
Capital issuance costs	(36,398)
Capital contributions by partners		24,350
Proceeds from debt issuances	242,000	424,750
Debt issuance costs	(5,130)	(6,354)
Payments on debt	(469,628)	(109,246)
Purchase of noncontrolling interest in consolidated subsidiary	(35,000)
Payments on acquisition-related liabilities	(11,970)	(4,259)
Distributions from partnership	(11,842)
Other		(88)
Net cash provided by (used for) financing activities	132,032	329,153
Net (decrease) increase in cash	(645)	5,885
Cash - beginning of period	13,215	18,184
Cash - end of period	12,570	24,069
Summit Materials, LLC [Member]
Cash flow from operating activities:
Net loss	(79,513)	(38,867)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, depletion, amortization and accretion	56,840	43,766
Share-based compensation expense	17,020	1,138
Deferred income tax expense (benefit)	23	(525)
Net gain on asset disposals	(3,487)	(76)
Net gain on debt financings	(6,926)
Other	1,185	559
(Increase) decrease in operating assets, net of acquisitions:
Accounts receivable, net	(21,535)	(28,917)
Inventories	(16,555)	(17,820)
Costs and estimated earnings in excess of billings	(14,505)	(10,246)
Other current assets	(2,779)	(2,128)
Other assets	53	2,214
Increase (decrease) in operating liabilities, net of acquisitions:
Accounts payable	3,105	3,589
Accrued expenses	(11,021)	8,511
Billings in excess of costs and estimated earnings	(875)	(4,361)
Other liabilities	(1,114)	(2,717)
Net cash used in operating activities	(80,084)	(45,880)
Cash flow from investing activities:
Acquisitions, net of cash acquired	(15,863)	(234,870)
Purchases of property, plant and equipment	(43,379)	(49,260)
Proceeds from the sale of property, plant and equipment	6,039	5,985
Other	610	757
Net cash used for investing activities	(52,593)	(277,388)
Cash flow from financing activities:
Capital contributions by member	397,975	24,350
Capital issuance costs	(9,373)
Proceeds from debt issuances	242,000	424,750
Debt issuance costs	(5,130)	(6,354)
Payments on debt	(469,628)	(109,246)
Payments on acquisition-related liabilities	(11,970)	(4,259)
Distributions from partnership	(11,842)
Other		(88)
Net cash provided by (used for) financing activities	132,032	329,153
Net (decrease) increase in cash	(645)	5,885
Cash - beginning of period	13,215	14,917
Cash - end of period	$ 12,570	$ 20,802

Consolidated Statements of Chan

Consolidated Statements of Changes in Redeemable Noncontrolling Interest and Stockholders' Equity /Member's Interest - USD ($) $ in Thousands	Total	Common Class A [Member]	Common Class B [Member]	Noncontrolling Interest [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss (AOCI) [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]Common Class A [Member]	Additional Paid-in Capital [Member]Common Class B [Member]	Redeemable Noncontrolling Interest [Member]	Summit Materials, LLC [Member]	Summit Materials, LLC [Member]Noncontrolling Interest [Member]	Summit Materials, LLC [Member]Accumulated Deficit [Member]	Summit Materials, LLC [Member]Accumulated Other Comprehensive Loss (AOCI) [Member]	Summit Materials, LLC [Member]Redeemable Noncontrolling Interest [Member]	Summit Materials, LLC [Member]Members Equity [Member]	Summit Materials, LLC [Member]Parent Including Portion Attributable to Non Redeemable Noncontrolling Interest [Member]	Summit Holdings [Member]Partners' Interest [Member]
Beginning Balance at Dec. 28, 2013	$ 286,817									$ 24,767		$ 1,211			$ 24,767			$ 285,606
Beginning Balance at Dec. 28, 2013												1,211	$ (198,511)	$ (6,045)		$ 486,896	$ 283,551
Contributed capital, Summit Materials, Inc	24,350																	24,350
Contributed capital, Summit Materials, LLC																24,350	24,350
Accretion/ redemption value adjustment	(2,404)									2,404			(2,404)		2,404		(2,404)	(2,404)
Net (loss) income	(38,867)									(591)	$ (38,867)	22	(38,298)		(591)		(38,276)	(38,298)
Other comprehensive income (loss)	818									245	818			573	245		573	573
Repurchase of member's interest	87															87	87	87
Share-based compensation	1,138															1,138	1,138	1,138
Ending Balance at Jun. 28, 2014	272,111											1,233						270,878
Ending Balance at Jun. 28, 2014												1,233	(239,213)	(5,472)		512,297	268,845
Ending Balance at Jun. 28, 2014										26,825					26,825
Beginning Balance at Dec. 27, 2014	33,740									33,740	33,740				33,740
Beginning Balance at Dec. 27, 2014											286,983	1,298	(217,416)	(15,546)		518,647	286,983
Beginning Balance at Dec. 27, 2014	286,983											1,298						285,685
Accretion/ redemption value adjustment	(32,252)									32,252								(32,252)
Net (loss) income	(41,415)									(1,890)		(77)						(41,338)
Other comprehensive income (loss)	(5,249)																	(5,249)
Share-based compensation	424																	424
Ending Balance at Mar. 11, 2015	208,491											1,221						207,270
Ending Balance at Mar. 11, 2015										64,102
Recording of noncontrolling interest upon reorganization	(958)
Beginning Balance at Dec. 27, 2014	33,740									33,740	33,740				33,740
Beginning Balance at Dec. 27, 2014											286,983	1,298	(217,416)	(15,546)		518,647	286,983
Beginning Balance at Dec. 27, 2014	286,983											1,298						285,685
Contributed capital, Summit Materials, LLC																452,703	452,703
Accretion/ redemption value adjustment													(32,252)		(31,850)		(32,252)
Net (loss) income	(79,804)										(79,513)	(79)	(77,544)		$ (1,890)		(77,623)
Other comprehensive income (loss)	(5,235)										(5,235)			(5,235)			(5,235)
Share-based compensation																17,020	17,020
Distributions from partnership																(16,427)	(16,427)
Ending Balance at Jun. 27, 2015	618,887	$ 266	$ 690	$ 169,287	$ (10,356)	$ 14	$ 457,767					1,219
Ending Balance at Jun. 27, 2015											625,169	1,219	(327,212)	(20,781)		971,943	625,169
Ending Balance, Shares at Jun. 27, 2015		26,584,738	69,007,297
Issuance of common stock, Shares		25,555,555
Recording of noncontrolling interest upon reorganization				207,270														(207,270)
Beginning Balance at Mar. 11, 2015	208,491											1,221						$ 207,270
Net (loss) income	(36,499)			(26,141)	(10,356)							(2)
Other comprehensive income (loss)	14					14
Share repurchase, Shares			(100)
Purchase of redeemable noncontrolling interest	18,525	$ 10					18,515			$ 64,102
Purchase of redeemable noncontrolling interest, Shares		1,029,183
Share-based compensation	16,596						16,596
Distributions from partnership	(11,842)			(11,842)
Ending Balance at Jun. 27, 2015	618,887	$ 266	$ 690	$ 169,287	$ (10,356)	$ 14	$ 457,767					1,219
Ending Balance at Jun. 27, 2015											$ 625,169	$ 1,219	$ (327,212)	$ (20,781)		$ 971,943	$ 625,169
Ending Balance, Shares at Jun. 27, 2015		26,584,738	69,007,297
Issuance of common stock, Values	$ 423,602	$ 256	$ 690					$ 423,346	$ (690)
Issuance of common stock, Shares		25,555,555	69,007,397

Summary of Organization and Sig

Summary of Organization and Significant Accounting Policies	6 Months Ended
	Jun. 27, 2015
Summary of Organization and Significant Accounting Policies	1. SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES Summit Materials, Inc. (“Summit Inc.” 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-mixed concrete, asphalt paving mix and concrete products and owns and operates quarries, sand and gravel pits, a cement plant, cement distribution terminals, ready-mixed concrete plants, asphalt plants and landfill sites. It is also engaged in paving and related services. The Company is organized by geographic region and has three operating segments, which are also its reporting segments: the West; Central; and East regions. Substantially all of the Company’s 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 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 initial public offering, Summit Inc. became a holding corporation operating and controlling all of the business and affairs of Summit Holdings and its subsidiaries and, through Summit Holdings, conducts its business. Certain investment funds affiliated with Blackstone Capital Partners V L.P. and Silverhawk Summit, L.P. (collectively, the “Sponsors”), as well as Summit Inc., are the primary owners of Summit Holdings. Initial Public Offering 1 2 Basis of Presentation Management believes that these consolidated interim financial statements include all adjustments, normal and recurring in nature, that are necessary to present fairly the financial position of the Company as of June 27, 2015, the results of operations for the three and six months ended June 27, 2015 and June 28, 2014 and cash flows for the six months ended June 27, 2015 and June 28, 2014. All significant intercompany balances and transactions have been eliminated. 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 occurs approximately once every seven years and will occur in 2015. The additional week in the 53-week year will be included in the fourth quarter. The consolidated financial statements of the Company include the accounts of Summit Inc. and its subsidiaries, including noncontrolling interests. As a result of the Reorganization, Summit Holdings became a variable interest entity. Summit Inc. is the primary beneficiary of Summit Holdings as a result of its 100% voting power and control over Summit Holdings and its obligation to absorb losses and its right to receive benefits of Summit Holdings and thus consolidates Summit Holdings in its consolidated financial statements with a corresponding noncontrolling interest elimination of 72.2%. Noncontrolling interests in consolidated subsidiaries represent a 20% ownership in Ohio Valley Asphalt, LLC and, prior to the IPO and concurrent purchase of the noncontrolling interests of Continental Cement, a 30% redeemable ownership in Continental Cement. Use of Estimates Business and Credit Concentrations— Earnings per Share— Fair Value Measurements— June 27, December 27, 2015 2014 Current portion of acquisition-related liabilities: Current portion of contingent consideration $ 4,486 $ 2,375 Acquisition-related liabilities: Contingent consideration $ 4,193 $ 5,379 The fair values are based on unobservable, or Level 3, inputs, including projected probability-weighted cash payments and an 11.0% 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. There were no material valuation adjustments to contingent consideration obligations in the three or six months ended June 27, 2015 or June 28, 2014. Financial Instruments June 27, 2015 December 27, 2014 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt (1) $ 780,155 $ 827,247 $ 1,101,873 $ 1,064,917 Level 3 Current portion of deferred consideration and noncompete obligations (2) 17,909 17,909 16,027 16,027 Long term portion of deferred consideration and noncompete obligations (3) 38,676 38,676 37,357 37,357 (1) $5.3 million included in current portion of debt as of June 27, 2015 and December 27, 2014. Excludes $66.0 million outstanding on the revolving credit facility as of June 27, 2015. (2) Included in current portion of acquisition-related liabilities on the balance sheet. (3) Included in acquisition-related liabilities on the balance sheet. 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. Redeemable Noncontrolling Interest New Accounting Standards — Simplifying the Presentation of Debt Issuance Costs In April 2015, the FASB issued a new accounting standard, ASU 2015-04, Practical Expedient for the Measurement Date of an Employer’s Defined Benefit Obligation and Plan Assets In May 2014, the FASB issued a new accounting standard to improve and converge the financial reporting requirements for revenue from contracts with customers. ASU No. 2014-09, Revenue from Contracts with Customers Reclassifications
Summit Materials, LLC [Member]
Summary of Organization and Significant Accounting Policies	1. SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES Summit Materials, LLC (“Summit LLC”) is a vertically integrated, construction materials company. Through its subsidiaries, it is engaged in the production and sale of aggregates, cement, ready-mixed concrete, asphalt paving mix and concrete products. Summit LLC, through its subsidiaries (collectively, the “Company”), owns and operates quarries, sand and gravel pits, a cement plant, cement distribution terminals, ready-mixed concrete plants, asphalt plants and landfill sites. It is also engaged in paving and related services. The Company is organized by geographic region and has three operating segments, which are also its reporting segments: the West; Central; and East regions. Substantially all of the Company’s 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 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 major indirect owners are certain investment funds affiliated with Blackstone Capital Partners V L.P. and Silverhawk Summit, L.P. and Summit Materials, Inc. (“Summit Inc.”). Summit Inc. was formed as a Delaware corporation on September 23, 2014 to be a holding company. Its sole 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 (“IPO”), 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. commenced operations on March 11, 2015 upon the pricing of the initial public offering of its Class A common stock (“IPO”). Summit Inc. raised $433.0 million, net of underwriting discounts, through the issuance of 25,555,555 shares of Class A common stock at a public offering price of $18.00 per share. Summit Inc. used the offering proceeds to purchase a number of newly-issued Class A Units (“LP Units”) from Summit Holdings equal to the number of shares of Class A common stock issued to the public. Summit Inc. caused Summit Holdings to use these proceeds: (i) to redeem $288.2 million in aggregate principal amount of outstanding 10 1 2 Basis of Presentation 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 occurs approximately once every seven years and will occur in 2015. The additional week in the 53-week year will be included in the fourth quarter. The consolidated financial statements of the Company include the accounts of Summit LLC and its subsidiaries, including noncontrolling interests. All significant intercompany balances and transactions have been eliminated. Noncontrolling interests in consolidated subsidiaries represent a 20% ownership in Ohio Valley Asphalt, LLC and, prior to the IPO and concurrent purchase of the noncontrolling interests of Continental Cement Company, L.L.C. (“Continental Cement”), a 30% redeemable ownership in Continental Cement. Use of Estimates Business and Credit Concentrations— Fair Value Measurements— June 27, December 27, 2015 2014 Current portion of acquisition-related liabilities: Current portion of contingent consideration $ 4,486 $ 2,375 Acquisition- related liabilities: Contingent consideration $ 4,193 $ 5,379 The fair values are based on unobservable, or Level 3, inputs, including projected probability-weighted cash payments and an 11.0% 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. There were no material valuation adjustments to contingent consideration obligations in the three or six months ended June 27, 2015 or June 28, 2014. Financial Instruments June 27, 2015 December 27, 2014 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt (1) $ 780,155 $ 827,247 $ 1,101,873 $ 1,064,917 Level 3 Current portion of deferred consideration and noncompete obligations (2) 15,409 15,409 16,027 16,027 Long term portion of deferred consideration and noncompete obligations (3) 30,309 30,309 37,357 37,357 (1) $5.3 million included in current portion of debt as of June 27, 2015 and December 27, 2014. Excludes $66.0 million outstanding on the revolving credit facility as of June 27, 2015. (2) Included in current portion of acquisition-related liabilities on the balance sheet. (3) Included in acquisition-related liabilities on the balance sheet. 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. Redeemable Noncontrolling Interest New Accounting Standards — Simplifying the Presentation of Debt Issuance Costs In April 2015, the FASB issued a new accounting standard, ASU 2015-04, Practical Expedient for the Measurement Date of an Employer’s Defined Benefit Obligation and Plan Assets, In May 2014, the FASB issued a new accounting standard to improve and converge the financial reporting requirements for revenue from contracts with customers. ASU No. 2014-09, Revenue from Contracts with Customers Reclassifications

Reorganization

Reorganization	6 Months Ended
	Jun. 27, 2015
Reorganization	2. REORGANIZATION Prior to the IPO and Reorganization, the capital structure of Summit Holdings consisted of six different classes of limited partnership interests (Class A-1, Class A-2, Class B-1, Class C, Class D-1 and Class D-2), each of which was subject to unique distribution rights. There were no outstanding Class A-2 interests. In connection with the IPO and the Reorganization, the limited partnership agreement of Summit Holdings was amended and restated to, among other things, modify its capital structure by creating a single new class of units (the “LP Units”), referred to as the “Reclassification.” Immediately following the Reclassification, 69,007,297 LP Units were outstanding. In addition, in substitution for part of the economic benefit of the Class C and Class D interests that was not reflected in the conversion of such interests to LP Units, warrants were issued to holders of Class C interests to purchase an aggregate of 160,333 shares of Class A common stock, and options were issued to holders of Class D interests to purchase an aggregate of 4,358,842 shares of Class A common stock (“leverage restoration options”). In each case, the exercise price of such warrants and leverage restoration options was the IPO price of $18.00 per share. In conjunction with the Reclassification of the equity-based awards, the Company recognized a $14.5 million modification charge in general and administrative costs in the three months ended March 28, 2015. The leverage restoration options were granted under the Summit Materials, Inc. 2015 Omnibus Incentive Plan (the “Omnibus Incentive Plan”). The leverage restoration options that correlate to time-vesting interests vest over four years, beginning on the Reclassification date and the leverage restoration options that correlate to performance-vesting interests vest only when both the relevant return multiple is achieved and a four year time-vesting condition is satisfied. The time-based vesting condition for both the time-vesting and performance-vesting interests will be satisfied with respect to 25% of the performance-vesting options on each of the first four anniversaries of the Reclassification date, subject to the employee’s continued employment through the applicable vesting date. The number of leverage restoration options granted in respect of each Class D interest was based on the IPO price. The Company also granted 240,000 options to purchase shares of Class A common stock under the Omnibus Incentive Plan to certain employees some of whom had not previously been granted equity-based interests. These stock options have an exercise price of $18.00 per share, the IPO price, and are subject to a time-based vesting condition that will be satisfied with respect to 25% of the award on each of the first four anniversaries of the grant date, subject to the employee’s continued employment through the applicable vesting date.
Summit Materials, LLC [Member]
Reorganization	2. REORGANIZATION Prior to the IPO and Reorganization, the capital structure of Summit Holdings consisted of six different classes of limited partnership interests (Class A-1, Class A-2, Class B-1, Class C, Class D-1 and Class D-2), each of which was subject to unique distribution rights. There were no outstanding Class A-2 interests. In connection with the IPO and the Reorganization, the limited partnership agreement of Summit Holdings was amended and restated to, among other things, modify its capital structure by creating a single new class of units (the “LP Units”), referred to as the “Reclassification.” Immediately following the Reclassification, 69,007,297 LP Units were outstanding. In addition, in substitution for part of the economic benefit of the Class C and Class D interests that was not reflected in the conversion of such interests to LP Units, warrants were issued to holders of Class C interests to purchase an aggregate of 160,333 shares of Class A common stock, and options were issued to holders of Class D interests to purchase an aggregate of 4,358,842 shares of Class A common stock (“leverage restoration options”). In each case, the exercise price of such warrants and leverage restoration options was the IPO price of $18.00 per share. In conjunction with the Reclassification of the equity-based awards, the Company recognized $14.5 million modification charge in general and administrative costs in the three months ended March 28, 2015.

Accounts Receivable, Net

Accounts Receivable, Net	6 Months Ended
	Jun. 27, 2015
Accounts Receivable, Net	3. ACCOUNTS RECEIVABLE, NET Accounts receivable, net consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Trade accounts receivable $ 154,678 $ 131,060 Retention receivables 11,119 12,053 Receivables from related parties 629 333 Accounts receivable 166,426 143,446 Less: Allowance for doubtful accounts (2,367 ) (2,144 ) Accounts receivable, net $ 164,059 $ 141,302 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 expected to be billed and collected within one year.
Summit Materials, LLC [Member]
Accounts Receivable, Net	3. ACCOUNTS RECEIVABLE, NET Accounts receivable, net consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Trade accounts receivable $ 154,678 $ 131,060 Retention receivables 11,119 12,053 Receivables from related parties 629 333 Accounts receivable 166,426 143,446 Less: Allowance for doubtful accounts (2,367 ) (2,144 ) Accounts receivable, net $ 164,059 $ 141,302 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 expected to be billed and collected within one year.

Inventories

Inventories	6 Months Ended
	Jun. 27, 2015
Inventories	4. INVENTORIES Inventories consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Aggregate stockpiles $ 91,036 $ 88,211 Finished goods 16,791 8,826 Work in process 1,882 1,801 Raw materials 18,708 12,715 Total $ 128,417 $ 111,553
Summit Materials, LLC [Member]
Inventories	4. INVENTORIES Inventories consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Aggregate stockpiles $ 91,036 $ 88,211 Finished goods 16,791 8,826 Work in process 1,882 1,801 Raw materials 18,708 12,715 Total $ 128,417 $ 111,553

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 27, 2015
Accrued Expenses	5. ACCRUED EXPENSES Accrued expenses consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Interest $ 19,908 $ 32,475 Payroll and benefits 17,733 20,326 Capital lease obligations 18,400 17,530 Insurance 11,780 11,402 Non-income taxes 6,464 5,520 Professional fees 5,142 3,299 Other (1) 11,351 10,944 Total $ 90,778 $ 101,496 (1) Consists primarily of subcontractor and working capital settlement accruals.
Summit Materials, LLC [Member]
Accrued Expenses	5. ACCRUED EXPENSES Accrued expenses consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Interest $ 19,908 $ 32,475 Payroll and benefits 17,733 20,326 Capital lease obligations 18,400 17,530 Insurance 11,780 11,402 Non-income taxes 6,464 5,520 Professional fees 5,142 3,299 Other (1) 11,351 10,944 Total $ 90,778 $ 101,496 (1) Consists primarily of subcontractor and working capital settlement accruals.

Debt

Debt	6 Months Ended
	Jun. 27, 2015
Debt	6. DEBT Debt consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Revolving credit facility $ 66,000 $ — Long-term debt: $336.8 million senior notes, including a $12.9 million net premium at June 27, 2015 and $625.0 million senior notes, including a $26.5 million net premium at December 27, 2014 349,701 651,548 $413.6 million term loan, net of $2.1 million discount at June 27, 2015 and $415.7 million term loan, net of $2.3 million discount at December 27, 2014 411,546 413,369 Total 761,247 1,064,917 Current portion of long-term debt 5,275 5,275 Long-term debt $ 755,972 $ 1,059,642 The contractual payments of long-term debt, including current maturities, for the five years subsequent to June 27, 2015, are as follows: 2015 (six months) $ 3,165 2016 4,220 2017 4,220 2018 3,165 2019 398,790 2020 336,800 Total 750,360 Plus: Original issue net premium 10,887 Total debt $ 761,247 2020 Notes In April 2015, using proceeds from the IPO, $288.2 million aggregate principal amount of the outstanding 2020 Notes were redeemed at a price equal to par plus an applicable premium. As a result of the redemption, a net charge of $31.3 million was recognized, which was composed of $38.2 million for the applicable prepayment premium and $4.7 million for the write-off of deferred financing fees, which was partially offset by an $11.6 million net benefit from the write-off the original issuance premium and discount. On September 8, 2014 and January 17, 2014, the Issuers issued an additional $115.0 million and $260.0 million, respectively, aggregate principal amount of 2020 Notes (the “Additional Notes”), receiving proceeds of $409.3 million, before payment of fees and expenses and including an aggregate $34.3 million premium. The proceeds from the sale of the Additional Notes were used for the purchases of acquisitions, to make payments on the revolving credit facility and for general corporate purposes. The Additional Notes are treated as a single series with the $250.0 million of 2020 Notes (the “Existing Notes”) and have substantially the same terms as those of the Existing Notes. The Additional Notes and the Existing Notes are treated as one class under the Indenture. Senior Secured Credit Facilities On March 11, 2015, Summit LLC entered into Amendment No. 3 to the credit agreement governing the Senior Secured Credit Facilities, which became effective on March 17, 2015 upon the consummation of the IPO. The amendment: (i) increased the size of the revolving credit facility from $150.0 million to $235.0 million; (ii) extended the maturity date of the revolving credit facility to March 11, 2020; (iii) amended certain covenants; and (iv) permits periodic tax distributions as contemplated in a tax receivable agreement, dated as of March 11, 2015, with Summit Holdings. As a result of this amendment, $0.4 million of financing fees were charged to earnings in the six months ended June 27, 2015. 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 2.5% 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 3.5% for LIBOR rate loans. The interest rate in effect at June 27, 2015 was 3.6%. There were $66.0 million of outstanding borrowings under the revolving credit facility as of June 27, 2015, leaving remaining borrowing capacity of $144.8 million, which is net of $24.2 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 must adhere to certain financial covenants related to its Consolidated First Lien Net Leverage Ratio and Interest Coverage Ratio, as each such term is defined in the Senior Secured Credit Facilities. The Consolidated First Lien Net Leverage Ratio, reported each quarter, should be no greater than 4.5:1.0. The interest coverage ratio must be at least 1.85:1.0. As of June 27, 2015 and December 27, 2014, Summit LLC was in compliance with all covenants. Summit LLC’s wholly-owned domestic subsidiary companies, subject to certain exclusions and exceptions, are named as subsidiary guarantors of the 2020 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. Interest expense related to debt totaled $14.8 million and $36.8 million for the three and six months ended June 27, 2015, respectively, and $19.3 million and $36.5 million for the three and six months ended June 28, 2014, respectively. The following table presents the activity for the deferred financing fees for the six months ended June 27, 2015 and June 28, 2014: Deferred financing fees Balance — December 27, 2014 $ 17,215 Loan origination fees 5,130 Amortization (1,701 ) Write off of deferred financing fees (5,109 ) Balance — June 27, 2015 $ 15,535 Balance — December 28, 2013 $ 11,485 Loan origination fees 6,309 Amortization (1,544 ) Balance —June 28, 2014 $ 16,250 Other
Summit Materials, LLC [Member]
Debt	6. DEBT Debt consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Revolving credit facility $ 66,000 $ — Long-term debt: $336.8 million senior notes, including a $12.9 million net premium at June 27, 2015 and $625.0 million senior notes, including a $26.5 million net premium at December 27, 2014 349,701 651,548 $413.6 million term loan, net of $2.1 million discount at June 27, 2015 and $415.7 million term loan, net of $2.3 million discount at December 27, 2014 411,546 413,369 Total 761,247 1,064,917 Current portion of long-term debt 5,275 5,275 Long-term debt $ 755,972 $ 1,059,642 The contractual payments of long-term debt, including current maturities, for the five years subsequent to June 27, 2015, are as follows: 2015 (six months) $ 3,165 2016 4,220 2017 4,220 2018 3,165 2019 398,790 2020 336,800 Total 750,360 Plus: Original issue net premium 10,887 Total debt $ 761,247 2020 Notes In April 2015, using proceeds from the IPO, $288.2 million aggregate principal amount of the outstanding 2020 Notes were redeemed at a price equal to par plus an applicable premium. As a result of the redemption, a net charge of $31.3 million was recognized, which was composed of $38.2 million for the applicable prepayment premium and $4.7 million for the write-off of deferred financing fees, which was partially offset by an $11.6 million net benefit from the write-off the original issuance premium and discount. On September 8, 2014 and January 17, 2014, the Issuers issued an additional $115.0 million and $260.0 million, respectively, aggregate principal amount of 2020 Notes (the “Additional Notes”), receiving proceeds of $409.3 million, before payment of fees and expenses and including an aggregate $34.3 million premium. The proceeds from the sale of the Additional Notes were used for the purchases of acquisitions, to make payments on the revolving credit facility and for general corporate purposes. The Additional Notes are treated as a single series with the $250.0 million of 2020 Notes (the “Existing Notes”) and have substantially the same terms as those of the Existing Notes. The Additional Notes and the Existing Notes are treated as one class under the Indenture. Senior Secured Credit Facilities On March 11, 2015, the Company entered into Amendment No. 3 to the credit agreement governing the Senior Secured Credit Facilities, which became effective on March 17, 2015 upon the consummation of the IPO. The amendment: (i) increased the size of the revolving credit facility from $150.0 million to $235.0 million; (ii) extended the maturity date of the revolving credit facility to March 11, 2020; (iii) amended certain covenants; and (iv) permits periodic tax distributions as contemplated in a tax receivable agreement, dated as of March 11, 2015, with Summit Holdings. As a result of this amendment, $0.4 million of financing fees were charged to earnings in the six months ended June 27, 2015. 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 2.5% 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 3.5% for LIBOR rate loans. The interest rate in effect at June 27, 2015 was 3.6%. There were $66.0 of outstanding borrowings under the revolving credit facility as of June 27, 2015, leaving remaining borrowing capacity of $144.8 million, which is net of $24.2 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 must adhere to certain financial covenants related to its debt and interest leverage ratios, as defined in the Senior Secured Credit Facilities. The consolidated first lien net leverage ratio, reported each quarter, should be no greater than 4.5:1.0. The interest coverage ratio must be at least 1.70:1.0 from January 1, 2013 through December 31, 2014 and 1.85:1.0 thereafter. As of March 27, 2015 and December 27, 2014, the Company was in compliance with all covenants. Summit LLC’s wholly-owned domestic subsidiary companies are subject to certain exclusions and exceptions are named as subsidiary guarantors of the 2020 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. Interest expense related to debt totaled $14.8 million and $36.8 million for the three and six months ended June 27, 2015, respectively, and $19.3 million and $36.5 million for the three and six months ended June 28, 2014, respectively. The following table presents the activity for the deferred financing fees for the six months ended June 27, 2015 and June 28, 2014: Deferred financing fees Balance — December 27, 2014 $ 17,215 Loan origination fees 5,130 Amortization (1,701 ) Write off of deferred financing fees (5,109 ) Balance — June 27, 2015 $ 15,535 Balance — December 28, 2013 $ 11,485 Loan origination fees 6,309 Amortization (1,544 ) Balance —June 28, 2014 $ 16,250 Other

Income Taxes

Income Taxes	6 Months Ended
	Jun. 27, 2015
Income Taxes	7. 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. 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 subsidiaries are fully reflected in the Company’s accounts. As of June 27, 2015 and December 27, 2014, Summit Inc. and its subsidiaries had not recognized any liabilities for uncertain tax positions. 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 for the three and six months ended June 27, 2015 and June 28, 2014. Summit Inc. In assessing the realizability of deferred tax assets, including the deferred tax assets resulting from the expected taxable loss in 2015, management determined that it was more likely than not that the deferred tax assets will not be realized. 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 and consideration of tax-planning strategies. Considering these factors, a full valuation allowance was recorded for Summit Inc.’s net deferred tax assets as of the IPO date and June 27, 2015, which has resulted in no provision for Summit Inc.’s income taxes in the three and six months ended June 27, 2015. C Corporation Subsidiaries Tax Receivable Agreement Tax Distributions –
Summit Materials, LLC [Member]
Income Taxes	8. INCOME TAXES Summit LLC is a limited liability company and passes its tax attributes for federal and state tax purposes to its parent company and is generally not subject to federal or state income tax. However, certain subsidiary entities file federal and state income tax returns due to their status as C corporations. The provision for income taxes is primarily composed of federal, state and local income taxes for the subsidiary entities that have C corporation status. The effective income tax rate for these entities differs from the statutory federal rate primarily due to (1) tax depletion expense in excess of the expense recorded under U.S. GAAP, (2) state income taxes and the effect of graduated tax rates and (3) certain non-recurring items, such as differences in the treatment of transaction costs, which are often not deductible for tax purposes. As of June 27, 2015 and December 27, 2014, the Company has not recognized any liabilities for uncertain tax positions. 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 for the three or six months ended June 27, 2015 and June 28, 2014. Tax Distributions –

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 27, 2015
Earnings Per Share [Abstract]
Net Loss Per Share	8. NET LOSS PER SHARE Immediately prior to the consummation of the Company’s IPO, the Company did not have outstanding common stock. In conjunction with the IPO, Summit Inc. sold 25,555,555 shares of Class A shares common stock to the public and issued 1,029,183 shares of Class A common stock in conjunction with the purchase of the noncontrolling interest of Continental Cement. The outstanding stock options and warrants granted in connection with the IPO are excluded from the calculations below as they would have an antidilutive effect. The following table reconciles basic to diluted loss per share: June 27, 2015 Three months Six months (in thousands, except per share amounts) ended ended Net loss attributable to Summit Materials, Inc.: Net loss attributable to Summit Inc. $ (205 ) $ (10,356 ) Add: Noncontrolling interest impact of LP Unit conversion (1) — (958 ) Diluted net loss attributable to Summit Inc. $ (205 ) $ (11,314 ) Weighted-average common shares: Weighted average shares of Class A shares outstanding 26,584,738 26,584,738 Basic earnings per share $ (0.01 ) $ (0.39 ) Weighted average shares of Class A shares outstanding 26,584,738 26,584,738 Add: weighted average of LP Units — 1,826,152 Weighted average dilutive shares outstanding 26,584,738 28,410,890 Diluted earnings per share $ (0.01 ) $ (0.40 ) (1) Diluted net loss for the six months ended June 27, 2015 considers the change in ownership percentage from 27.8% to 30.4% as a result of the LP unit conversions. Basic and diluted earnings per share for discontinued operations attributable to Summit Inc. were $0.01 in the three and six months ended June 27, 2015.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 27, 2015
Commitments and Contingencies	9. 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 pending or threatened claims and litigation will not have a material effect on the Company’s consolidated results of operations, financial position or liquidity. The Company’s policy is to record legal fees as incurred. Litigation and Claims During the ordinary course of business, there may be revisions to project costs and conditions that can give rise to change orders on construction contracts. Revisions can also result in claims made against a customer or subcontractor to recover project variances that have not been satisfactorily addressed through change orders with a customer. As of June 27, 2015 and December 27, 2014, the Company had unapproved change orders and claims of $1.4 million ($1.2 million in accounts receivable and $0.2 million in costs and estimated earnings in excess of billings) and $3.9 million ($1.2 million in accounts receivable, $0.5 million in costs and estimated earnings in excess of billings and $2.2 million in other assets), respectively. Environmental Remediation Other
Summit Materials, LLC [Member]
Commitments and Contingencies	9. 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 pending or threatened claims and litigation will not have a material effect on the Company’s consolidated results of operations, financial position or liquidity. The Company’s policy is to record legal fees as incurred. Litigation and Claims During the ordinary course of business, there may be revisions to project costs and conditions that can give rise to change orders on construction contracts. Revisions can also result in claims made against a customer or subcontractor to recover project variances that have not been satisfactorily addressed through change orders with a customer. As of June 27, 2015 and December 27, 2014, the Company had unapproved change orders and claims of $1.4 million ($1.2 million in accounts receivable and $0.2 million in costs and estimated earnings in excess of billings) and $3.9 million ($1.2 million in accounts receivable, $0.5 million in costs and estimated earnings in excess of billings and $2.2 million in other assets), respectively. Environmental Remediation Other

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	6 Months Ended
	Jun. 27, 2015
Supplemental Cash Flow Information	10. SUPPLEMENTAL CASH FLOW INFORMATION Supplemental cash flow information is as follows: Six months ended June 27, June 28, 2015 2014 Cash payments: Interest $ 50,646 $ 25,881 Income taxes 1,257 1,320 Non cash financing activities: Purchase of noncontrolling interest in Continental Cement $ (29,102 ) $ —
Summit Materials, LLC [Member]
Supplemental Cash Flow Information	10. SUPPLEMENTAL CASH FLOW INFORMATION Supplemental cash flow information is as follows: Six months ended June 27, June 28, 2015 2014 Cash payments: Interest $ 50,646 $ 25,881 Income taxes 1,257 1,320 Non cash financing activities: Purchase of noncontrolling interest in Continental Cement $ (64,102 ) $ —

Segment Information

Segment Information	6 Months Ended
	Jun. 27, 2015
Segment Information	11. SEGMENT INFORMATION The Company has three operating segments, which are its reportable segments: the West; Central; and East regions. These segments are consistent with the Company’s management reporting structure. Each region’s operations consist of various activities related to the production, distribution and sale of construction materials, products and the provision of paving and related services. Assets employed by 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 preparing the consolidated financial statements. The following tables display selected financial data for the Company’s reportable segments: Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Revenue: West region $ 208,068 $ 172,236 $ 335,742 $ 267,130 Central region 117,920 109,117 174,529 156,659 East region 38,955 42,942 48,659 51,597 Total revenue $ 364,943 $ 324,295 $ 558,930 $ 475,386 Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Adjusted EBITDA West region $ 39,497 $ 30,750 $ 51,366 $ 32,541 Central region 35,518 28,823 36,228 28,400 East region 9,580 7,932 1,713 (1,406 ) Corporate and other (15,011 ) (11,547 ) (24,698 ) (19,046 ) Total reportable segments and corporate 69,584 55,958 64,609 40,489 Interest expense 17,395 21,651 41,504 40,470 Depreciation, depletion, amortization and accretion 27,386 21,339 53,512 40,695 Initial public offering costs — — 28,296 — Loss on debt financings 30,873 — 31,672 — (Loss) income from continuing operations before taxes $ (6,070 ) $ 12,968 $ (90,375 ) $ (40,676 ) Six months ended June 27, June 28, 2015 2014 Cash paid for capital expenditures: West region $ 18,037 $ 17,924 Central region 15,920 23,372 East region 7,518 5,533 Total reportable segments 41,475 46,829 Corporate and other 1,904 2,431 Total capital expenditures $ 43,379 $ 49,260 Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Depreciation, depletion, amortization and accretion: West region $ 12,634 $ 7,667 $ 24,722 $ 14,414 Central region 11,348 9,504 21,420 18,351 East region 2,835 3,831 6,312 7,288 Total reportable segments 26,817 21,002 52,454 40,053 Corporate and other 569 337 1,058 642 Total depreciation, depletion, amortization and accretion $ 27,386 $ 21,339 $ 53,512 $ 40,695 June 27, December 27, 2015 2014 Total assets: West region $ 824,892 $ 777,981 Central region 726,976 704,134 East region 230,353 221,598 Total reportable segments 1,782,221 1,703,713 Corporate and other 33,271 26,064 Total $ 1,815,492 $ 1,729,777 Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Revenue by product:* Aggregates $ 79,929 $ 59,816 $ 132,266 $ 91,366 Cement 30,177 27,557 41,996 35,264 Ready-mixed concrete 89,309 71,389 159,397 113,769 Asphalt 85,329 74,686 106,243 99,082 Paving and related services 137,330 144,911 181,229 200,768 Other (57,131 ) (54,064 ) (62,201 ) (64,863 ) Total revenue $ 364,943 $ 324,295 $ 558,930 $ 475,386 * Revenue by product includes intercompany and intracompany sales transferred at market value. The elimination of intracompany transactions is included in Other. Revenue from the liquid asphalt terminals is included in asphalt revenue.
Summit Materials, LLC [Member]
Segment Information	11. SEGMENT INFORMATION The Company has three operating segments, which are its reportable segments: the West; Central; and East regions. These segments are consistent with the Company’s management reporting structure. Each region’s operations consist of various activities related to the production, distribution and sale of construction materials, products and the provision of paving and related services. Assets employed by 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 preparing the consolidated financial statements. The following tables display selected financial data for the Company’s reportable segments: Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Revenue: West region $ 208,068 $ 172,236 $ 335,742 $ 267,130 Central region 117,920 109,117 174,529 156,659 East region 38,955 42,942 48,659 51,597 Total revenue $ 364,943 $ 324,295 $ 558,930 $ 475,386 Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Adjusted EBITDA West region $ 39,497 $ 30,750 $ 51,366 $ 32,541 Central region 35,518 28,823 36,228 28,400 East region 9,580 7,932 1,713 (1,406 ) Corporate and other (15,011 ) (11,547 ) (24,698 ) (19,046 ) Total reportable segments and corporate 69,584 55,958 64,609 40,489 Interest expense 17,104 21,651 41,213 40,470 Depreciation, depletion, amortization and accretion 27,386 21,339 53,512 40,695 Initial public offering costs — — 28,296 — Loss on debt financings 30,873 — 31,672 — (Loss) income from continuing operations before taxes $ (5,779 ) $ 12,968 $ (90,084 ) $ (40,676 ) Six months ended June 27, June 28, 2015 2014 Cash paid for capital expenditures: West region $ 18,037 $ 17,924 Central region 15,920 23,372 East region 7,518 5,533 Total reportable segments 41,475 46,829 Corporate and other 1,904 2,431 Total capital expenditures $ 43,379 $ 49,260 Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Depreciation, depletion, amortization and accretion: West region $ 12,634 $ 7,667 $ 24,722 $ 14,414 Central region 11,348 9,504 21,420 18,351 East region 2,835 3,831 6,312 7,288 Total reportable segments 26,817 21,002 52,454 40,053 Corporate and other 569 337 1,058 642 Total depreciation, depletion, amortization and accretion $ 27,386 $ 21,339 $ 53,512 $ 40,695 June 27, December 27, 2015 2014 Total assets: West region $ 824,892 $ 777,981 Central region 726,976 704,134 East region 230,353 221,598 Total reportable segments 1,782,221 1,703,713 Corporate and other 33,271 26,064 Total $ 1,815,492 $ 1,729,777 Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Revenue by product:* Aggregates $ 79,929 $ 59,816 $ 132,266 $ 91,366 Cement 30,177 27,557 41,996 35,264 Ready-mixed concrete 89,309 71,389 159,397 113,769 Asphalt 85,329 74,686 106,243 99,082 Paving and related services 137,330 144,911 181,229 200,768 Other (57,131 ) (54,064 ) (62,201 ) (64,863 ) Total revenue $ 364,943 $ 324,295 $ 558,930 $ 475,386 * Revenue by product includes intercompany and intracompany sales transferred at market value. The elimination of intracompany transactions is included in Other. Revenue from the liquid asphalt terminals is included in asphalt revenue.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 27, 2015
Related Party Transactions	12. RELATED PARTY TRANSACTIONS Under the terms of a transaction and management fee agreement between Summit Holdings and Blackstone Management Partners L.L.C. (“BMP”), whose affiliates include controlling stockholders of the Company, BMP provided monitoring, advisory and consulting services to the Company through March 17, 2015. Under the terms of the agreement, BMP was permitted to assign, and had assigned, a portion of the fees to which it is entitled to Silverhawk Summit, L.P. and to certain other equity investors. The management fee was calculated based on the greater of $300,000 or 2.0% of the Company’s annual consolidated profit, as defined in the agreement, which are included in general and administrative expenses. The Company incurred management fees due to BMP totaling $1.0 million during the period between December 28, 2014 and March 17, 2015 and $1.3 million and $2.3 million in the three and six months ended June 28, 2014, respectively. During these periods, the Company paid immaterial amounts to Silverhawk Summit, L.P. and to other equity investors. Also under the terms of the transaction and management fee agreement, BMP undertook financial and structural analysis, due diligence investigations, corporate strategy and other advisory services and negotiation assistance related to acquisitions for which the Company paid BMP transaction fees equal to 1.0% of the aggregate enterprise value of any acquired entity or, if such transaction was structured as an asset purchase or sale, 1.0% of the consideration paid for or received in respect of the assets acquired or disposed. The Company paid BMP $0.6 million and $2.3 million during the three and six months ended June 28, 2014, respectively. During these periods, the Company paid immaterial amounts to Silverhawk Summit, L.P. and to other equity investors. The acquisition-related fees paid pursuant to this agreement are included in transaction costs. In connection with the IPO, the transaction and management fee agreement with BMP was terminated on March 17, 2015 for a final payment of approximately $13.8 million, $13.4 million was paid to affiliates of Blackstone and the remaining $0.4 million was paid to affiliates of Silverhawk Summit, L.P. and to certain other equity investors. In addition to the transaction and management fees paid to BMP, the Company reimburses BMP for direct expenses incurred, which were not material in the three and six months ended June 27, 2015 and June 28, 2014. On April 16, 2015, the Company entered into an agreement with Lafarge North America Inc. (“Lafarge”) to purchase certain assets, including a cement plant, a quarry and seven cement distribution terminals (the “Davenport Assets”) for a purchase price of $450.0 million cash and a cement distribution terminal in Bettendorf, Iowa. At closing, $370.0 million of the purchase price was due and the remaining $80.0 million is due to the seller no later than December 31, 2015. Summit Holdings entered into a commitment letter dated April 16, 2015, with Blackstone Capital Partners V L.P. (“BCP”) for equity financing up to $90.0 million in the form of a preferred equity interest (the “Equity Commitment Financing”). The proceeds of the Equity Commitment Financing would be used to pay the $80.0 million deferred purchase price associated with the Davenport acquisition if a public offering of Summit Inc.’s Class A common stock cannot be effected by December 31, 2015. Summit Holdings paid a $1.8 million commitment fee to BCP in the six months ended June 27, 2015. Blackstone Advisory Partners L.P., an affiliate of Blackstone, served as an initial purchaser of $5.75 million and $13.0 million principal amount of the 2020 Notes issued in September 2014 and January 2014, respectively, and received compensation in connection therewith. Cement sales to companies owned by a former noncontrolling member of Continental Cement were approximately $1.4 million during the period between December 28, 2014 and March 11, 2015 and $4.5 million and $6.2 million during the three and six months ended June 28, 2014, respectively. Accounts receivables due from the former noncontrolling member were $0.2 million as of December 27, 2014. In the first quarter of 2014, the Company made an interest payment of $0.7 million to a certain former noncontrolling member of Continental Cement for a related party note. The principal balance on the note was repaid in 2012. In the six months ended June 28, 2014, the Company sold certain assets associated with the production of concrete blocks, including inventory and equipment, to a related party for $2.3 million.
Summit Materials, LLC [Member]
Related Party Transactions	12. RELATED PARTY TRANSACTIONS Under the terms of a transaction and management fee agreement between Summit Holdings and Blackstone Management Partners L.L.C. (“BMP”), whose affiliates include controlling stockholders of the Summit Inc., BMP provided monitoring, advisory and consulting services to the Company through March 17, 2015. Under the terms of the agreement, BMP was permitted to assign, and had assigned, a portion of the fees to which it is entitled to Silverhawk Summit, L.P. and to certain other equity investors. The management fee was calculated based on the greater of $300,000 or 2.0% of the Company’s annual consolidated profit, as defined in the agreement, which are included in general and administrative expenses. The Company incurred management fees due to BMP totaling $1.0 million during the period between December 28, 2014 and March 17, 2015 and $1.3 million and $2.3 million in the three and six months ended June 28, 2014, respectively. During these periods, the Company paid immaterial amounts to Silverhawk Summit, L.P. and to other equity investors. Also under the terms of the transaction and management fee agreement, BMP undertook financial and structural analysis, due diligence investigations, corporate strategy and other advisory services and negotiation assistance related to acquisitions for which the Company paid BMP transaction fees equal to 1.0% of the aggregate enterprise value of any acquired entity or, if such transaction was structured as an asset purchase or sale, 1.0% of the consideration paid for or received in respect of the assets acquired or disposed. The Company paid BMP $0.6 million and $2.3 million during the three and six months ended June 28, 2014, respectively. During these periods, the Company paid immaterial amounts to Silverhawk Summit, L.P. and to other equity investors. The acquisition-related fees paid pursuant to this agreement are included in transaction costs. In connection with the IPO, the transaction and management fee agreement with BMP was terminated on March 17, 2015 for a final payment of approximately $13.8 million, $13.4 million was paid to affiliates of Blackstone and the remaining $0.4 million was paid to affiliates of Silverhawk Summit, L.P. and to certain other equity investors. In addition to the transaction and management fees paid to BMP, the Company reimburses BMP for direct expenses incurred, which were not material in the three and six months ended June 27, 2015 and June 28, 2014. On April 16, 2015, the Company entered into an agreement with Lafarge North America Inc. (“Lafarge”) to purchase certain assets, including a cement plant, a quarry and seven cement distribution terminals (the “Davenport Assets”) for a purchase price of $450.0 million cash and a cement distribution terminal in Bettendorf, Iowa. At closing, $370.0 million of the purchase price was due and the remaining $80.0 million is due to the seller no later than December 31, 2015. Summit Holdings entered into a commitment letter dated April 16, 2015, with Blackstone Capital Partners V L.P. (“BCP”) for equity financing up to $90.0 million in the form of a preferred equity interest (the “Equity Commitment Financing”). The proceeds of the Equity Commitment Financing would be used to pay the $80.0 million deferred purchase price associated with the Davenport acquisition if a public offering of Summit Inc.’s Class A common stock cannot be effected by December 31, 2015. Summit Holdings paid a $1.8 million commitment fee to BCP in the six months ended June 27, 2015. Blackstone Advisory Partners L.P., an affiliate of Blackstone, served as an initial purchaser of $5.75 million and $13.0 million principal amount of the 2020 Notes issued in September 2014 and January 2014, respectively, and received compensation in connection therewith. Cement sales to companies owned by a former noncontrolling member of Continental Cement were approximately $1.4 million during the period between December 28, 2014 and March 11, 2015 and $4.5 million and $6.2 million during the three and six months ended June 28, 2014, respectively. Accounts receivables due from the former noncontrolling member were $0.2 million as of December 27, 2014. In the first quarter of 2014, the Company made an interest payment of $0.7 million to a certain former noncontrolling member of Continental Cement for a related party note. The principal balance on the note was repaid in 2012. In the six months ended June 28, 2014, the Company sold certain assets associated with the production of concrete blocks, including inventory and equipment, to a related party for $2.3 million.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 27, 2015
Subsequent Events	13. SUBSEQUENT EVENTS On August 5, 2015, Summit Inc. priced the offering of 19,500,000 shares of its Class A common stock at a price to the public of $25.75 per share. The underwriters have been granted a 30-day option to purchase up to an additional 2,925,000 shares of Class A common stock. The offering is expected to close on August 11, 2015, subject to customary closing conditions. Summit Inc. intends to use all of the net proceeds from the offering to purchase for cash 3,750,000 newly-issued LP Units from Summit Holdings and 15,750,000 outstanding LP Units from certain pre-IPO owners, including affiliates of the Sponsors and certain of the Company’s directors and officers. Summit Holdings intends to use the proceeds it receives to pay all or a portion of the $80.0 million deferred purchase price of the Davenport Assets and for general corporate purposes. On July 17, 2015, the Company acquired certain assets of Lafarge, including a cement plant, a quarry and seven cement distribution terminals for a purchase price of $450.0 million cash and a cement distribution terminal in Bettendorf, Iowa. Due to the recent nature of the acquisition, it is impracticable to include a schedule of the fair value of the assets acquired and liabilities assumed as of the acquisition date and the Davenport Assets’ interim results of operations for the three and six months ended June 30, 2015. On July 8, 2015, the Issuers issued $350.0 million in aggregate principal amount of 6.125% senior notes due July 15, 2023 (the “2023 Notes”). The 2023 Notes were issued at 100% of their par value. Interest on the 2023 Notes is payable semi-annually on January 15 and July 15 of each year commencing on January 15, 2016. On July 17, 2015, Summit LLC refinanced its term loan under the Senior Secured Credit Facilities (the “Refinancing”). The Refinancing, among other things: (i) reduced the applicable margins used to calculate interest rates for term loans under our Senior Secured Credit Facilities to 3.25% for LIBOR rate loans and 2.25% for base rate loans, subject to a LIBOR floor of 1.00% (and one 25 basis point step down upon Summit LLC achieving a certain first lien net leverage ratio); (ii) increased term loans borrowed under our term loan facility to an aggregate $650.0 million; and (iii) created additional flexibility under the financial maintenance covenants, which are tested quarterly, by increasing the applicable maximum Consolidated First Lien Net Leverage Ratio (as defined in the credit agreement governing the Senior Secured Credit Facilities). The Company used the net proceeds from the 2023 Notes and the Refinancing to finance an initial $370.0 million cash purchase price for the Davenport Assets, to refinance its existing senior secured term loan facility, to redeem $183.0 million aggregate principal amount of its outstanding 2020 Notes and to pay related fees and expenses. The remaining $80.0 million of the purchase price for the Davenport Assets is due to Lafarge no later than December 31, 2015 and accrues interest at an annual rate of 7.5%, payable monthly.
Summit Materials, LLC [Member]
Subsequent Events	14. SUBSEQUENT EVENTS On August 5, 2015, Summit Inc. priced the offering of 19,500,000 shares of its Class A common stock at a price to the public of $25.75 per share. The underwriters have been granted a 30-day option to purchase up to an additional 2,925,000 shares of Class A common stock. The offering is expected to close on August 11, 2015, subject to customary closing conditions. Summit Inc. intends to use all of the net proceeds from the offering to purchase for cash 3,750,000 newly-issued LP Units from Summit Holdings and 15,750,000 outstanding LP Units from certain pre-IPO owners, including affiliates of the Sponsors and certain of the Company’s directors and officers. Summit Holdings intends to use the proceeds it receives to pay all or a portion of the $80.0 million deferred purchase price of the Davenport Assets and for general purposes. On July 17, 2015, the Company acquired certain assets of Lafarge, including a cement plant, a quarry and seven cement distribution terminals for a purchase price of $450.0 million cash and a cement distribution terminal in Bettendorf, Iowa. Due to the recent nature of the acquisition, it is impracticable to include a schedule of the fair value of the assets acquired and liabilities assumed as of the acquisition date and the Davenport Assets’ interim results of operations for the three and six months ended June 30, 2015. On July 8, 2015, the Issuers issued $350.0 million in aggregate principal amount of 6.125% senior notes due July 15, 2023 (the “2023 Notes”). The 2023 Notes were issued at 100% of their par value. Interest on the 2023 Notes is payable semi-annually on January 15 and July 15 of each year commencing on January 15, 2016. On July 17, 2015, the Company refinanced its term loan under the Senior Secured Credit Facilities (the “Refinancing”). The Refinancing, among other things: (i) reduced the applicable margins used to calculate interest rates for term loans under our Senior Secured Credit Facilities to 3.25% for LIBOR rate loans and 2.25% for base rate loans, subject to a LIBOR floor of 1.00% (and one 25 basis point step down upon Summit LLC achieving a certain first lien net leverage ratio); (ii) increased term loans borrowed under our term loan facility to an aggregate $650.0 million; and (iii) created additional flexibility under the financial maintenance covenants, which are tested quarterly, by increasing the applicable maximum Consolidated First Lien Net Leverage Ratio (as defined in the Credit Agreement). The Company used the net proceeds from the 2023 Notes and the Refinancing to finance an initial $370.0 million cash purchase price for the Davenport Assets, to refinance its existing senior secured term loan facility, to redeem $183.0 million aggregate principal amount of its outstanding 2020 Notes and to pay related fees and expenses. The remaining $80.0 million of the purchase price for the Davenport Assets is due to Lafarge no later than December 31, 2015 and accrues interest at an annual rate of 7.5%, payable monthly.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	6 Months Ended
	Jun. 27, 2015
Summit Materials, LLC [Member]
Accumulated Other Comprehensive Loss	7. ACCUMULATED OTHER COMPREHENSIVE LOSS The changes in each component of accumulated other comprehensive loss consisted of the following: Change in Foreign currency Accumulated Balance — December 27, 2014 $ (9,730 ) $ (5,816 ) $ (15,546 ) Foreign currency translation adjustment — (5,235 ) (5,235 ) Balance — June 27, 2015 $ (9,730 ) $ (11,051 ) $ (20,781 ) Balance — December 28, 2013 $ (6,045 ) $ — $ (6,045 ) Postretirement curtailment adjustment (942 ) — (942 ) Postretirement liability adjustment 1,515 — 1,515 Balance —June 28, 2014 $ (5,472 ) $ — $ (5,472 )

2020 Notes' Guarantor and Non-G

2020 Notes' Guarantor and Non-Guarantor Financial Information	6 Months Ended
	Jun. 27, 2015
Summit Materials, LLC [Member]
2020 Notes' Guarantor and Non-Guarantor Financial Information	13. 2020 NOTES’ GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION Summit LLC’s domestic wholly-owned subsidiary companies other than Finance Corp. (the “Guarantors”) are named as guarantors (collectively, the “Guarantors”) of the 2020 Notes. Certain other partially-owned subsidiaries and a non-U.S. entity do not guarantee the 2020 Notes (collectively, the “Non-Guarantors”). The Guarantors provide a joint and several, full and unconditional guarantee of the 2020 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. On March 17, 2015, the noncontrolling interests of Continental Cement were purchased resulting in Continental Cement being a wholly-owned indirect subsidiary of Summit LLC. Continental Cement’s results of operations and cash flows are reflected with the Guarantors for the three and six months ended June 27, 2015. In 2014, Continental Cement’s results are shown separately as a Non Wholly-owned Guarantor. 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 June 27, 2015 Issuers Wholly- Non- Eliminations Consolidated Assets Current assets: Cash $ 10,225 $ 808 $ 9,656 $ (8,119 ) $ 12,570 Accounts receivable, net — 153,726 11,214 (881 ) 164,059 Intercompany receivables 429,542 7,114 6,183 (442,839 ) — Cost and estimated earnings in excess of billings — 24,490 231 — 24,721 Inventories — 121,882 6,535 — 128,417 Other current assets 1,206 17,051 1,596 — 19,853 Total current assets 440,973 325,071 35,415 (451,839 ) 349,620 Property, plant and equipment, net 8,117 948,314 28,650 — 985,081 Goodwill — 366,669 51,990 — 418,659 Intangible assets, net — 14,292 1,965 — 16,257 Other assets 1,248,995 138,530 1,352 (1,343,002 ) 45,875 Total assets $ 1,698,085 $ 1,792,876 $ 119,372 $ (1,794,841 ) $ 1,815,492 Liabilities, Redeemable Noncontrolling Interest and Member’s Interest Current liabilities: Current portion of debt $ 71,275 $ 4,465 $ — $ (4,465 ) $ 71,275 Current portion of acquisition-related liabilities — 19,895 — — 19,895 Accounts payable 4,266 81,677 5,760 (881 ) 90,822 Accrued expenses 29,416 67,035 2,446 (8,119 ) 90,778 Intercompany payables 46,451 397,217 3,756 (442,839 ) 4,585 Billings in excess of costs and estimated earnings — 8,319 22 — 8,341 Total current liabilities 151,408 578,608 11,984 (456,304 ) 285,696 Long-term debt 755,972 517,598 — (517,598 ) 755,972 Acquisition-related liabilities — 34,502 — — 34,502 Other noncurrent liabilities 706 110,974 57,580 (55,107 ) 114,153 Total liabilities 908,086 1,241,682 69,564 (1,029,009 ) 1,190,323 Redeemable noncontrolling interest — — — — — Redeemable members’ interest — — — — — Total stockholders’ equity/partners’ interest 789,999 551,194 49,808 (765,832 ) 625,169 Total liabilities, redeemable noncontrolling interest and member’s interest $ 1,698,085 $ 1,792,876 $ 119,372 $ (1,794,841 ) $ 1,815,492 Condensed Consolidating Balance Sheets December 27, 2014 Issuers Non- Wholly- owned Wholly- owned Non- Eliminations Consolidated Assets Current assets: Cash $ 10,837 $ 2 $ 695 $ 8,793 $ (7,112 ) $ 13,215 Accounts receivable, net 1 6,629 124,380 11,525 (1,233 ) 141,302 Intercompany receivables 376,344 4,095 30,539 4,052 (415,030 ) — Cost and estimated earnings in excess of billings — — 9,819 355 — 10,174 Inventories — 8,696 98,188 4,669 — 111,553 Other current assets 7,148 464 9,638 1,775 (1,853 ) 17,172 Total current assets 394,330 19,886 273,259 31,169 (425,228 ) 293,416 Property, plant and equipment, net 7,035 302,524 610,717 30,325 — 950,601 Goodwill — 23,124 340,969 55,177 — 419,270 Intangible assets, net — 542 14,245 2,860 — 17,647 Other assets 1,153,204 25,233 125,462 1,362 (1,256,418 ) 48,843 Total assets $ 1,554,569 $ 371,309 $ 1,364,652 $ 120,893 $ (1,681,646 ) $ 1,729,777 Liabilities, Redeemable Noncontrolling Interest and Member’s Interest Current liabilities: Current portion of debt $ 5,275 $ 1,273 $ 3,990 $ — $ (5,263 ) $ 5,275 Current portion of acquisition-related liabilities 166 — 18,236 — — 18,402 Accounts payable 3,655 6,845 65,018 4,569 (1,233 ) 78,854 Accrued expenses 37,101 10,178 59,477 3,705 (8,965 ) 101,496 Intercompany payables 162,728 4,052 245,416 2,834 (415,030 ) — Billings in excess of costs and estimated earnings — — 8,931 27 — 8,958 Total current liabilities 208,925 22,348 401,068 11,135 (430,491 ) 212,985 Long-term debt 1,059,642 153,318 480,599 — (633,917 ) 1,059,642 Acquisition-related liabilities — — 42,736 — — 42,736 Other noncurrent liabilities 796 24,787 65,479 57,736 (55,107 ) 93,691 Total liabilities 1,269,363 200,453 989,882 68,871 (1,119,515 ) 1,409,054 Redeemable noncontrolling interest — — — — 33,740 33,740 Redeemable members’ interest — 34,543 — — (34,543 ) — Total stockholders’ equity/partners’ interest 285,206 136,313 374,770 52,022 (561,328 ) 286,983 Total liabilities, redeemable noncontrolling interest and member’s interest $ 1,554,569 $ 371,309 $ 1,364,652 $ 120,893 $ (1,681,646 ) $ 1,729,777 Condensed Consolidating Statements of Operations For the three months ended June 27, 2015 Issuers Wholly- Non- Eliminations Consolidated Revenue $ — $ 346,309 $ 23,702 $ (5,068 ) $ 364,943 Cost of revenue (excluding items shown separately below) — 240,637 13,601 (5,068 ) 249,170 General and administrative expenses 14,972 29,446 1,669 — 46,087 Depreciation, depletion, amortization and accretion 567 25,471 1,348 — 27,386 Operating (loss) income (15,539 ) 50,755 7,084 — 42,300 Other (income) expense, net (22,202 ) 2,761 10 50,406 30,975 Interest expense 6,352 13,990 909 (4,147 ) 17,104 Income from continuing operations before taxes 311 34,004 6,165 (46,259 ) (5,779 ) Income tax benefit (expense) — (5,625 ) 280 — (5,345 ) Income from continuing operations 311 39,629 5,885 (46,259 ) (434 ) Income from discontinued operations — (758 ) — — (758 ) Net income 311 40,387 5,885 (46,259 ) 324 Net income attributable to minority interest — — — 13 13 Net income attributable to member of Summit Materials, LLC $ 311 $ 40,387 $ 5,885 $ (46,272 ) $ 311 Comprehensive income attributable to member of Summit Materials, LLC $ 1,375 $ 40,387 $ 6,949 $ (47,336 ) $ 1,375 Condensed Consolidating Statements of Operations For the three months ended June 28, 2014 Issuers Non- Wholly- owned Wholly- Non- Eliminations Consolidated Revenue $ — $ 27,557 $ 287,307 $ 14,942 $ (5,511 ) $ 324,295 Cost of revenue (excluding items shown separately below) — 16,724 210,693 9,856 (5,511 ) 231,762 General and administrative expenses 10,002 1,900 25,080 290 — 37,272 Depreciation, depletion, amortization and accretion 338 3,703 17,020 278 — 21,339 Operating (loss) income (10,340 ) 5,230 34,514 4,518 — 33,922 Other (income) expense, net (29,100 ) (1,261 ) (1,360 ) (3 ) 31,027 (697 ) Interest expense 7,932 3,011 12,643 31 (1,966 ) 21,651 Income from continuing operations before taxes 10,828 3,480 23,231 4,490 (29,061 ) 12,968 Income tax benefit (expense) (1,427 ) — 563 — — (864 ) Income from continuing operations 12,255 3,480 22,668 4,490 (29,061 ) 13,832 Income from discontinued operations — — (369 ) — — (369 ) Net income 12,255 3,480 23,037 4,490 (29,061 ) 14,201 Net income attributable to minority interest — — — — 1,946 1,946 Net income attributable to member of Summit Materials, LLC $ 12,255 $ 3,480 $ 23,037 $ 4,490 $ (31,007 ) $ 12,255 Comprehensive income attributable to member of Summit Materials, LLC $ 12,255 $ 3,480 $ 23,037 $ 4,490 $ (31,007 ) $ 12,255 Condensed Consolidating Statements of Operations For the six months ended June 27, 2015 Issuers Wholly- Non- Eliminations Consolidated Revenue $ — $ 525,652 $ 57,349 $ (24,071 ) $ 558,930 Cost of revenue (excluding items shown separately below) — 391,864 39,646 (24,071 ) 407,439 General and administrative expenses 52,753 58,596 3,336 — 114,685 Depreciation, depletion, amortization and accretion 1,058 49,623 2,831 — 53,512 Operating (loss) income (53,811 ) 25,569 11,536 — (16,706 ) Other (income) expense, net 3,583 3,500 159 24,923 32,165 Interest expense 20,150 30,045 1,790 (10,772 ) 41,213 Income from continuing operations before taxes (77,544 ) (7,976 ) 9,587 (14,151 ) (90,084 ) Income tax benefit (expense) — (10,163 ) 350 — (9,813 ) Income from continuing operations (77,544 ) 2,187 9,237 (14,151 ) (80,271 ) Income from discontinued operations — (758 ) — — (758 ) Net income (77,544 ) 2,945 9,237 (14,151 ) (79,513 ) Net income attributable to minority interest — — — (1,969 ) (1,969 ) Net income attributable to member of Summit Materials, LLC $ (77,544 ) $ 2,945 $ 9,237 $ (12,182 ) $ (77,544 ) Comprehensive income attributable to member of Summit Materials, LLC $ (82,779 ) $ 2,945 $ 4,002 $ (6,947 ) $ (82,779 ) Condensed Consolidating Statements of Operations For the six months ended June 28, 2014 Issuers Non- Wholly- owned Wholly- Non- Eliminations Consolidated Revenue $ — $ 35,264 $ 427,717 $ 21,274 $ (8,869 ) $ 475,386 Cost of revenue (excluding items shown separately below) — 27,626 328,318 13,362 (8,869 ) 360,437 General and administrative expenses 17,690 3,574 53,521 566 — 75,351 Depreciation, depletion, amortization and accretion 642 6,777 32,731 545 — 40,695 Operating (loss) income (18,332 ) (2,713 ) 13,147 6,801 — (1,097 ) Other expense (income), net 7,725 (1,358 ) (1,553 ) 45 (5,750 ) (891 ) Interest expense 13,668 5,857 24,415 56 (3,526 ) 40,470 (Loss) income from continuing operations before taxes (39,725 ) (7,212 ) (9,715 ) 6,700 9,276 (40,676 ) Income tax benefit (1,427 ) — (33 ) — — (1,460 ) (Loss) income from continuing operations (38,298 ) (7,212 ) (9,682 ) 6,700 9,276 (39,216 ) Income from discontinued operations — — (349 ) — — (349 ) Net (loss) income (38,298 ) (7,212 ) (9,333 ) 6,700 9,276 (38,867 ) Net loss attributable to noncontrolling interest — — — — (569 ) (569 ) Net (loss) income attributable to member of Summit Materials, LLC $ (38,298 ) $ (7,212 ) $ (9,333 ) $ 6,700 $ 9,845 $ (38,298 ) Comprehensive (loss) income attributable to member of Summit Materials, LLC $ (38,298 ) $ (6,394 ) $ (9,333 ) $ 6,700 $ 9,600 $ (37,725 ) Condensed Consolidating Statements of Cash Flows For the six months ended June 27, 2015 Issuers Wholly- Non- Eliminations Consolidated Net cash (used in) provided by operating activities $ (93,127 ) $ 6,775 $ 6,435 $ (167 ) $ (80,084 ) Cash flow from investing activities: Acquisitions, net of cash acquired — (15,863 ) — — (15,863 ) Purchase of property, plant and equipment (1,904 ) (40,969 ) (506 ) — (43,379 ) Proceeds from the sale of property, plant, and equipment — 5,989 50 — 6,039 Other — 610 — — 610 Net cash used for investing activities (1,904 ) (50,233 ) (456 ) — (52,593 ) Cash flow from financing activities: Proceeds from investment by member 397,975 — — — 397,975 Capital issuance costs (9,373 ) (9,373 ) Net proceeds from debt issuance 242,000 — — — 242,000 Loans received from and payments made on loans from other Summit Companies (169,065 ) 176,243 (5,116 ) (2,062 ) — Payments on long-term debt (349,980 ) (120,703 ) — 1,055 (469,628 ) Payments on acquisition-related liabilities (166 ) (11,804 ) — — (11,970 ) Financing costs (5,130 ) — — — (5,130 ) Distributions from partnership (11,842 ) — — — (11,842 ) Other — (167 ) 167 — Net cash provided by (used for) financing activities 94,419 43,569 (5,116 ) (840 ) 132,032 Net increase (decrease) in cash (612 ) 111 863 (1,007 ) (645 ) Cash — Beginning of period 10,837 697 8,793 (7,112 ) 13,215 Cash— End of period $ 10,225 $ 808 $ 9,656 $ (8,119 ) $ 12,570 Condensed Consolidating Statements of Cash Flows For the six months ended June 28, 2014 Issuers Non- Wholly- Wholly- Non- Eliminations Consolidated Net cash used in operating activities $ (18,665 ) $ (13,153 ) $ (13,412 ) $ 168 $ (818 ) $ (45,880 ) Cash flow from investing activities: Acquisitions, net of cash acquired (181,754 ) — (53,116 ) — — (234,870 ) Purchase of property, plant and equipment (2,428 ) (11,829 ) (34,666 ) (337 ) — (49,260 ) Proceeds from the sale of property, plant, and equipment — — 5,912 73 — 5,985 Other — — (409 ) — 1,166 757 Net cash (used for) provided by investing activities (184,182 ) (11,829 ) (82,279 ) (264 ) 1,166 (277,388 ) Cash flow from financing activities: Proceeds from investment by member 24,350 — 1,166 (1,166 ) 24,350 Net proceeds from debt issuance 424,750 — — — — 424,750 Loans received from and payments made on loans from other Summit Companies (123,441 ) 25,234 104,121 22 (5,936 ) — Payments on long-term debt (104,060 ) (254 ) (4,932 ) — — (109,246 ) Payments on acquisition-related liabilities (1,000 ) — (3,259 ) — — (4,259 ) Financing costs (6,354 ) — — — — (6,354 ) Other (88 ) — (1,000 ) — 1,000 (88 ) Net cash provided by (used for) financing activities 214,157 24,980 94,930 1,188 (6,102 ) 329,153 Net increase (decrease) in cash 11,310 (2 ) (761 ) 1,092 (5,754 ) 5,885 Cash — Beginning of period 10,375 9 3,442 3,631 (2,540 ) 14,917 Cash— End of period $ 21,685 $ 7 $ 2,681 $ 4,723 $ (8,294 ) $ 20,802

Summary of Organization and S23

Summary of Organization and Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 27, 2015
Initial Public Offering	Initial Public Offering 1 2
Basis of Presentation	Basis of Presentation Management believes that these consolidated interim financial statements include all adjustments, normal and recurring in nature, that are necessary to present fairly the financial position of the Company as of June 27, 2015, the results of operations for the three and six months ended June 27, 2015 and June 28, 2014 and cash flows for the six months ended June 27, 2015 and June 28, 2014. All significant intercompany balances and transactions have been eliminated. 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 occurs approximately once every seven years and will occur in 2015. The additional week in the 53-week year will be included in the fourth quarter. The consolidated financial statements of the Company include the accounts of Summit Inc. and its subsidiaries, including noncontrolling interests. As a result of the Reorganization, Summit Holdings became a variable interest entity. Summit Inc. is the primary beneficiary of Summit Holdings as a result of its 100% voting power and control over Summit Holdings and its obligation to absorb losses and its right to receive benefits of Summit Holdings and thus consolidates Summit Holdings in its consolidated financial statements with a corresponding noncontrolling interest elimination of 72.2%. Noncontrolling interests in consolidated subsidiaries represent a 20% ownership in Ohio Valley Asphalt, LLC and, prior to the IPO and concurrent purchase of the noncontrolling interests of Continental Cement, a 30% redeemable ownership in Continental Cement.
Use of Estimates	Use of Estimates
Business and Credit Concentrations	Business and Credit Concentrations—
Earnings per Share	Earnings per Share—
Fair Value Measurements	Fair Value Measurements— June 27, December 27, 2015 2014 Current portion of acquisition-related liabilities: Current portion of contingent consideration $ 4,486 $ 2,375 Acquisition-related liabilities: Contingent consideration $ 4,193 $ 5,379 The fair values are based on unobservable, or Level 3, inputs, including projected probability-weighted cash payments and an 11.0% 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. There were no material valuation adjustments to contingent consideration obligations in the three or six months ended June 27, 2015 or June 28, 2014.
Financial Instruments	Financial Instruments June 27, 2015 December 27, 2014 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt (1) $ 780,155 $ 827,247 $ 1,101,873 $ 1,064,917 Level 3 Current portion of deferred consideration and noncompete obligations (2) 17,909 17,909 16,027 16,027 Long term portion of deferred consideration and noncompete obligations (3) 38,676 38,676 37,357 37,357 (1) $5.3 million included in current portion of debt as of June 27, 2015 and December 27, 2014. Excludes $66.0 million outstanding on the revolving credit facility as of June 27, 2015. (2) Included in current portion of acquisition-related liabilities on the balance sheet. (3) Included in acquisition-related liabilities on the balance sheet. 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.
Redeemable Noncontrolling Interest	Redeemable Noncontrolling Interest
New Accounting Standards	New Accounting Standards — Simplifying the Presentation of Debt Issuance Costs In April 2015, the FASB issued a new accounting standard, ASU 2015-04, Practical Expedient for the Measurement Date of an Employer’s Defined Benefit Obligation and Plan Assets In May 2014, the FASB issued a new accounting standard to improve and converge the financial reporting requirements for revenue from contracts with customers. ASU No. 2014-09, Revenue from Contracts with Customers
Reclassifications	Reclassifications
Summit Materials, LLC [Member]
Basis of Presentation	Basis of Presentation 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 occurs approximately once every seven years and will occur in 2015. The additional week in the 53-week year will be included in the fourth quarter. The consolidated financial statements of the Company include the accounts of Summit LLC and its subsidiaries, including noncontrolling interests. All significant intercompany balances and transactions have been eliminated. Noncontrolling interests in consolidated subsidiaries represent a 20% ownership in Ohio Valley Asphalt, LLC and, prior to the IPO and concurrent purchase of the noncontrolling interests of Continental Cement Company, L.L.C. (“Continental Cement”), a 30% redeemable ownership in Continental Cement.
Use of Estimates	Use of Estimates
Business and Credit Concentrations	Business and Credit Concentrations—
Fair Value Measurements	Fair Value Measurements— June 27, December 27, 2015 2014 Current portion of acquisition-related liabilities: Current portion of contingent consideration $ 4,486 $ 2,375 Acquisition- related liabilities: Contingent consideration $ 4,193 $ 5,379 The fair values are based on unobservable, or Level 3, inputs, including projected probability-weighted cash payments and an 11.0% 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. There were no material valuation adjustments to contingent consideration obligations in the three or six months ended June 27, 2015 or June 28, 2014.
Financial Instruments	Financial Instruments June 27, 2015 December 27, 2014 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt (1) $ 780,155 $ 827,247 $ 1,101,873 $ 1,064,917 Level 3 Current portion of deferred consideration and noncompete obligations (2) 15,409 15,409 16,027 16,027 Long term portion of deferred consideration and noncompete obligations (3) 30,309 30,309 37,357 37,357 (1) $5.3 million included in current portion of debt as of June 27, 2015 and December 27, 2014. Excludes $66.0 million outstanding on the revolving credit facility as of June 27, 2015. (2) Included in current portion of acquisition-related liabilities on the balance sheet. (3) Included in acquisition-related liabilities on the balance sheet. 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.
Redeemable Noncontrolling Interest	Redeemable Noncontrolling Interest
New Accounting Standards	New Accounting Standards — Simplifying the Presentation of Debt Issuance Costs In April 2015, the FASB issued a new accounting standard, ASU 2015-04, Practical Expedient for the Measurement Date of an Employer’s Defined Benefit Obligation and Plan Assets, In May 2014, the FASB issued a new accounting standard to improve and converge the financial reporting requirements for revenue from contracts with customers. ASU No. 2014-09, Revenue from Contracts with Customers
Reclassifications	Reclassifications

Summary of Organization and S24

Summary of Organization and Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 27, 2015
Schedule of Contingent Consideration Obligations Measured at Fair Value	Contingent consideration as of June 27, 2015 and December 27, 2014 was: June 27, December 27, 2015 2014 Current portion of acquisition-related liabilities: Current portion of contingent consideration $ 4,486 $ 2,375 Acquisition-related liabilities: Contingent consideration $ 4,193 $ 5,379
Schedule of Carrying Value and Fair Value of Financial Instruments	The carrying value and fair value of these financial instruments as of June 27, 2015 and December 27, 2014 was: June 27, 2015 December 27, 2014 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt (1) $ 780,155 $ 827,247 $ 1,101,873 $ 1,064,917 Level 3 Current portion of deferred consideration and noncompete obligations (2) 17,909 17,909 16,027 16,027 Long term portion of deferred consideration and noncompete obligations (3) 38,676 38,676 37,357 37,357 (1) $5.3 million included in current portion of debt as of June 27, 2015 and December 27, 2014. Excludes $66.0 million outstanding on the revolving credit facility as of June 27, 2015. (2) Included in current portion of acquisition-related liabilities on the balance sheet. (3) Included in acquisition-related liabilities on the balance sheet.
Summit Materials, LLC [Member]
Schedule of Contingent Consideration Obligations Measured at Fair Value	Contingent consideration as of June 27, 2015 and December 27, 2014 was: June 27, December 27, 2015 2014 Current portion of acquisition-related liabilities: Current portion of contingent consideration $ 4,486 $ 2,375 Acquisition- related liabilities: Contingent consideration $ 4,193 $ 5,379
Schedule of Carrying Value and Fair Value of Financial Instruments	The carrying value and fair value of these financial instruments as of June 27, 2015 and December 27, 2014 was: June 27, 2015 December 27, 2014 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt (1) $ 780,155 $ 827,247 $ 1,101,873 $ 1,064,917 Level 3 Current portion of deferred consideration and noncompete obligations (2) 15,409 15,409 16,027 16,027 Long term portion of deferred consideration and noncompete obligations (3) 30,309 30,309 37,357 37,357 (1) $5.3 million included in current portion of debt as of June 27, 2015 and December 27, 2014. Excludes $66.0 million outstanding on the revolving credit facility as of June 27, 2015. (2) Included in current portion of acquisition-related liabilities on the balance sheet. (3) Included in acquisition-related liabilities on the balance sheet.

Accounts Receivable, Net (Table

Accounts Receivable, Net (Tables)	6 Months Ended
	Jun. 27, 2015
Summary of Accounts Receivable, Net	Accounts receivable, net consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Trade accounts receivable $ 154,678 $ 131,060 Retention receivables 11,119 12,053 Receivables from related parties 629 333 Accounts receivable 166,426 143,446 Less: Allowance for doubtful accounts (2,367 ) (2,144 ) Accounts receivable, net $ 164,059 $ 141,302
Summit Materials, LLC [Member]
Summary of Accounts Receivable, Net	Accounts receivable, net consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Trade accounts receivable $ 154,678 $ 131,060 Retention receivables 11,119 12,053 Receivables from related parties 629 333 Accounts receivable 166,426 143,446 Less: Allowance for doubtful accounts (2,367 ) (2,144 ) Accounts receivable, net $ 164,059 $ 141,302

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Jun. 27, 2015
Components of Inventories	Inventories consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Aggregate stockpiles $ 91,036 $ 88,211 Finished goods 16,791 8,826 Work in process 1,882 1,801 Raw materials 18,708 12,715 Total $ 128,417 $ 111,553
Summit Materials, LLC [Member]
Components of Inventories	Inventories consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Aggregate stockpiles $ 91,036 $ 88,211 Finished goods 16,791 8,826 Work in process 1,882 1,801 Raw materials 18,708 12,715 Total $ 128,417 $ 111,553

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 27, 2015
Components of Accrued Expenses	Accrued expenses consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Interest $ 19,908 $ 32,475 Payroll and benefits 17,733 20,326 Capital lease obligations 18,400 17,530 Insurance 11,780 11,402 Non-income taxes 6,464 5,520 Professional fees 5,142 3,299 Other (1) 11,351 10,944 Total $ 90,778 $ 101,496 (1) Consists primarily of subcontractor and working capital settlement accruals.
Summit Materials, LLC [Member]
Components of Accrued Expenses	Accrued expenses consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Interest $ 19,908 $ 32,475 Payroll and benefits 17,733 20,326 Capital lease obligations 18,400 17,530 Insurance 11,780 11,402 Non-income taxes 6,464 5,520 Professional fees 5,142 3,299 Other (1) 11,351 10,944 Total $ 90,778 $ 101,496 (1) Consists primarily of subcontractor and working capital settlement accruals.

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 27, 2015
Schedule of Debt	Debt consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Revolving credit facility $ 66,000 $ — Long-term debt: $336.8 million senior notes, including a $12.9 million net premium at June 27, 2015 and $625.0 million senior notes, including a $26.5 million net premium at December 27, 2014 349,701 651,548 $413.6 million term loan, net of $2.1 million discount at June 27, 2015 and $415.7 million term loan, net of $2.3 million discount at December 27, 2014 411,546 413,369 Total 761,247 1,064,917 Current portion of long-term debt 5,275 5,275 Long-term debt $ 755,972 $ 1,059,642
Schedule of Contractual Payments of Long-Term Debt	The contractual payments of long-term debt, including current maturities, for the five years subsequent to June 27, 2015, are as follows: 2015 (six months) $ 3,165 2016 4,220 2017 4,220 2018 3,165 2019 398,790 2020 336,800 Total 750,360 Plus: Original issue net premium 10,887 Total debt $ 761,247
Summary of Activity for Deferred Financing Fees	The following table presents the activity for the deferred financing fees for the six months ended June 27, 2015 and June 28, 2014: Deferred financing fees Balance — December 27, 2014 $ 17,215 Loan origination fees 5,130 Amortization (1,701 ) Write off of deferred financing fees (5,109 ) Balance — June 27, 2015 $ 15,535 Balance — December 28, 2013 $ 11,485 Loan origination fees 6,309 Amortization (1,544 ) Balance —June 28, 2014 $ 16,250
Summit Materials, LLC [Member]
Schedule of Debt	Debt consisted of the following as of June 27, 2015 and December 27, 2014: June 27, December 27, 2015 2014 Revolving credit facility $ 66,000 $ — Long-term debt: $336.8 million senior notes, including a $12.9 million net premium at June 27, 2015 and $625.0 million senior notes, including a $26.5 million net premium at December 27, 2014 349,701 651,548 $413.6 million term loan, net of $2.1 million discount at June 27, 2015 and $415.7 million term loan, net of $2.3 million discount at December 27, 2014 411,546 413,369 Total 761,247 1,064,917 Current portion of long-term debt 5,275 5,275 Long-term debt $ 755,972 $ 1,059,642
Schedule of Contractual Payments of Long-Term Debt	The contractual payments of long-term debt, including current maturities, for the five years subsequent to June 27, 2015, are as follows: 2015 (six months) $ 3,165 2016 4,220 2017 4,220 2018 3,165 2019 398,790 2020 336,800 Total 750,360 Plus: Original issue net premium 10,887 Total debt $ 761,247
Summary of Activity for Deferred Financing Fees	The following table presents the activity for the deferred financing fees for the six months ended June 27, 2015 and June 28, 2014: Deferred financing fees Balance — December 27, 2014 $ 17,215 Loan origination fees 5,130 Amortization (1,701 ) Write off of deferred financing fees (5,109 ) Balance — June 27, 2015 $ 15,535 Balance — December 28, 2013 $ 11,485 Loan origination fees 6,309 Amortization (1,544 ) Balance —June 28, 2014 $ 16,250

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 27, 2015
Earnings Per Share [Abstract]
Schedule of Basic to Diluted Loss Per Share	The following table reconciles basic to diluted loss per share: June 27, 2015 Three months Six months (in thousands, except per share amounts) ended ended Net loss attributable to Summit Materials, Inc.: Net loss attributable to Summit Inc. $ (205 ) $ (10,356 ) Add: Noncontrolling interest impact of LP Unit conversion (1) — (958 ) Diluted net loss attributable to Summit Inc. $ (205 ) $ (11,314 ) Weighted-average common shares: Weighted average shares of Class A shares outstanding 26,584,738 26,584,738 Basic earnings per share $ (0.01 ) $ (0.39 ) Weighted average shares of Class A shares outstanding 26,584,738 26,584,738 Add: weighted average of LP Units — 1,826,152 Weighted average dilutive shares outstanding 26,584,738 28,410,890 Diluted earnings per share $ (0.01 ) $ (0.40 ) (1) Diluted net loss for the six months ended June 27, 2015 considers the change in ownership percentage from 27.8% to 30.4% as a result of the LP unit conversions.

Supplemental Cash Flow Inform30

Supplemental Cash Flow Information (Tables)	6 Months Ended
	Jun. 27, 2015
Schedule of Supplemental Cash Flow Information	Supplemental cash flow information is as follows: Six months ended June 27, June 28, 2015 2014 Cash payments: Interest $ 50,646 $ 25,881 Income taxes 1,257 1,320 Non cash financing activities: Purchase of noncontrolling interest in Continental Cement $ (29,102 ) $ —
Summit Materials, LLC [Member]
Schedule of Supplemental Cash Flow Information	Supplemental cash flow information is as follows: Six months ended June 27, June 28, 2015 2014 Cash payments: Interest $ 50,646 $ 25,881 Income taxes 1,257 1,320 Non cash financing activities: Purchase of noncontrolling interest in Continental Cement $ (64,102 ) $ —

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 27, 2015
Summary of Financial Data for Company's Reportable Business Segments	The following tables display selected financial data for the Company’s reportable segments: Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Revenue: West region $ 208,068 $ 172,236 $ 335,742 $ 267,130 Central region 117,920 109,117 174,529 156,659 East region 38,955 42,942 48,659 51,597 Total revenue $ 364,943 $ 324,295 $ 558,930 $ 475,386 Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Adjusted EBITDA West region $ 39,497 $ 30,750 $ 51,366 $ 32,541 Central region 35,518 28,823 36,228 28,400 East region 9,580 7,932 1,713 (1,406 ) Corporate and other (15,011 ) (11,547 ) (24,698 ) (19,046 ) Total reportable segments and corporate 69,584 55,958 64,609 40,489 Interest expense 17,395 21,651 41,504 40,470 Depreciation, depletion, amortization and accretion 27,386 21,339 53,512 40,695 Initial public offering costs — — 28,296 — Loss on debt financings 30,873 — 31,672 — (Loss) income from continuing operations before taxes $ (6,070 ) $ 12,968 $ (90,375 ) $ (40,676 ) Six months ended June 27, June 28, 2015 2014 Cash paid for capital expenditures: West region $ 18,037 $ 17,924 Central region 15,920 23,372 East region 7,518 5,533 Total reportable segments 41,475 46,829 Corporate and other 1,904 2,431 Total capital expenditures $ 43,379 $ 49,260 Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Depreciation, depletion, amortization and accretion: West region $ 12,634 $ 7,667 $ 24,722 $ 14,414 Central region 11,348 9,504 21,420 18,351 East region 2,835 3,831 6,312 7,288 Total reportable segments 26,817 21,002 52,454 40,053 Corporate and other 569 337 1,058 642 Total depreciation, depletion, amortization and accretion $ 27,386 $ 21,339 $ 53,512 $ 40,695 June 27, December 27, 2015 2014 Total assets: West region $ 824,892 $ 777,981 Central region 726,976 704,134 East region 230,353 221,598 Total reportable segments 1,782,221 1,703,713 Corporate and other 33,271 26,064 Total $ 1,815,492 $ 1,729,777 Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Revenue by product:* Aggregates $ 79,929 $ 59,816 $ 132,266 $ 91,366 Cement 30,177 27,557 41,996 35,264 Ready-mixed concrete 89,309 71,389 159,397 113,769 Asphalt 85,329 74,686 106,243 99,082 Paving and related services 137,330 144,911 181,229 200,768 Other (57,131 ) (54,064 ) (62,201 ) (64,863 ) Total revenue $ 364,943 $ 324,295 $ 558,930 $ 475,386 * Revenue by product includes intercompany and intracompany sales transferred at market value. The elimination of intracompany transactions is included in Other. Revenue from the liquid asphalt terminals is included in asphalt revenue.
Summit Materials, LLC [Member]
Summary of Financial Data for Company's Reportable Business Segments	The following tables display selected financial data for the Company’s reportable segments: Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Revenue: West region $ 208,068 $ 172,236 $ 335,742 $ 267,130 Central region 117,920 109,117 174,529 156,659 East region 38,955 42,942 48,659 51,597 Total revenue $ 364,943 $ 324,295 $ 558,930 $ 475,386 Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Adjusted EBITDA West region $ 39,497 $ 30,750 $ 51,366 $ 32,541 Central region 35,518 28,823 36,228 28,400 East region 9,580 7,932 1,713 (1,406 ) Corporate and other (15,011 ) (11,547 ) (24,698 ) (19,046 ) Total reportable segments and corporate 69,584 55,958 64,609 40,489 Interest expense 17,104 21,651 41,213 40,470 Depreciation, depletion, amortization and accretion 27,386 21,339 53,512 40,695 Initial public offering costs — — 28,296 — Loss on debt financings 30,873 — 31,672 — (Loss) income from continuing operations before taxes $ (5,779 ) $ 12,968 $ (90,084 ) $ (40,676 ) Six months ended June 27, June 28, 2015 2014 Cash paid for capital expenditures: West region $ 18,037 $ 17,924 Central region 15,920 23,372 East region 7,518 5,533 Total reportable segments 41,475 46,829 Corporate and other 1,904 2,431 Total capital expenditures $ 43,379 $ 49,260 Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Depreciation, depletion, amortization and accretion: West region $ 12,634 $ 7,667 $ 24,722 $ 14,414 Central region 11,348 9,504 21,420 18,351 East region 2,835 3,831 6,312 7,288 Total reportable segments 26,817 21,002 52,454 40,053 Corporate and other 569 337 1,058 642 Total depreciation, depletion, amortization and accretion $ 27,386 $ 21,339 $ 53,512 $ 40,695 June 27, December 27, 2015 2014 Total assets: West region $ 824,892 $ 777,981 Central region 726,976 704,134 East region 230,353 221,598 Total reportable segments 1,782,221 1,703,713 Corporate and other 33,271 26,064 Total $ 1,815,492 $ 1,729,777 Three months ended Six months ended June 27, June 28, June 27, June 28, 2015 2014 2015 2014 Revenue by product:* Aggregates $ 79,929 $ 59,816 $ 132,266 $ 91,366 Cement 30,177 27,557 41,996 35,264 Ready-mixed concrete 89,309 71,389 159,397 113,769 Asphalt 85,329 74,686 106,243 99,082 Paving and related services 137,330 144,911 181,229 200,768 Other (57,131 ) (54,064 ) (62,201 ) (64,863 ) Total revenue $ 364,943 $ 324,295 $ 558,930 $ 475,386 * Revenue by product includes intercompany and intracompany sales transferred at market value. The elimination of intracompany transactions is included in Other. Revenue from the liquid asphalt terminals is included in asphalt revenue.

Accumulated Other Comprehensi32

Accumulated Other Comprehensive Loss (Tables)	6 Months Ended
	Jun. 27, 2015
Summit Materials, LLC [Member]
Accumulated Other Comprehensive Loss	The changes in each component of accumulated other comprehensive loss consisted of the following: Change in Foreign currency Accumulated Balance — December 27, 2014 $ (9,730 ) $ (5,816 ) $ (15,546 ) Foreign currency translation adjustment — (5,235 ) (5,235 ) Balance — June 27, 2015 $ (9,730 ) $ (11,051 ) $ (20,781 ) Balance — December 28, 2013 $ (6,045 ) $ — $ (6,045 ) Postretirement curtailment adjustment (942 ) — (942 ) Postretirement liability adjustment 1,515 — 1,515 Balance —June 28, 2014 $ (5,472 ) $ — $ (5,472 )

2020 Notes' Guarantor and Non33

2020 Notes' Guarantor and Non-Guarantor Financial Information (Tables) - Summit Materials, LLC [Member]	6 Months Ended
	Jun. 27, 2015
Condensed Consolidating Balance Sheets	Condensed Consolidating Balance Sheets June 27, 2015 Issuers Wholly- Non- Eliminations Consolidated Assets Current assets: Cash $ 10,225 $ 808 $ 9,656 $ (8,119 ) $ 12,570 Accounts receivable, net — 153,726 11,214 (881 ) 164,059 Intercompany receivables 429,542 7,114 6,183 (442,839 ) — Cost and estimated earnings in excess of billings — 24,490 231 — 24,721 Inventories — 121,882 6,535 — 128,417 Other current assets 1,206 17,051 1,596 — 19,853 Total current assets 440,973 325,071 35,415 (451,839 ) 349,620 Property, plant and equipment, net 8,117 948,314 28,650 — 985,081 Goodwill — 366,669 51,990 — 418,659 Intangible assets, net — 14,292 1,965 — 16,257 Other assets 1,248,995 138,530 1,352 (1,343,002 ) 45,875 Total assets $ 1,698,085 $ 1,792,876 $ 119,372 $ (1,794,841 ) $ 1,815,492 Liabilities, Redeemable Noncontrolling Interest and Member’s Interest Current liabilities: Current portion of debt $ 71,275 $ 4,465 $ — $ (4,465 ) $ 71,275 Current portion of acquisition-related liabilities — 19,895 — — 19,895 Accounts payable 4,266 81,677 5,760 (881 ) 90,822 Accrued expenses 29,416 67,035 2,446 (8,119 ) 90,778 Intercompany payables 46,451 397,217 3,756 (442,839 ) 4,585 Billings in excess of costs and estimated earnings — 8,319 22 — 8,341 Total current liabilities 151,408 578,608 11,984 (456,304 ) 285,696 Long-term debt 755,972 517,598 — (517,598 ) 755,972 Acquisition-related liabilities — 34,502 — — 34,502 Other noncurrent liabilities 706 110,974 57,580 (55,107 ) 114,153 Total liabilities 908,086 1,241,682 69,564 (1,029,009 ) 1,190,323 Redeemable noncontrolling interest — — — — — Redeemable members’ interest — — — — — Total stockholders’ equity/partners’ interest 789,999 551,194 49,808 (765,832 ) 625,169 Total liabilities, redeemable noncontrolling interest and member’s interest $ 1,698,085 $ 1,792,876 $ 119,372 $ (1,794,841 ) $ 1,815,492 Condensed Consolidating Balance Sheets December 27, 2014 Issuers Non- Wholly- Wholly- Non- Eliminations Consolidated Assets Current assets: Cash $ 10,837 $ 2 $ 695 $ 8,793 $ (7,112 ) $ 13,215 Accounts receivable, net 1 6,629 124,380 11,525 (1,233 ) 141,302 Intercompany receivables 376,344 4,095 30,539 4,052 (415,030 ) — Cost and estimated earnings in excess of billings — — 9,819 355 — 10,174 Inventories — 8,696 98,188 4,669 — 111,553 Other current assets 7,148 464 9,638 1,775 (1,853 ) 17,172 Total current assets 394,330 19,886 273,259 31,169 (425,228 ) 293,416 Property, plant and equipment, net 7,035 302,524 610,717 30,325 — 950,601 Goodwill — 23,124 340,969 55,177 — 419,270 Intangible assets, net — 542 14,245 2,860 — 17,647 Other assets 1,153,204 25,233 125,462 1,362 (1,256,418 ) 48,843 Total assets $ 1,554,569 $ 371,309 $ 1,364,652 $ 120,893 $ (1,681,646 ) $ 1,729,777 Liabilities, Redeemable Noncontrolling Interest and Member’s Interest Current liabilities: Current portion of debt $ 5,275 $ 1,273 $ 3,990 $ — $ (5,263 ) $ 5,275 Current portion of acquisition-related liabilities 166 — 18,236 — — 18,402 Accounts payable 3,655 6,845 65,018 4,569 (1,233 ) 78,854 Accrued expenses 37,101 10,178 59,477 3,705 (8,965 ) 101,496 Intercompany payables 162,728 4,052 245,416 2,834 (415,030 ) — Billings in excess of costs and estimated earnings — — 8,931 27 — 8,958 Total current liabilities 208,925 22,348 401,068 11,135 (430,491 ) 212,985 Long-term debt 1,059,642 153,318 480,599 — (633,917 ) 1,059,642 Acquisition-related liabilities — — 42,736 — — 42,736 Other noncurrent liabilities 796 24,787 65,479 57,736 (55,107 ) 93,691 Total liabilities 1,269,363 200,453 989,882 68,871 (1,119,515 ) 1,409,054 Redeemable noncontrolling interest — — — — 33,740 33,740 Redeemable members’ interest — 34,543 — — (34,543 ) — Total stockholders’ equity/partners’ interest 285,206 136,313 374,770 52,022 (561,328 ) 286,983 Total liabilities, redeemable noncontrolling interest and member’s interest $ 1,554,569 $ 371,309 $ 1,364,652 $ 120,893 $ (1,681,646 ) $ 1,729,777
Condensed Consolidating Statements of Operations	Condensed Consolidating Statements of Operations For the three months ended June 27, 2015 Issuers Wholly- Non- Eliminations Consolidated Revenue $ — $ 346,309 $ 23,702 $ (5,068 ) $ 364,943 Cost of revenue (excluding items shown separately below) — 240,637 13,601 (5,068 ) 249,170 General and administrative expenses 14,972 29,446 1,669 — 46,087 Depreciation, depletion, amortization and accretion 567 25,471 1,348 — 27,386 Operating (loss) income (15,539 ) 50,755 7,084 — 42,300 Other (income) expense, net (22,202 ) 2,761 10 50,406 30,975 Interest expense 6,352 13,990 909 (4,147 ) 17,104 Income from continuing operations before taxes 311 34,004 6,165 (46,259 ) (5,779 ) Income tax benefit (expense) — (5,625 ) 280 — (5,345 ) Income from continuing operations 311 39,629 5,885 (46,259 ) (434 ) Income from discontinued operations — (758 ) — — (758 ) Net income 311 40,387 5,885 (46,259 ) 324 Net income attributable to minority interest — — — 13 13 Net income attributable to member of Summit Materials, LLC $ 311 $ 40,387 $ 5,885 $ (46,272 ) $ 311 Comprehensive income attributable to member of Summit Materials, LLC $ 1,375 $ 40,387 $ 6,949 $ (47,336 ) $ 1,375 Condensed Consolidating Statements of Operations For the three months ended June 28, 2014 Issuers Non- Wholly- Wholly- Non- Eliminations Consolidated Revenue $ — $ 27,557 $ 287,307 $ 14,942 $ (5,511 ) $ 324,295 Cost of revenue (excluding items shown separately below) — 16,724 210,693 9,856 (5,511 ) 231,762 General and administrative expenses 10,002 1,900 25,080 290 — 37,272 Depreciation, depletion, amortization and accretion 338 3,703 17,020 278 — 21,339 Operating (loss) income (10,340 ) 5,230 34,514 4,518 — 33,922 Other (income) expense, net (29,100 ) (1,261 ) (1,360 ) (3 ) 31,027 (697 ) Interest expense 7,932 3,011 12,643 31 (1,966 ) 21,651 Income from continuing operations before taxes 10,828 3,480 23,231 4,490 (29,061 ) 12,968 Income tax benefit (expense) (1,427 ) — 563 — — (864 ) Income from continuing operations 12,255 3,480 22,668 4,490 (29,061 ) 13,832 Income from discontinued operations — — (369 ) — — (369 ) Net income 12,255 3,480 23,037 4,490 (29,061 ) 14,201 Net income attributable to minority interest — — — — 1,946 1,946 Net income attributable to member of Summit Materials, LLC $ 12,255 $ 3,480 $ 23,037 $ 4,490 $ (31,007 ) $ 12,255 Comprehensive income attributable to member of Summit Materials, LLC $ 12,255 $ 3,480 $ 23,037 $ 4,490 $ (31,007 ) $ 12,255 Condensed Consolidating Statements of Operations For the six months ended June 27, 2015 Issuers Wholly- Non- Eliminations Consolidated Revenue $ — $ 525,652 $ 57,349 $ (24,071 ) $ 558,930 Cost of revenue (excluding items shown separately below) — 391,864 39,646 (24,071 ) 407,439 General and administrative expenses 52,753 58,596 3,336 — 114,685 Depreciation, depletion, amortization and accretion 1,058 49,623 2,831 — 53,512 Operating (loss) income (53,811 ) 25,569 11,536 — (16,706 ) Other (income) expense, net 3,583 3,500 159 24,923 32,165 Interest expense 20,150 30,045 1,790 (10,772 ) 41,213 Income from continuing operations before taxes (77,544 ) (7,976 ) 9,587 (14,151 ) (90,084 ) Income tax benefit (expense) — (10,163 ) 350 — (9,813 ) Income from continuing operations (77,544 ) 2,187 9,237 (14,151 ) (80,271 ) Income from discontinued operations — (758 ) — — (758 ) Net income (77,544 ) 2,945 9,237 (14,151 ) (79,513 ) Net income attributable to minority interest — — — (1,969 ) (1,969 ) Net income attributable to member of Summit Materials, LLC $ (77,544 ) $ 2,945 $ 9,237 $ (12,182 ) $ (77,544 ) Comprehensive income attributable to member of Summit Materials, LLC $ (82,779 ) $ 2,945 $ 4,002 $ (6,947 ) $ (82,779 ) Condensed Consolidating Statements of Operations For the six months ended June 28, 2014 Issuers Non- Wholly- Wholly- Non- Eliminations Consolidated Revenue $ — $ 35,264 $ 427,717 $ 21,274 $ (8,869 ) $ 475,386 Cost of revenue (excluding items shown separately below) — 27,626 328,318 13,362 (8,869 ) 360,437 General and administrative expenses 17,690 3,574 53,521 566 — 75,351 Depreciation, depletion, amortization and accretion 642 6,777 32,731 545 — 40,695 Operating (loss) income (18,332 ) (2,713 ) 13,147 6,801 — (1,097 ) Other expense (income), net 7,725 (1,358 ) (1,553 ) 45 (5,750 ) (891 ) Interest expense 13,668 5,857 24,415 56 (3,526 ) 40,470 (Loss) income from continuing operations before taxes (39,725 ) (7,212 ) (9,715 ) 6,700 9,276 (40,676 ) Income tax benefit (1,427 ) — (33 ) — — (1,460 ) (Loss) income from continuing operations (38,298 ) (7,212 ) (9,682 ) 6,700 9,276 (39,216 ) Income from discontinued operations — — (349 ) — — (349 ) Net (loss) income (38,298 ) (7,212 ) (9,333 ) 6,700 9,276 (38,867 ) Net loss attributable to noncontrolling interest — — — — (569 ) (569 ) Net (loss) income attributable to member of Summit Materials, LLC $ (38,298 ) $ (7,212 ) $ (9,333 ) $ 6,700 $ 9,845 $ (38,298 ) Comprehensive (loss) income attributable to member of Summit Materials, LLC $ (38,298 ) $ (6,394 ) $ (9,333 ) $ 6,700 $ 9,600 $ (37,725 )
Condensed Consolidating Statements of Cash Flows	Condensed Consolidating Statements of Cash Flows For the six months ended June 27, 2015 Issuers Wholly- Non- Eliminations Consolidated Net cash (used in) provided by operating activities $ (93,127 ) $ 6,775 $ 6,435 $ (167 ) $ (80,084 ) Cash flow from investing activities: Acquisitions, net of cash acquired — (15,863 ) — — (15,863 ) Purchase of property, plant and equipment (1,904 ) (40,969 ) (506 ) — (43,379 ) Proceeds from the sale of property, plant, and equipment — 5,989 50 — 6,039 Other — 610 — — 610 Net cash used for investing activities (1,904 ) (50,233 ) (456 ) — (52,593 ) Cash flow from financing activities: Proceeds from investment by member 397,975 — — — 397,975 Capital issuance costs (9,373 ) (9,373 ) Net proceeds from debt issuance 242,000 — — — 242,000 Loans received from and payments made on loans from other Summit Companies (169,065 ) 176,243 (5,116 ) (2,062 ) — Payments on long-term debt (349,980 ) (120,703 ) — 1,055 (469,628 ) Payments on acquisition-related liabilities (166 ) (11,804 ) — — (11,970 ) Financing costs (5,130 ) — — — (5,130 ) Distributions from partnership (11,842 ) — — — (11,842 ) Other — (167 ) 167 — Net cash provided by (used for) financing activities 94,419 43,569 (5,116 ) (840 ) 132,032 Net increase (decrease) in cash (612 ) 111 863 (1,007 ) (645 ) Cash — Beginning of period 10,837 697 8,793 (7,112 ) 13,215 Cash — End of period $ 10,225 $ 808 $ 9,656 $ (8,119 ) $ 12,570 Condensed Consolidating Statements of Cash Flows For the six months ended June 28, 2014 Issuers Non- Wholly- Wholly- Non- Eliminations Consolidated Net cash used in operating activities $ (18,665 ) $ (13,153 ) $ (13,412 ) $ 168 $ (818 ) $ (45,880 ) Cash flow from investing activities: Acquisitions, net of cash acquired (181,754 ) — (53,116 ) — — (234,870 ) Purchase of property, plant and equipment (2,428 ) (11,829 ) (34,666 ) (337 ) — (49,260 ) Proceeds from the sale of property, plant, and equipment — — 5,912 73 — 5,985 Other — — (409 ) — 1,166 757 Net cash (used for) provided by investing activities (184,182 ) (11,829 ) (82,279 ) (264 ) 1,166 (277,388 ) Cash flow from financing activities: Proceeds from investment by member 24,350 — 1,166 (1,166 ) 24,350 Net proceeds from debt issuance 424,750 — — — — 424,750 Loans received from and payments made on loans from other Summit Companies (123,441 ) 25,234 104,121 22 (5,936 ) — Payments on long-term debt (104,060 ) (254 ) (4,932 ) — — (109,246 ) Payments on acquisition-related liabilities (1,000 ) — (3,259 ) — — (4,259 ) Financing costs (6,354 ) — — — — (6,354 ) Other (88 ) — (1,000 ) — 1,000 (88 ) Net cash provided by (used for) financing activities 214,157 24,980 94,930 1,188 (6,102 ) 329,153 Net increase (decrease) in cash 11,310 (2 ) (761 ) 1,092 (5,754 ) 5,885 Cash — Beginning of period 10,375 9 3,442 3,631 (2,540 ) 14,917 Cash — End of period $ 21,685 $ 7 $ 2,681 $ 4,723 $ (8,294 ) $ 20,802

Summary of Organization and S34

Summary of Organization and Significant Accounting Policies - Additional Information (Detail)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2015USD ($)	Jun. 27, 2015USD ($)Customer$ / sharesshares	Jun. 28, 2014USD ($)Customer	Jun. 27, 2015USD ($)CustomerSegmentState$ / sharesshares	Jun. 28, 2014USD ($)Customer	Dec. 27, 2014USD ($)
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Number of operating segments | Segment				3
Date of incorporation				Sep. 23, 2014
Net proceeds from IPO				$ 460,000,000
Redeemable noncontrolling interest percentage		40.00%		40.00%
Number of customers accounted for more than 10% of total revenue | Customer		0	0	0	0
Number of operating states | State				17
Reductions recognized in contingent consideration		$ 0	$ 0	$ 0	$ 0
Aggregate consideration for acquiring noncontrolling interests				64,100,000
Cash consideration				35,000,000
Aggregate principal amount of non-interest bearing notes payable				15,000,000
Annual installments amount of non-interest bearing notes payable				2,500,000
Decrease in other assets (noncurrent)				$ (53,000)	$ (2,214,000)
Summit Materials, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Number of operating segments | Segment				3
Date of incorporation				Sep. 23, 2014
Redeemable noncontrolling interest percentage		40.00%		40.00%
Number of customers accounted for more than 10% of total revenue | Customer		0	0	0	0
Number of operating states | State				17
Reductions recognized in contingent consideration		$ 0	$ 0	$ 0	$ 0
Aggregate consideration for acquiring noncontrolling interests				64,100,000
Aggregate principal amount of non-interest bearing notes payable				15,000,000
Annual installments amount of non-interest bearing notes payable				2,500,000
Decrease in other assets (noncurrent)				(53,000)	$ (2,214,000)
Cash consideration				35,000,000
Accounting Standards Update (ASU) 2015-03 [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Decrease in other assets (noncurrent)				(11,800,000)
Decrease in long-term debt						$ (16,800,000)
Accounting Standards Update (ASU) 2015-03 [Member] | Summit Materials, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Decrease in other assets (noncurrent)				$ (11,800,000)
Decrease in long-term debt						(16,800,000)
Level 3 [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Discount rate				11.00%
Level 3 [Member] | Summit Materials, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Discount rate				11.00%
Variable Interest Entity, Primary Beneficiary [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Percentage of voting power				100.00%
Noncontrolling interest elimination percentage				72.20%
Continental Cement Company, L.L.C. [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Redeemable noncontrolling interest percentage		30.00%		30.00%
Continental Cement Company, L.L.C. [Member] | Summit Materials, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Redeemable noncontrolling interest percentage		30.00%		30.00%
Ohio Valley Asphalt, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Redeemable noncontrolling interest percentage		20.00%		20.00%
Ohio Valley Asphalt, LLC [Member] | Summit Materials, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Redeemable noncontrolling interest percentage		20.00%		20.00%
Common Class A [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Class A common shares | shares				1,029,183
Common Class A [Member] | Summit Materials, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Class A common shares | shares				1,029,183
Senior Notes [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Debt instrument, face amount		$ 336,800,000		$ 336,800,000		625,000,000
Senior Notes [Member] | Summit Materials, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Debt instrument, face amount		$ 336,800,000		$ 336,800,000		$ 625,000,000
Initial Public Offering [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Operations commenced date				Mar. 11, 2015
Net proceeds from IPO				$ 433,000,000
Initial Public Offering [Member] | Summit Materials, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Operations commenced date				Mar. 11, 2015
Net proceeds from IPO				$ 433,000,000
Initial Public Offering [Member] | Blackstone Management Partners L.L.C. [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Payment of termination fee to affiliates of Sponsors				13,800,000
Initial Public Offering [Member] | Blackstone Management Partners L.L.C. [Member] | Summit Materials, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Payment of termination fee to affiliates of Sponsors				$ 13,800,000
Initial Public Offering [Member] | Common Class A [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Class A common shares | shares				25,555,555
Class A Common stock offering price per share | $ / shares		$ 18		$ 18
Initial Public Offering [Member] | Common Class A [Member] | Summit Materials, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Class A common shares | shares				25,555,555
Class A Common stock offering price per share | $ / shares		$ 18		$ 18
Initial Public Offering [Member] | Senior Notes [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Senior notes, aggregate principal amount redeemed		$ 288,200,000		$ 288,200,000
Senior notes, interest rate		10.50%		10.50%
Senior notes, redemption date				Jan. 31, 2020
Senior notes, redemption price percentage				100.00%
Debt instrument, face amount	$ 288,200,000	$ 288,200,000		$ 288,200,000
Debt Instrument, redemption premium	38,200,000			38,200,000
Accrued and unpaid interest		5,200,000		5,200,000
Initial Public Offering [Member] | Senior Notes [Member] | Summit Materials, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Senior notes, aggregate principal amount redeemed		$ 288,200,000		$ 288,200,000
Senior notes, interest rate		10.50%		10.50%
Senior notes, redemption date				Jan. 31, 2020
Senior notes, redemption price percentage				100.00%
Debt instrument, face amount	288,200,000	$ 288,200,000		$ 288,200,000
Debt Instrument, redemption premium	$ 38,200,000			38,200,000
Accrued and unpaid interest		$ 5,200,000		$ 5,200,000
Class B Units [Member] | Initial Public Offering [Member] | Continental Cement Company, L.L.C. [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Class B capital units purchased | shares		71,428,571		71,428,571
Class B Units [Member] | Initial Public Offering [Member] | Continental Cement Company, L.L.C. [Member] | Summit Materials, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Class B capital units purchased | shares		71,428,571		71,428,571
Sales [Member] | Customer Concentration Risk [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Customer accounted revenue		10.00%	10.00%	10.00%	10.00%
Sales [Member] | Customer Concentration Risk [Member] | Summit Materials, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Customer accounted revenue		10.00%	10.00%	10.00%	10.00%

Summary of Organization and S35

Summary of Organization and Significant Accounting Policies - Schedule of Contingent Consideration Obligations Measured at Fair Value (Detail) - USD ($) $ in Thousands	Jun. 27, 2015	Dec. 27, 2014
Business Acquisition, Contingent Consideration [Line Items]
Current portion of contingent consideration	$ 4,486	$ 2,375
Contingent consideration	4,193	5,379
Summit Materials, LLC [Member]
Business Acquisition, Contingent Consideration [Line Items]
Current portion of contingent consideration	4,486	2,375
Contingent consideration	$ 4,193	$ 5,379

Summary of Organization and S36

Summary of Organization and Significant Accounting Policies - Schedule of Carrying Value and Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 27, 2015	Dec. 27, 2014
Debt Instrument [Line Items]
Long-term debt, Carrying Value	$ 761,247	$ 1,064,917
Summit Materials, LLC [Member]
Debt Instrument [Line Items]
Long-term debt, Carrying Value	761,247	1,064,917
Level 2 [Member]
Debt Instrument [Line Items]
Long-term debt, Fair Value	780,155	1,101,873
Long-term debt, Carrying Value	827,247	1,064,917
Level 2 [Member] | Summit Materials, LLC [Member]
Debt Instrument [Line Items]
Long-term debt, Fair Value	780,155	1,101,873
Long-term debt, Carrying Value	827,247	1,064,917
Level 3 [Member]
Debt Instrument [Line Items]
Current portion of deferred consideration and noncompete obligations, Fair Value	17,909	16,027
Long term portion of deferred consideration and noncompete obligations, Fair Value	38,676	37,357
Current portion of deferred consideration and noncompete obligations, Carrying Value	17,909	16,027
Long term portion of deferred consideration and noncompete obligations, Carrying Value	38,676	37,357
Level 3 [Member] | Summit Materials, LLC [Member]
Debt Instrument [Line Items]
Current portion of deferred consideration and noncompete obligations, Fair Value	15,409	16,027
Long term portion of deferred consideration and noncompete obligations, Fair Value	30,309	37,357
Current portion of deferred consideration and noncompete obligations, Carrying Value	15,409	16,027
Long term portion of deferred consideration and noncompete obligations, Carrying Value	$ 30,309	$ 37,357

Summary of Organization and S37

Summary of Organization and Significant Accounting Policies - Schedule of Carrying Value and Fair Value of Financial Instruments (Parenthetical) (Detail) - USD ($) $ in Thousands	Jun. 27, 2015	Dec. 27, 2014
Debt Instrument [Line Items]
Current portion of debt	$ 5,300	$ 5,300
Remaining borrowing capacity	66,000
Summit Materials, LLC [Member]
Debt Instrument [Line Items]
Current portion of debt	5,300	$ 5,300
Remaining borrowing capacity	66,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Remaining borrowing capacity	66,000
Revolving Credit Facility [Member] | Summit Materials, LLC [Member]
Debt Instrument [Line Items]
Remaining borrowing capacity	$ 66,000

Reorganization - Additional Inf

Reorganization - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
	Mar. 28, 2015	Jun. 27, 2015
Reorganization Items [Line Items]
Number of LP Units outstanding		69,007,297
Vesting period of leverage restoration options		4 years
Summit Materials, LLC [Member]
Reorganization Items [Line Items]
Number of LP Units outstanding		69,007,297
General and Administrative Expense Costs [Member]
Reorganization Items [Line Items]
Modification charge recognized in general and administrative costs	$ 14.5
General and Administrative Expense Costs [Member] | Summit Materials, LLC [Member]
Reorganization Items [Line Items]
Modification charge recognized in general and administrative costs	$ 14.5
Common Class A-2 [Member]
Reorganization Items [Line Items]
Number of LP Units outstanding		0
Common Class A [Member]
Reorganization Items [Line Items]
Class A common shares		1,029,183
Common Class A [Member] | Summit Materials, LLC [Member]
Reorganization Items [Line Items]
Class A common shares		1,029,183
Common Class A [Member] | 2015 Omnibus Equity Incentive Plan [Member]
Reorganization Items [Line Items]
Number of class A common stock issued under the Omnibus Incentive Plan		240,000
Exercise price per share under the Omnibus Incentive Plan		$ 18
Share-based Compensation Award, Tranche One [Member] | 2015 Omnibus Equity Incentive Plan [Member]
Reorganization Items [Line Items]
Percentage of performance-vesting options		25.00%
Initial Public Offering [Member] | Common Class A [Member]
Reorganization Items [Line Items]
Class A common shares		25,555,555
Class A Common stock offering price per share		$ 18
Initial Public Offering [Member] | Common Class A [Member] | Summit Materials, LLC [Member]
Reorganization Items [Line Items]
Class A common shares		25,555,555
Class A Common stock offering price per share		$ 18
Class C Units [Member] | Common Class A [Member]
Reorganization Items [Line Items]
Class A common shares		160,333
Class C Units [Member] | Common Class A [Member] | Summit Materials, LLC [Member]
Reorganization Items [Line Items]
Class A common shares		160,333
Class D Units [Member] | Common Class A [Member]
Reorganization Items [Line Items]
Class A common shares		4,358,842
Class D Units [Member] | Common Class A [Member] | Summit Materials, LLC [Member]
Reorganization Items [Line Items]
Class A common shares		4,358,842

Accounts Receivable, Net - Summ

Accounts Receivable, Net - Summary of Accounts Receivable, Net (Detail) - USD ($) $ in Thousands	Jun. 27, 2015	Dec. 27, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 154,678	$ 131,060
Retention receivables	11,119	12,053
Receivables from related parties	629	333
Accounts receivable	166,426	143,446
Less: Allowance for doubtful accounts	(2,367)	(2,144)
Accounts receivable, net	164,059	141,302
Summit Materials, LLC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	154,678	131,060
Retention receivables	11,119	12,053
Receivables from related parties	629	333
Accounts receivable	166,426	143,446
Less: Allowance for doubtful accounts	(2,367)	(2,144)
Accounts receivable, net	$ 164,059	$ 141,302

Inventories - Components of Inv

Inventories - Components of Inventories (Detail) - USD ($) $ in Thousands	Jun. 27, 2015	Dec. 27, 2014
Inventory [Line Items]
Aggregate stockpiles	$ 91,036	$ 88,211
Finished goods	16,791	8,826
Work in process	1,882	1,801
Raw materials	18,708	12,715
Total	128,417	111,553
Summit Materials, LLC [Member]
Inventory [Line Items]
Aggregate stockpiles	91,036	88,211
Finished goods	16,791	8,826
Work in process	1,882	1,801
Raw materials	18,708	12,715
Total	$ 128,417	$ 111,553

Accrued Expenses - Components o

Accrued Expenses - Components of Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 27, 2015	Dec. 27, 2014
Schedule Of Accrued Expenses [Line Items]
Interest	$ 19,908	$ 32,475
Payroll and benefits	17,733	20,326
Capital lease obligations	18,400	17,530
Insurance	11,780	11,402
Non-income taxes	6,464	5,520
Professional fees	5,142	3,299
Other	11,351	10,944
Total	90,778	101,496
Summit Materials, LLC [Member]
Schedule Of Accrued Expenses [Line Items]
Interest	19,908	32,475
Payroll and benefits	17,733	20,326
Capital lease obligations	18,400	17,530
Insurance	11,780	11,402
Non-income taxes	6,464	5,520
Professional fees	5,142	3,299
Other	11,351	10,944
Total	$ 90,778	$ 101,496

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Detail) - USD ($) $ in Thousands	Jun. 27, 2015	Dec. 27, 2014
Debt Instrument [Line Items]
Revolving credit facility	$ 66,000
Long-term debt:
Revolving credit facility	66,000
Long-term debt, total	761,247	$ 1,064,917
Current portion of long-term debt	5,275	5,275
Long-term debt	755,972	1,059,642
Credit Facility [Member]
Long-term debt:
Long-term debt, total	411,546	413,369
Senior Notes [Member]
Long-term debt:
Long-term debt, total	349,701	651,548
Summit Materials, LLC [Member]
Debt Instrument [Line Items]
Revolving credit facility	66,000
Long-term debt:
Revolving credit facility	66,000
Long-term debt, total	761,247	1,064,917
Current portion of long-term debt	5,275	5,275
Long-term debt	755,972	1,059,642
Summit Materials, LLC [Member] | Credit Facility [Member]
Long-term debt:
Long-term debt, total	411,546	413,369
Summit Materials, LLC [Member] | Senior Notes [Member]
Long-term debt:
Long-term debt, total	$ 349,701	$ 651,548

Debt - Schedule of Debt (Parent

Debt - Schedule of Debt (Parenthetical) (Detail) - USD ($)	Jun. 27, 2015	Dec. 27, 2014
Senior Notes [Member]
Debt Instrument [Line Items]
Long-term debt, face value	$ 336,800,000	$ 625,000,000
Original issuance discount	12,900,000	26,500,000
Summit Materials, LLC [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term debt, face value	336,800,000	625,000,000
Original issuance discount	12,900,000	26,500,000
Credit Facility [Member]
Debt Instrument [Line Items]
Long-term debt, face value	413,600,000	415,700,000
Original issuance discount	2,100,000	2,300,000
Credit Facility [Member] | Summit Materials, LLC [Member]
Debt Instrument [Line Items]
Long-term debt, face value	413,600,000	415,700,000
Original issuance discount	$ 2,100,000	$ 2,300,000

Debt - Schedule of Contractual

Debt - Schedule of Contractual Payments of Long-Term Debt (Detail) - USD ($) $ in Thousands	Jun. 27, 2015	Dec. 27, 2014
Long Term Debt Maturities Repayments Of Principal [Line Items]
2015 (six months)	$ 3,165
2,016	4,220
2,017	4,220
2,018	3,165
2,019	398,790
2,020	336,800
Total	750,360
Plus: Original issue net premium	10,887
Total debt	761,247	$ 1,064,917
Summit Materials, LLC [Member]
Long Term Debt Maturities Repayments Of Principal [Line Items]
2015 (six months)	3,165
2,016	4,220
2,017	4,220
2,018	3,165
2,019	398,790
2,020	336,800
Total	750,360
Plus: Original issue net premium	10,887
Total debt	$ 761,247	$ 1,064,917

Debt - Additional Information (

Debt - Additional Information (Detail) CAD in Millions

Mar. 17, 2015USD ($)

Jan. 15, 2015CAD

Apr. 30, 2015USD ($)

Jun. 27, 2015USD ($)

Jun. 28, 2014USD ($)

Jun. 27, 2015USD ($)

Jun. 28, 2014USD ($)

Mar. 16, 2015USD ($)

Mar. 11, 2015USD ($)

Dec. 27, 2014USD ($)

Sep. 08, 2014USD ($)

Jan. 17, 2014USD ($)

Debt Instrument [Line Items]

Write off of deferred financing fees

$ 5,109,000

Proceeds from issuance of debt

242,000,000

$ 424,750,000

Premium of debt instrument

$ 10,887,000

10,887,000

Financing fees

(30,873,000)

(31,672,000)

Outstanding letters of credit

66,000,000

66,000,000

Interest expense

$ 14,800,000

$ 19,300,000

$ 36,800,000

36,500,000

Prime Rate [Member] | COLOMBIA

Debt Instrument [Line Items]

Basis spread on variable rate

0.20%

Prime Rate [Member] | CANADA

Debt Instrument [Line Items]

Basis spread on variable rate

0.90%

Senior Secured Credit Facilities [Member] | Maximum [Member]

Debt Instrument [Line Items]

First lien leverage ratio

4.51

Senior Secured Credit Facilities [Member] | Minimum [Member]

Debt Instrument [Line Items]

Interest coverage ratio, maximum

1.85

Revolving Credit Facility [Member]

Debt Instrument [Line Items]

Line of credit facility, maximum borrowing capacity

$ 235,000,000

$ 150,000,000

Revolving credit facility, maturity date

Mar. 11, 2020

Effective interest rate

3.60%

3.60%

Outstanding letters of credit

$ 66,000,000

$ 66,000,000

Revolving Credit Facility [Member] | COLOMBIA

Debt Instrument [Line Items]

Revolving credit commitment | CAD

CAD 6

Revolving Credit Facility [Member] | CANADA

Debt Instrument [Line Items]

Revolving credit commitment | CAD

0.5

Revolving Credit Facility [Member] | Mainland [Member]

Debt Instrument [Line Items]

Revolving credit commitment | CAD

CAD 0.4

Revolving Credit Facility [Member] | Federal Funds Effective Rate [Member]

Debt Instrument [Line Items]

Basis spread on variable rate

0.50%

Revolving Credit Facility [Member] | Libor Plus Rate [Member]

Debt Instrument [Line Items]

Basis spread on variable rate

1.00%

Revolving Credit Facility [Member] | Base Rate [Member]

Debt Instrument [Line Items]

Interest rate - Revolving credit commitments, minimum interest rate

2.50%

Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]

Debt Instrument [Line Items]

Basis spread on variable rate

3.50%

Letter of Credit [Member]

Debt Instrument [Line Items]

Line of credit facility, maximum borrowing capacity

144,800,000

$ 144,800,000

Outstanding letters of credit

24,200,000

24,200,000

Senior Notes [Member]

Debt Instrument [Line Items]

Debt instrument, face amount

336,800,000

336,800,000

$ 625,000,000

Charges on redemption

$ 31,300,000

Write off of deferred financing fees

4,700,000

Net benefit from the write-off the original issuance premium and discount

11,600,000

Senior Notes [Member] | Initial Public Offering [Member]

Debt Instrument [Line Items]

Debt instrument, face amount

288,200,000

288,200,000

288,200,000

Debt Instrument, redemption premium

38,200,000

38,200,000

Summit Materials, LLC [Member]

Debt Instrument [Line Items]

Write off of deferred financing fees

5,109,000

Proceeds from issuance of debt

242,000,000

424,750,000

Premium of debt instrument

10,887,000

10,887,000

Financing fees

(30,873,000)

(31,672,000)

Outstanding letters of credit

66,000,000

66,000,000

Interest expense

14,800,000

$ 19,300,000

36,800,000

$ 36,500,000

Summit Materials, LLC [Member] | Prime Rate [Member] | COLOMBIA

Debt Instrument [Line Items]

Basis spread on variable rate

0.20%

Summit Materials, LLC [Member] | Prime Rate [Member] | CANADA

Debt Instrument [Line Items]

Basis spread on variable rate

0.90%

Summit Materials, LLC [Member] | Senior Secured Credit Facilities [Member]

Debt Instrument [Line Items]

Debt instrument, face amount

422,000,000

$ 422,000,000

Quarterly principal repayments percentage

0.25%

Frequency of periodic payment

Term debt are due on the last business day of each March, June, September and December.

Maturity date

Jan. 30, 2019

Summit Materials, LLC [Member] | Senior Secured Credit Facilities [Member] | Maximum [Member]

Debt Instrument [Line Items]

First lien leverage ratio

4.51

Summit Materials, LLC [Member] | Revolving Credit Facility [Member]

Debt Instrument [Line Items]

Debt instrument, face amount

235,000,000

$ 235,000,000

Line of credit facility, maximum borrowing capacity

$ 235,000,000

$ 150,000,000

Revolving credit facility, maturity date

Mar. 11, 2020

Outstanding letters of credit

$ 66,000,000

$ 66,000,000

Revolving credit commitment | CAD

CAD 0.4

Summit Materials, LLC [Member] | Revolving Credit Facility [Member] | COLOMBIA

Debt Instrument [Line Items]

Revolving credit commitment | CAD

6

Summit Materials, LLC [Member] | Revolving Credit Facility [Member] | CANADA

Debt Instrument [Line Items]

Revolving credit commitment | CAD

CAD 0.5

Summit Materials, LLC [Member] | Revolving Credit Facility [Member] | Federal Funds Effective Rate [Member]

Debt Instrument [Line Items]

Basis spread on variable rate

0.50%

Summit Materials, LLC [Member] | Revolving Credit Facility [Member] | Libor Plus Rate [Member]

Debt Instrument [Line Items]

Basis spread on variable rate

1.00%

Effective interest rate

3.60%

3.60%

Summit Materials, LLC [Member] | Revolving Credit Facility [Member] | Base Rate [Member]

Debt Instrument [Line Items]

Interest rate - Revolving credit commitments, minimum interest rate

2.50%

Summit Materials, LLC [Member] | Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]

Debt Instrument [Line Items]

Basis spread on variable rate

3.50%

Summit Materials, LLC [Member] | Letter of Credit [Member]

Debt Instrument [Line Items]

Line of credit facility, maximum borrowing capacity

$ 144,800,000

$ 144,800,000

Outstanding letters of credit

24,200,000

24,200,000

Summit Materials, LLC [Member] | Term Loan Credit Facility [Member]

Debt Instrument [Line Items]

Debt instrument, face amount

422,000,000

$ 422,000,000

Summit Materials, LLC [Member] | Interest Coverage Ratio Fiscal Quarter Started January 1, 2013 Through December 31, 2014 [Member] | Senior Secured Credit Facilities [Member] | Minimum [Member]

Debt Instrument [Line Items]

Interest coverage ratio, maximum

1.70

Summit Materials, LLC [Member] | Interest Coverage Ratio After December 31, 2014 [Member] | Senior Secured Credit Facilities [Member] | Minimum [Member]

Debt Instrument [Line Items]

Interest coverage ratio, maximum

1.85

Summit Materials, LLC [Member] | Senior Notes [Member]

Debt Instrument [Line Items]

Debt instrument, face amount

336,800,000

$ 336,800,000

$ 625,000,000

Charges on redemption

31,900,000

Write off of deferred financing fees

5,300,000

Net benefit from the write-off the original issuance premium and discount

11,600,000

Summit Materials, LLC [Member] | Senior Notes [Member] | Initial Public Offering [Member]

Debt Instrument [Line Items]

Debt instrument, face amount

288,200,000

288,200,000

288,200,000

Debt Instrument, redemption premium

$ 38,200,000

38,200,000

Summit Materials And Summit Materials Finance Corp [Member] | 2020 Notes Additional [Member]

Debt Instrument [Line Items]

Debt instrument, face amount

$ 115,000,000

$ 260,000,000

Proceeds from issuance of debt

409,300,000

Premium of debt instrument

34,300,000

34,300,000

Summit Materials And Summit Materials Finance Corp [Member] | Existing Secured Notes [Member]

Debt Instrument [Line Items]

Debt instrument, face amount

$ 250,000,000

$ 250,000,000

Debt - Summary of Activity for

Debt - Summary of Activity for Deferred Financing Fees (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 27, 2015	Jun. 28, 2014
Deferred Financing Cost [Line Items]
Beginning balance	$ 17,215	$ 11,485
Loan origination fees	5,130	6,309
Amortization	(1,701)	(1,544)
Write off of deferred financing fees	(5,109)
Ending balance	15,535	16,250
Summit Materials, LLC [Member]
Deferred Financing Cost [Line Items]
Beginning balance	17,215	11,485
Loan origination fees	5,130	6,309
Amortization	(1,701)	(1,544)
Write off of deferred financing fees	(5,109)
Ending balance	$ 15,535	$ 16,250

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 31, 2015	Jun. 27, 2015	Jun. 28, 2014	Jun. 27, 2015	Jun. 28, 2014	Dec. 27, 2014
Income Taxes [Line Items]
Liabilities for uncertain tax positions		$ 0		$ 0		$ 0
Interest and penalties recognized in income tax expense		0	$ 0	0	$ 0
Deferred tax assets, net		50,500,000		50,500,000
Deferred tax liability, intangible assets		69,000,000		69,000,000
Deferred tax liability, book aggregate reserves		6,900,000		6,900,000
Deferred tax liability, fixed assets		10,900,000		10,900,000
Provision for income taxes		(5,345,000)	(864,000)	$ (9,813,000)	(1,460,000)
Percentage of benefits to be paid on tax receivable agreement				85.00%
Total distributions declared		16,400,000		$ 16,400,000
Distributions paid in cash to Summit Holdings' partners				11,842,000
Limited Liability Company [Member]
Income Taxes [Line Items]
Provision for income taxes		0		0
Subsequent Event [Member]
Income Taxes [Line Items]
Distributions paid in cash to Summit Holdings' partners	$ 11,800,000
Distributions paid in cash to Summit Inc.	4,600,000
Summit Materials, LLC [Member]
Income Taxes [Line Items]
Liabilities for uncertain tax positions		0		0		$ 0
Interest and penalties recognized in income tax expense		0	0	0	0
Provision for income taxes		(5,345,000)	$ (864,000)	(9,813,000)	$ (1,460,000)
Total distributions declared		$ 16,400,000		16,400,000
Distributions paid in cash to Summit Holdings' partners				$ 11,842,000
Summit Materials, LLC [Member] | Subsequent Event [Member]
Income Taxes [Line Items]
Distributions paid in cash to Summit Holdings' partners	11,800,000
Distributions paid in cash to Summit Inc.	$ 4,600,000

Net Loss Per Share - Additional

Net Loss Per Share - Additional Information (Detail) - Jun. 27, 2015 - $ / shares	Total	Total	Total
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Basic and diluted earnings per share for discontinued operations	$ 0.01		$ 0.01
Common Class A [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Issuance of common stock, Shares		25,555,555	25,555,555
Stock issued in conjunction with the acquisition			1,029,183

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Basic to Diluted Loss Per Share (Detail) - Jun. 27, 2015 - USD ($) $ / shares in Units, $ in Thousands	Total	Total
Schedule Of Earnings Per Share [Line Items]
Net loss attributable to Summit Inc.	$ (205)	$ (10,356)
Add: Noncontrolling interest impact of LP Unit conversion		(958)
Diluted net loss attributable to Summit Inc.	$ (205)	$ (11,314)
Basic earnings per share	$ (0.01)	$ (0.39)
Add: weighted average of LP Units		1,826,152
Weighted average dilutive shares outstanding	26,584,738	28,410,890
Diluted earnings per share	$ (0.01)	$ (0.40)
Common Class A [Member]
Schedule Of Earnings Per Share [Line Items]
Weighted average shares of Class A shares outstanding	26,584,738	26,584,738
Basic earnings per share	$ (0.01)	$ (0.39)
Weighted average shares of Class A shares outstanding	26,584,738	26,584,738
Weighted average dilutive shares outstanding	26,584,738	28,410,890
Diluted earnings per share	$ (0.01)	$ (0.40)

Net Loss Per Share - Schedule50

Net Loss Per Share - Schedule of Basic to Diluted Loss Per Share (Parenthetical) (Detail)	6 Months Ended
	Jun. 27, 2015
Minimum [Member]
Schedule Of Earnings Per Share [Line Items]
Change in ownership percentage	27.80%
Maximum [Member]
Schedule Of Earnings Per Share [Line Items]
Change in ownership percentage	30.40%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Apr. 02, 2015	Jun. 27, 2015	Dec. 29, 2012	Dec. 31, 2011	Dec. 27, 2014
Loss Contingencies [Line Items]
Percentage of ownership interest in joint venture		40.00%
Amount funded for loss incurred by joint venture		$ 8.8	$ 4	$ 4.8
Accrual recorded in other noncurrent liabilities		4.3			$ 4.3
Value of damages sought	$ 29.4
Unapproved change orders and claims		1.4			3.9
Unapproved change orders within accounts receivable		1.2			1.2
Unapproved change orders within costs in excess of billings		$ 0.2			0.5
Unapproved change orders within other current assets					2.2
Summit Materials, LLC [Member]
Loss Contingencies [Line Items]
Percentage of ownership interest in joint venture		40.00%
Amount funded for loss incurred by joint venture		$ 8.8	$ 4	$ 4.8
Accrual recorded in other noncurrent liabilities		4.3			4.3
Value of damages sought	$ 29.4
Unapproved change orders and claims		1.4			3.9
Unapproved change orders within accounts receivable		1.2			1.2
Unapproved change orders within costs in excess of billings		$ 0.2			0.5
Unapproved change orders within other current assets					$ 2.2
Maximum [Member]
Loss Contingencies [Line Items]
Duration of commitments		1 year
Maximum [Member] | Summit Materials, LLC [Member]
Loss Contingencies [Line Items]
Duration of commitments		1 year

Supplemental Cash Flow Inform52

Supplemental Cash Flow Information - Schedule of Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 27, 2015	Jun. 28, 2014
Cash payments:
Interest	$ 50,646	$ 25,881
Income taxes	1,257	1,320
Non cash financing activities:
Purchase of noncontrolling interest in Continental Cement	(29,102)
Summit Materials, LLC [Member]
Cash payments:
Interest	50,646	25,881
Income taxes	1,257	$ 1,320
Non cash financing activities:
Purchase of noncontrolling interest in Continental Cement	$ (64,102)

Segment Information - Additiona

Segment Information - Additional Information (Detail)	6 Months Ended
	Jun. 27, 2015Segment
Segment Reporting Information [Line Items]
Number of operating segments	3
Summit Materials, LLC [Member]
Segment Reporting Information [Line Items]
Number of operating segments	3

Segment Information - Summary o

Segment Information - Summary of Financial Data for Company's Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2015	Jun. 28, 2014	Jun. 27, 2015	Jun. 28, 2014	Dec. 27, 2014
Segment Reporting Information [Line Items]
Total revenue	$ 364,943	$ 324,295	$ 558,930	$ 475,386
Adjusted EBITDA	69,584	55,958	64,609	40,489
Interest expense	17,395	21,651	41,504	40,470
Depreciation, depletion, amortization and accretion	27,386	21,339	53,512	40,695
Initial public offering costs			28,296
Loss on debt financings	30,873		31,672
(Loss) income from continuing operations before taxes	(6,070)	12,968	(90,375)	(40,676)
Total capital expenditures			43,379	49,260
Total depreciation, depletion, amortization and accretion	27,386	21,339	53,512	40,695
Total assets	1,815,492		1,815,492		$ 1,729,777
Summit Materials, LLC [Member]
Segment Reporting Information [Line Items]
Total revenue	364,943	324,295	558,930	475,386
Adjusted EBITDA	69,584	55,958	64,609	40,489
Interest expense	17,104	21,651	41,213	40,470
Depreciation, depletion, amortization and accretion	27,386	21,339	53,512	40,695
Initial public offering costs			28,296
Loss on debt financings	30,873		31,672
(Loss) income from continuing operations before taxes	(5,779)	12,968	(90,084)	(40,676)
Total capital expenditures			43,379	49,260
Total depreciation, depletion, amortization and accretion	27,386	21,339	53,512	40,695
Total assets	1,815,492		1,815,492		1,729,777
Operating Segments [Member]
Segment Reporting Information [Line Items]
Depreciation, depletion, amortization and accretion	26,817	21,002	52,454	40,053
Total capital expenditures			41,475	46,829
Total depreciation, depletion, amortization and accretion	26,817	21,002	52,454	40,053
Total assets	1,782,221		1,782,221		1,703,713
Operating Segments [Member] | Summit Materials, LLC [Member]
Segment Reporting Information [Line Items]
Depreciation, depletion, amortization and accretion	26,817	21,002	52,454	40,053
Total capital expenditures			41,475	46,829
Total depreciation, depletion, amortization and accretion	26,817	21,002	52,454	40,053
Total assets	1,782,221		1,782,221		1,703,713
Operating Segments [Member] | Aggregates [Member]
Segment Reporting Information [Line Items]
Total revenue	79,929	59,816	132,266	91,366
Operating Segments [Member] | Aggregates [Member] | Summit Materials, LLC [Member]
Segment Reporting Information [Line Items]
Total revenue	79,929	59,816	132,266	91,366
Operating Segments [Member] | Cement [Member]
Segment Reporting Information [Line Items]
Total revenue	30,177	27,557	41,996	35,264
Operating Segments [Member] | Cement [Member] | Summit Materials, LLC [Member]
Segment Reporting Information [Line Items]
Total revenue	30,177	27,557	41,996	35,264
Operating Segments [Member] | Ready Mixed Concrete [Member]
Segment Reporting Information [Line Items]
Total revenue	89,309	71,389	159,397	113,769
Operating Segments [Member] | Ready Mixed Concrete [Member] | Summit Materials, LLC [Member]
Segment Reporting Information [Line Items]
Total revenue	89,309	71,389	159,397	113,769
Operating Segments [Member] | Asphalt [Member]
Segment Reporting Information [Line Items]
Total revenue	85,329	74,686	106,243	99,082
Operating Segments [Member] | Asphalt [Member] | Summit Materials, LLC [Member]
Segment Reporting Information [Line Items]
Total revenue	85,329	74,686	106,243	99,082
Operating Segments [Member] | Paving And Related Services [Member]
Segment Reporting Information [Line Items]
Total revenue	137,330	144,911	181,229	200,768
Operating Segments [Member] | Paving And Related Services [Member] | Summit Materials, LLC [Member]
Segment Reporting Information [Line Items]
Total revenue	137,330	144,911	181,229	200,768
Operating Segments [Member] | West Region [Member]
Segment Reporting Information [Line Items]
Total revenue	208,068	172,236	335,742	267,130
Adjusted EBITDA	39,497	30,750	51,366	32,541
Depreciation, depletion, amortization and accretion	12,634	7,667	24,722	14,414
Total capital expenditures			18,037	17,924
Total depreciation, depletion, amortization and accretion	12,634	7,667	24,722	14,414
Total assets	824,892		824,892		777,981
Operating Segments [Member] | West Region [Member] | Summit Materials, LLC [Member]
Segment Reporting Information [Line Items]
Total revenue	208,068	172,236	335,742	267,130
Adjusted EBITDA	39,497	30,750	51,366	32,541
Depreciation, depletion, amortization and accretion	12,634	7,667	24,722	14,414
Total capital expenditures			18,037	17,924
Total depreciation, depletion, amortization and accretion	12,634	7,667	24,722	14,414
Total assets	824,892		824,892		777,981
Operating Segments [Member] | Central Region [Member]
Segment Reporting Information [Line Items]
Total revenue	117,920	109,117	174,529	156,659
Adjusted EBITDA	35,518	28,823	36,228	28,400
Depreciation, depletion, amortization and accretion	11,348	9,504	21,420	18,351
Total capital expenditures			15,920	23,372
Total depreciation, depletion, amortization and accretion	11,348	9,504	21,420	18,351
Total assets	726,976		726,976		704,134
Operating Segments [Member] | Central Region [Member] | Summit Materials, LLC [Member]
Segment Reporting Information [Line Items]
Total revenue	117,920	109,117	174,529	156,659
Adjusted EBITDA	35,518	28,823	36,228	28,400
Depreciation, depletion, amortization and accretion	11,348	9,504	21,420	18,351
Total capital expenditures			15,920	23,372
Total depreciation, depletion, amortization and accretion	11,348	9,504	21,420	18,351
Total assets	726,976		726,976		704,134
Operating Segments [Member] | East Region [Member]
Segment Reporting Information [Line Items]
Total revenue	38,955	42,942	48,659	51,597
Adjusted EBITDA	9,580	7,932	1,713	(1,406)
Depreciation, depletion, amortization and accretion	2,835	3,831	6,312	7,288
Total capital expenditures			7,518	5,533
Total depreciation, depletion, amortization and accretion	2,835	3,831	6,312	7,288
Total assets	230,353		230,353		221,598
Operating Segments [Member] | East Region [Member] | Summit Materials, LLC [Member]
Segment Reporting Information [Line Items]
Total revenue	38,955	42,942	48,659	51,597
Adjusted EBITDA	9,580	7,932	1,713	(1,406)
Depreciation, depletion, amortization and accretion	2,835	3,831	6,312	7,288
Total capital expenditures			7,518	5,533
Total depreciation, depletion, amortization and accretion	2,835	3,831	6,312	7,288
Total assets	230,353		230,353		221,598
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenue	(57,131)	(54,064)	(62,201)	(64,863)
Intersegment Eliminations [Member] | Summit Materials, LLC [Member]
Segment Reporting Information [Line Items]
Total revenue	(57,131)	(54,064)	(62,201)	(64,863)
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	(15,011)	(11,547)	(24,698)	(19,046)
Depreciation, depletion, amortization and accretion	569	337	1,058	642
Total capital expenditures			1,904	2,431
Total depreciation, depletion, amortization and accretion	569	337	1,058	642
Total assets	33,271		33,271		26,064
Corporate and Other [Member] | Summit Materials, LLC [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	(15,011)	(11,547)	(24,698)	(19,046)
Depreciation, depletion, amortization and accretion	569	337	1,058	642
Total capital expenditures			1,904	2,431
Total depreciation, depletion, amortization and accretion	569	$ 337	1,058	$ 642
Total assets	$ 33,271		$ 33,271		$ 26,064

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail)	Apr. 16, 2015USD ($)Business	Sep. 30, 2014USD ($)	Jan. 31, 2014USD ($)	Mar. 11, 2015USD ($)	Mar. 17, 2015USD ($)	Jun. 28, 2014USD ($)	Mar. 29, 2014USD ($)	Jun. 27, 2015USD ($)	Jun. 28, 2014USD ($)	Dec. 27, 2014USD ($)
Related Party Transaction [Line Items]
Transaction fees paid						$ 600,000			$ 2,300,000
Related party transactions		$ 5,750,000	$ 13,000,000
Assets sold to related party									2,300,000
Summit Materials, LLC [Member]
Related Party Transaction [Line Items]
Transaction fees paid						600,000			2,300,000
Related party transactions		$ 5,750,000	$ 13,000,000
Assets sold to related party									2,300,000
Blackstone Management Partners L.L.C. [Member]
Related Party Transaction [Line Items]
Consideration of Consolidated profit								$300,000 or 2.0% which ever is higher
Payment for services								$ 300,000
Management fees incurred					$ 1,000,000	1,300,000			2,300,000
Percentage transaction fee on value of entity acquired								1.00%
Consideration paid / received on assets acquired / disposed								1.00%
Management fee agreement termination date								Mar. 17, 2015
Management fee paid as of termination								$ 13,800,000
Blackstone Management Partners L.L.C. [Member] | Summit Materials, LLC [Member]
Related Party Transaction [Line Items]
Consideration of Consolidated profit								$300,000 or 2.0% which ever is higher
Payment for services								$ 300,000
Management fees incurred					$ 1,000,000	1,300,000			2,300,000
Percentage transaction fee on value of entity acquired								1.00%
Consideration paid / received on assets acquired / disposed								1.00%
Management fee agreement termination date								Mar. 17, 2015
Management fee paid as of termination								$ 13,800,000
Blackstone and Affiliates [Member]
Related Party Transaction [Line Items]
Management fee paid as of termination								13,400,000
Blackstone and Affiliates [Member] | Summit Materials, LLC [Member]
Related Party Transaction [Line Items]
Management fee paid as of termination								13,400,000
Silverhawk Summit LP [Member]
Related Party Transaction [Line Items]
Management fee paid as of termination								400,000
Silverhawk Summit LP [Member] | Summit Materials, LLC [Member]
Related Party Transaction [Line Items]
Management fee paid as of termination								$ 400,000
Continental Cement Company, L.L.C. [Member]
Related Party Transaction [Line Items]
Sales to related parties				$ 1,400,000		4,500,000			6,200,000
Accounts receivables due from related parties										$ 200,000
Non controlling interest owned							$ 700,000
Continental Cement Company, L.L.C. [Member] | Summit Materials, LLC [Member]
Related Party Transaction [Line Items]
Sales to related parties				$ 1,400,000		$ 4,500,000			$ 6,200,000
Accounts receivables due from related parties										$ 200,000
Non controlling interest owned							$ 700,000
Lafarge North America Inc [Member] | Davenport Acquisition [Member]
Related Party Transaction [Line Items]
Aggregate cash consideration to be paid	$ 450,000,000
Purchase agreement date for assets acquired	Apr. 16, 2015
Number of cement distribution terminals acquired | Business	7
Purchase price due	$ 370,000,000
Purchase price remaining before cutoff date	$ 80,000,000
Cut off date for purchase price	Dec. 31, 2015
Lafarge North America Inc [Member] | Bettendorf Iowa [Member]
Related Party Transaction [Line Items]
Number of cement distribution terminals acquired | Business	1
Lafarge North America Inc [Member] | Summit Materials, LLC [Member] | Davenport Acquisition [Member]
Related Party Transaction [Line Items]
Aggregate cash consideration to be paid	$ 450,000,000
Purchase agreement date for assets acquired	Apr. 16, 2015
Number of cement distribution terminals acquired | Business	7
Purchase price due	$ 370,000,000
Purchase price remaining before cutoff date	$ 80,000,000
Cut off date for purchase price	Dec. 31, 2015
Lafarge North America Inc [Member] | Summit Materials, LLC [Member] | Bettendorf Iowa [Member]
Related Party Transaction [Line Items]
Number of cement distribution terminals acquired | Business	1
Blackstone Capital Partners VI Limited Partnership [Member] | Davenport Acquisition [Member]
Related Party Transaction [Line Items]
Equity commitment financing	$ 90,000,000
Deferred purchase price associated with acquisition	80,000,000
Commitment fee paid	1,800,000
Blackstone Capital Partners VI Limited Partnership [Member] | Summit Materials, LLC [Member] | Davenport Acquisition [Member]
Related Party Transaction [Line Items]
Equity commitment financing	90,000,000
Deferred purchase price associated with acquisition	80,000,000
Commitment fee paid	$ 1,800,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Aug. 05, 2015	Jul. 17, 2015	Jul. 08, 2015	Jun. 27, 2015	Jun. 28, 2014
Subsequent Event [Line Items]
Loans borrowed under term loan facility				$ 66,000
Amount paid for purchase of assets				43,379	$ 49,260
Summit Materials, LLC [Member]
Subsequent Event [Line Items]
Loans borrowed under term loan facility				66,000
Amount paid for purchase of assets				$ 43,379	$ 49,260
Subsequent Event [Member]
Subsequent Event [Line Items]
Number of newly-issued shares purchased from Summit Holdings	3,750,000
Number of shares purchased from outstanding shares of Summit Holdings	15,750,000
Amount paid for purchase of assets		$ 370,000
Refinance existing senior secured term loan facility		183,000
Amount of purchase price due		$ 80,000
Percentage of interest payable		7.50%
Subsequent Event [Member] | Summit Materials, LLC [Member]
Subsequent Event [Line Items]
Number of newly-issued shares purchased from Summit Holdings	3,750,000
Number of shares purchased from outstanding shares of Summit Holdings	15,750,000
Amount paid for purchase of assets		$ 370,000
Refinance existing senior secured term loan facility		183,000
Amount of purchase price due		$ 80,000
Percentage of interest payable		7.50%
Subsequent Event [Member] | Term Loan Credit Facility [Member]
Subsequent Event [Line Items]
Loans borrowed under term loan facility		$ 650,000
Subsequent Event [Member] | Term Loan Credit Facility [Member] | Summit Materials, LLC [Member]
Subsequent Event [Line Items]
Loans borrowed under term loan facility		$ 650,000
Subsequent Event [Member] | Senior Notes [Member]
Subsequent Event [Line Items]
Senior notes, aggregate principal amount redeemed			$ 350,000
Senior notes, interest rate			6.125%
Percentage of par value of senior notes			100.00%
Notes payable commencing date			Jan. 15, 2016
Maturity date			Jul. 15, 2023
Description of effective interest rate		Reduced the applicable margins used to calculate interest rates for term loans under our Senior Secured Credit Facilities to 3.25% for LIBOR rate loans and 2.25% for base rate loans, subject to a LIBOR floor of 1.00% (and one 25 basis point step down upon Summit LLC achieving a certain first lien net leverage ratio)
Percentage of senior notes		3.25%
LIBOR floor interest rate		1.00%
Percentage reduction in basis points achieving first lien net leverage ratio		0.25%
Subsequent Event [Member] | Senior Notes [Member] | Summit Materials, LLC [Member]
Subsequent Event [Line Items]
Senior notes, aggregate principal amount redeemed			$ 350,000
Senior notes, interest rate			6.125%
Percentage of par value of senior notes			100.00%
Notes payable commencing date			Jan. 15, 2016
Maturity date			Jul. 15, 2023
Description of effective interest rate		Reduced the applicable margins used to calculate interest rates for term loans under our Senior Secured Credit Facilities to 3.25% for LIBOR rate loans and 2.25% for base rate loans, subject to a LIBOR floor of 1.00% (and one 25 basis point step down upon Summit LLC achieving a certain first lien net leverage ratio)
Percentage of senior notes		3.25%
LIBOR floor interest rate		1.00%
Percentage reduction in basis points achieving first lien net leverage ratio		0.25%
Davenport Acquisition [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Aggregate cash consideration to be paid		$ 450,000
Davenport Acquisition [Member] | Subsequent Event [Member] | Summit Materials, LLC [Member]
Subsequent Event [Line Items]
Aggregate cash consideration to be paid		$ 450,000
Base Rate [Member] | Subsequent Event [Member] | Senior Notes [Member]
Subsequent Event [Line Items]
Basis spread on variable rate		2.25%
Base Rate [Member] | Subsequent Event [Member] | Senior Notes [Member] | Summit Materials, LLC [Member]
Subsequent Event [Line Items]
Basis spread on variable rate		2.25%
Common Class A [Member]
Subsequent Event [Line Items]
Common stock shares issued				26,584,738
Common Class A [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Common stock shares issued	19,500,000
Issue price per share	$ 25.75
Number of days granted for underwriters to purchase additional units	30 days
Number of additional shares to underwriters	2,925,000
Common Class A [Member] | Subsequent Event [Member] | Summit Materials, LLC [Member]
Subsequent Event [Line Items]
Common stock shares issued	19,500,000
Issue price per share	$ 25.75
Number of days granted for underwriters to purchase additional units	30 days
Number of additional shares to underwriters	2,925,000

Accumulated Other Comprehensi57

Accumulated Other Comprehensive Loss - Summary of Changes in Each Component of Accumulated Comprehensive Income Loss (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 27, 2015	Jun. 27, 2015	Jun. 28, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign currency translation adjustment	$ 1,064	$ (5,235)
Postretirement adjustment			$ 2,164
Ending balance	14	14
Summit Materials, LLC [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(15,546)
Foreign currency translation adjustment	1,064	(5,235)
Postretirement adjustment			2,164
Ending balance	(20,781)	(20,781)
Summit Materials, LLC [Member] | Pension And Postretirement Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(9,730)	(6,045)
Ending balance	(9,730)	(9,730)	(5,472)
Summit Materials, LLC [Member] | Pension And Postretirement Plans [Member] | Postretirement Curtailment Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Postretirement adjustment			(942)
Summit Materials, LLC [Member] | Pension And Postretirement Plans [Member] | Postretirement Liability Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Postretirement adjustment			1,515
Summit Materials, LLC [Member] | Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(5,816)
Foreign currency translation adjustment		(5,235)
Ending balance	(11,051)	(11,051)
Summit Materials, LLC [Member] | Accumulated Other Comprehensive Loss (AOCI) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(15,546)	(6,045)
Foreign currency translation adjustment		(5,235)
Ending balance	$ (20,781)	$ (20,781)	(5,472)
Summit Materials, LLC [Member] | Accumulated Other Comprehensive Loss (AOCI) [Member] | Postretirement Curtailment Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Postretirement adjustment			(942)
Summit Materials, LLC [Member] | Accumulated Other Comprehensive Loss (AOCI) [Member] | Postretirement Liability Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Postretirement adjustment			$ 1,515

2020 Notes' Guarantor and Non58

2020 Notes' Guarantor and Non-Guarantor Financial Information - Schedule of Condensed Consolidating Balance Sheets (Detail) - USD ($) $ in Thousands	Jun. 27, 2015	Dec. 27, 2014	Jun. 28, 2014	Dec. 28, 2013
Current assets:
Cash	$ 12,570	$ 13,215	$ 24,069	$ 18,184
Accounts receivable, net	164,059	141,302
Cost and estimated earnings in excess of billings	24,721	10,174
Inventories	128,417	111,553
Other current assets	19,853	17,172
Total current assets	349,620	293,416
Property, plant and equipment, net	985,081	950,601
Goodwill	418,659	419,270
Intangible assets, net	16,257	17,647
Other assets	45,875	48,843
Total assets	1,815,492	1,729,777
Current liabilities:
Current portion of debt	71,275	5,275
Current portion of acquisition-related liabilities	22,395	18,402
Accounts payable	90,822	78,854
Accrued expenses	90,778	101,496
Billings in excess of costs and estimated earnings	8,341	8,958
Total current liabilities	283,611	212,985
Long-term debt	755,972	1,059,642
Acquisition-related liabilities	42,869	42,736
Other noncurrent liabilities	114,153	93,691
Total liabilities	1,196,605	1,409,054
Redeemable noncontrolling interest		33,740		286,817
Total liabilities, redeemable noncontrolling interest and member's interest	1,815,492	1,729,777
Summit Materials, LLC [Member]
Current assets:
Cash	12,570	13,215	20,802	14,917
Accounts receivable, net	164,059	141,302
Cost and estimated earnings in excess of billings	24,721	10,174
Inventories	128,417	111,553
Other current assets	19,853	17,172
Total current assets	349,620	293,416
Property, plant and equipment, net	985,081	950,601
Goodwill	418,659	419,270
Intangible assets, net	16,257	17,647
Other assets	45,875	48,843
Total assets	1,815,492	1,729,777
Current liabilities:
Current portion of debt	71,275	5,275
Current portion of acquisition-related liabilities	19,895	18,402
Accounts payable	90,822	78,854
Accrued expenses	90,778	101,496
Intercompany payables	4,585
Billings in excess of costs and estimated earnings	8,341	8,958
Total current liabilities	285,696	212,985
Long-term debt	755,972	1,059,642
Acquisition-related liabilities	34,502	42,736
Other noncurrent liabilities	114,153	93,691
Total liabilities	1,190,323	1,409,054
Redeemable noncontrolling interest		33,740
Total stockholders' equity/partners' interest	625,169	286,983
Total liabilities, redeemable noncontrolling interest and member's interest	1,815,492	1,729,777
Summit Materials, LLC [Member] | Consolidation, Eliminations [Member]
Current assets:
Cash	(8,119)	(7,112)	(8,294)	(2,540)
Accounts receivable, net	(881)	(1,233)
Intercompany receivables	(442,839)	(415,030)
Other current assets		(1,853)
Total current assets	(451,839)	(425,228)
Other assets	(1,343,002)	(1,256,418)
Total assets	(1,794,841)	(1,681,646)
Current liabilities:
Current portion of debt	(4,465)	(5,263)
Accounts payable	(881)	(1,233)
Accrued expenses	(8,119)	(8,965)
Intercompany payables	(442,839)	(415,030)
Total current liabilities	(456,304)	(430,491)
Long-term debt	(517,598)	(633,917)
Other noncurrent liabilities	(55,107)	(55,107)
Total liabilities	(1,029,009)	(1,119,515)
Redeemable noncontrolling interest		33,740
Redeemable members' interest		(34,543)
Total stockholders' equity/partners' interest	(765,832)	(561,328)
Total liabilities, redeemable noncontrolling interest and member's interest	(1,794,841)	(1,681,646)
Summit Materials, LLC [Member] | Issuers [Member]
Current assets:
Cash	10,225	10,837	21,685	10,375
Accounts receivable, net		1
Intercompany receivables	429,542	376,344
Other current assets	1,206	7,148
Total current assets	440,973	394,330
Property, plant and equipment, net	8,117	7,035
Other assets	1,248,995	1,153,204
Total assets	1,698,085	1,554,569
Current liabilities:
Current portion of debt	71,275	5,275
Current portion of acquisition-related liabilities		166
Accounts payable	4,266	3,655
Accrued expenses	29,416	37,101
Intercompany payables	46,451	162,728
Total current liabilities	151,408	208,925
Long-term debt	755,972	1,059,642
Other noncurrent liabilities	706	796
Total liabilities	908,086	1,269,363
Total stockholders' equity/partners' interest	789,999	285,206
Total liabilities, redeemable noncontrolling interest and member's interest	1,698,085	1,554,569
Summit Materials, LLC [Member] | Wholly Owned Guarantors [Member]
Current assets:
Cash	808	695	2,681	3,442
Accounts receivable, net	153,726	124,380
Intercompany receivables	7,114	30,539
Cost and estimated earnings in excess of billings	24,490	9,819
Inventories	121,882	98,188
Other current assets	17,051	9,638
Total current assets	325,071	273,259
Property, plant and equipment, net	948,314	610,717
Goodwill	366,669	340,969
Intangible assets, net	14,292	14,245
Other assets	138,530	125,462
Total assets	1,792,876	1,364,652
Current liabilities:
Current portion of debt	4,465	3,990
Current portion of acquisition-related liabilities	19,895	18,236
Accounts payable	81,677	65,018
Accrued expenses	67,035	59,477
Intercompany payables	397,217	245,416
Billings in excess of costs and estimated earnings	8,319	8,931
Total current liabilities	578,608	401,068
Long-term debt	517,598	480,599
Acquisition-related liabilities	34,502	42,736
Other noncurrent liabilities	110,974	65,479
Total liabilities	1,241,682	989,882
Total stockholders' equity/partners' interest	551,194	374,770
Total liabilities, redeemable noncontrolling interest and member's interest	1,792,876	1,364,652
Summit Materials, LLC [Member] | Non Wholly Owned Guarantor [Member]
Current assets:
Cash		2	7	9
Accounts receivable, net		6,629
Intercompany receivables		4,095
Inventories		8,696
Other current assets		464
Total current assets		19,886
Property, plant and equipment, net		302,524
Goodwill		23,124
Intangible assets, net		542
Other assets		25,233
Total assets		371,309
Current liabilities:
Current portion of debt		1,273
Accounts payable		6,845
Accrued expenses		10,178
Intercompany payables		4,052
Total current liabilities		22,348
Long-term debt		153,318
Other noncurrent liabilities		24,787
Total liabilities		200,453
Redeemable members' interest		34,543
Total stockholders' equity/partners' interest		136,313
Total liabilities, redeemable noncontrolling interest and member's interest		371,309
Summit Materials, LLC [Member] | Non-Guarantor Subsidiaries [Member]
Current assets:
Cash	9,656	8,793	$ 4,723	$ 3,631
Accounts receivable, net	11,214	11,525
Intercompany receivables	6,183	4,052
Cost and estimated earnings in excess of billings	231	355
Inventories	6,535	4,669
Other current assets	1,596	1,775
Total current assets	35,415	31,169
Property, plant and equipment, net	28,650	30,325
Goodwill	51,990	55,177
Intangible assets, net	1,965	2,860
Other assets	1,352	1,362
Total assets	119,372	120,893
Current liabilities:
Accounts payable	5,760	4,569
Accrued expenses	2,446	3,705
Intercompany payables	3,756	2,834
Billings in excess of costs and estimated earnings	22	27
Total current liabilities	11,984	11,135
Other noncurrent liabilities	57,580	57,736
Total liabilities	69,564	68,871
Total stockholders' equity/partners' interest	49,808	52,022
Total liabilities, redeemable noncontrolling interest and member's interest	$ 119,372	$ 120,893

2020 Notes' Guarantor and Non59

2020 Notes' Guarantor and Non-Guarantor Financial Information - Schedule of Condensed Consolidating Statements of Operations (Detail) - USD ($) $ in Thousands	2 Months Ended	3 Months Ended		4 Months Ended	6 Months Ended
	Mar. 11, 2015	Jun. 27, 2015	Jun. 28, 2014	Jun. 27, 2015	Jun. 27, 2015	Jun. 28, 2014
Condensed Financial Statements, Captions [Line Items]
Revenue		$ 364,943	$ 324,295		$ 558,930	$ 475,386
Cost of revenue (excluding items shown separately below)		249,170	231,762		407,439	360,437
Depreciation, depletion, amortization and accretion		27,386	21,339		53,512	40,695
Operating income (loss)		42,300	33,922		(16,706)	(1,097)
Interest expense		17,395	21,651		41,504	40,470
(Loss) income from continuing operations before taxes		(6,070)	12,968		(90,375)	(40,676)
Income tax benefit (expense)		(5,345)	(864)		(9,813)	(1,460)
(Loss) income from continuing operations		(725)	13,832		(80,562)	(39,216)
Income from discontinued operations		(758)	(369)		(758)	(349)
Net income (loss)	$ (41,415)	33	14,201	$ (36,499)	(79,804)	(38,867)
Net income (loss) attributable to member of Summit Materials, LLC		(205)			(10,356)
Comprehensive income (loss) attributable to Summit Materials, Inc. and Summit Materials, LLC		859			(10,342)
Summit Materials, LLC [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue		364,943	324,295		558,930	475,386
Cost of revenue (excluding items shown separately below)		249,170	231,762		407,439	360,437
General and administrative expenses		46,087	37,272		114,685	75,351
Depreciation, depletion, amortization and accretion		27,386	21,339		53,512	40,695
Operating income (loss)		42,300	33,922		(16,706)	(1,097)
Other (income) expense, net		30,975	(697)		32,165	(891)
Interest expense		17,104	21,651		41,213	40,470
(Loss) income from continuing operations before taxes		(5,779)	12,968		(90,084)	(40,676)
Income tax benefit (expense)		(5,345)	(864)		(9,813)	(1,460)
(Loss) income from continuing operations		(434)	13,832		(80,271)	(39,216)
Income from discontinued operations		(758)	(369)		(758)	(349)
Net income (loss)		324	14,201		(79,513)	(38,867)
Net income (loss) attributable to minority interest		13	1,946		(1,969)	(569)
Net income (loss) attributable to member of Summit Materials, LLC		311	12,255		(77,544)	(38,298)
Comprehensive income (loss) attributable to Summit Materials, Inc. and Summit Materials, LLC		1,375	12,255		(82,779)	(37,725)
Summit Materials, LLC [Member] | Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue		(5,068)	(5,511)		(24,071)	(8,869)
Cost of revenue (excluding items shown separately below)		(5,068)	(5,511)		(24,071)	(8,869)
Other (income) expense, net		50,406	31,027		24,923	(5,750)
Interest expense		(4,147)	(1,966)		(10,772)	(3,526)
(Loss) income from continuing operations before taxes		(46,259)	(29,061)		(14,151)	9,276
(Loss) income from continuing operations		(46,259)	(29,061)		(14,151)	9,276
Net income (loss)		(46,259)	(29,061)		(14,151)	9,276
Net income (loss) attributable to minority interest		13	1,946		(1,969)	(569)
Net income (loss) attributable to member of Summit Materials, LLC		(46,272)	(31,007)		(12,182)	9,845
Comprehensive income (loss) attributable to Summit Materials, Inc. and Summit Materials, LLC		(47,336)	(31,007)		(6,947)	9,600
Summit Materials, LLC [Member] | Issuers [Member]
Condensed Financial Statements, Captions [Line Items]
General and administrative expenses		14,972	10,002		52,753	17,690
Depreciation, depletion, amortization and accretion		567	338		1,058	642
Operating income (loss)		(15,539)	(10,340)		(53,811)	(18,332)
Other (income) expense, net		(22,202)	(29,100)		3,583	7,725
Interest expense		6,352	7,932		20,150	13,668
(Loss) income from continuing operations before taxes		311	10,828		(77,544)	(39,725)
Income tax benefit (expense)			(1,427)			(1,427)
(Loss) income from continuing operations		311	12,255		(77,544)	(38,298)
Net income (loss)		311	12,255		(77,544)	(38,298)
Net income (loss) attributable to member of Summit Materials, LLC		311	12,255		(77,544)	(38,298)
Comprehensive income (loss) attributable to Summit Materials, Inc. and Summit Materials, LLC		1,375	12,255		(82,779)	(38,298)
Summit Materials, LLC [Member] | Wholly Owned Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue		346,309	287,307		525,652	427,717
Cost of revenue (excluding items shown separately below)		240,637	210,693		391,864	328,318
General and administrative expenses		29,446	25,080		58,596	53,521
Depreciation, depletion, amortization and accretion		25,471	17,020		49,623	32,731
Operating income (loss)		50,755	34,514		25,569	13,147
Other (income) expense, net		2,761	(1,360)		3,500	(1,553)
Interest expense		13,990	12,643		30,045	24,415
(Loss) income from continuing operations before taxes		34,004	23,231		(7,976)	(9,715)
Income tax benefit (expense)		(5,625)	563		(10,163)	(33)
(Loss) income from continuing operations		39,629	22,668		2,187	(9,682)
Income from discontinued operations		(758)	(369)		(758)	(349)
Net income (loss)		40,387	23,037		2,945	(9,333)
Net income (loss) attributable to member of Summit Materials, LLC		40,387	23,037		2,945	(9,333)
Comprehensive income (loss) attributable to Summit Materials, Inc. and Summit Materials, LLC		40,387	23,037		2,945	(9,333)
Summit Materials, LLC [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue		23,702	14,942		57,349	21,274
Cost of revenue (excluding items shown separately below)		13,601	9,856		39,646	13,362
General and administrative expenses		1,669	290		3,336	566
Depreciation, depletion, amortization and accretion		1,348	278		2,831	545
Operating income (loss)		7,084	4,518		11,536	6,801
Other (income) expense, net		10	(3)		159	45
Interest expense		909	31		1,790	56
(Loss) income from continuing operations before taxes		6,165	4,490		9,587	6,700
Income tax benefit (expense)		280			350
(Loss) income from continuing operations		5,885	4,490		9,237	6,700
Net income (loss)		5,885	4,490		9,237	6,700
Net income (loss) attributable to member of Summit Materials, LLC		5,885	4,490		9,237	6,700
Comprehensive income (loss) attributable to Summit Materials, Inc. and Summit Materials, LLC		$ 6,949	4,490		$ 4,002	6,700
Summit Materials, LLC [Member] | Non Wholly Owned Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue			27,557			35,264
Cost of revenue (excluding items shown separately below)			16,724			27,626
General and administrative expenses			1,900			3,574
Depreciation, depletion, amortization and accretion			3,703			6,777
Operating income (loss)			5,230			(2,713)
Other (income) expense, net			(1,261)			(1,358)
Interest expense			3,011			5,857
(Loss) income from continuing operations before taxes			3,480			(7,212)
(Loss) income from continuing operations			3,480			(7,212)
Net income (loss)			3,480			(7,212)
Net income (loss) attributable to member of Summit Materials, LLC			3,480			(7,212)
Comprehensive income (loss) attributable to Summit Materials, Inc. and Summit Materials, LLC			$ 3,480			$ (6,394)

2020 Notes' Guarantor and Non60

2020 Notes' Guarantor and Non-Guarantor Financial Information - Schedule of Condensed Consolidating Statements of Cash Flows (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 27, 2015	Jun. 28, 2014
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	$ (80,084)	$ (45,880)
Cash flow from investing activities:
Acquisitions, net of cash acquired	(15,863)	(234,870)
Purchase of property, plant and equipment	(43,379)	(49,260)
Proceeds from the sale of property, plant, and equipment	6,039	5,985
Other	610	757
Net cash (used for) provided by investing activities	(52,593)	(277,388)
Cash flow from financing activities:
Capital issuance costs	(36,398)
Net proceeds from debt issuance	242,000	424,750
Payments on long-term debt	(469,628)	(109,246)
Payments on acquisition-related liabilities	(11,970)	(4,259)
Financing costs	(5,130)	(6,354)
Distributions from partnership	(11,842)
Other		(88)
Net cash provided by (used for) financing activities	132,032	329,153
Net increase (decrease) in cash	(645)	5,885
Cash - beginning of period	13,215	18,184
Cash - end of period	12,570	24,069
Summit Materials, LLC [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	(80,084)	(45,880)
Cash flow from investing activities:
Acquisitions, net of cash acquired	(15,863)	(234,870)
Purchase of property, plant and equipment	(43,379)	(49,260)
Proceeds from the sale of property, plant, and equipment	6,039	5,985
Other	610	757
Net cash (used for) provided by investing activities	(52,593)	(277,388)
Cash flow from financing activities:
Proceeds from investment by member	397,975	24,350
Capital issuance costs	(9,373)
Net proceeds from debt issuance	242,000	424,750
Loans received from and payments made on loans from other Summit Companies	0
Payments on long-term debt	(469,628)	(109,246)
Payments on acquisition-related liabilities	(11,970)	(4,259)
Financing costs	(5,130)	(6,354)
Distributions from partnership	(11,842)
Other		(88)
Net cash provided by (used for) financing activities	132,032	329,153
Net increase (decrease) in cash	(645)	5,885
Cash - beginning of period	13,215	14,917
Cash - end of period	12,570	20,802
Summit Materials, LLC [Member] | Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	(167)	(818)
Cash flow from investing activities:
Other		1,166
Net cash (used for) provided by investing activities		1,166
Cash flow from financing activities:
Proceeds from investment by member		(1,166)
Loans received from and payments made on loans from other Summit Companies	(2,062)	(5,936)
Payments on long-term debt	1,055
Other	167	1,000
Net cash provided by (used for) financing activities	(840)	(6,102)
Net increase (decrease) in cash	(1,007)	(5,754)
Cash - beginning of period	(7,112)	(2,540)
Cash - end of period	(8,119)	(8,294)
Summit Materials, LLC [Member] | Non Wholly Owned Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities		(13,153)
Cash flow from investing activities:
Purchase of property, plant and equipment		(11,829)
Net cash (used for) provided by investing activities		(11,829)
Cash flow from financing activities:
Loans received from and payments made on loans from other Summit Companies		25,234
Payments on long-term debt		(254)
Net cash provided by (used for) financing activities		24,980
Net increase (decrease) in cash		(2)
Cash - beginning of period	2	9
Cash - end of period		7
Summit Materials, LLC [Member] | Wholly and Non Wholly Owned Guarantor [Member]
Cash flow from financing activities:
Net increase (decrease) in cash	111
Cash - beginning of period	697
Cash - end of period	808
Summit Materials, LLC [Member] | Issuers [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	(93,127)	(18,665)
Cash flow from investing activities:
Acquisitions, net of cash acquired		(181,754)
Purchase of property, plant and equipment	(1,904)	(2,428)
Net cash (used for) provided by investing activities	(1,904)	(184,182)
Cash flow from financing activities:
Proceeds from investment by member	397,975	24,350
Capital issuance costs	(9,373)
Net proceeds from debt issuance	242,000	424,750
Loans received from and payments made on loans from other Summit Companies	(169,065)	(123,441)
Payments on long-term debt	(349,980)	(104,060)
Payments on acquisition-related liabilities	(166)	(1,000)
Financing costs	(5,130)	(6,354)
Distributions from partnership	(11,842)
Other		(88)
Net cash provided by (used for) financing activities	94,419	214,157
Net increase (decrease) in cash	(612)	11,310
Cash - beginning of period	10,837	10,375
Cash - end of period	10,225	21,685
Summit Materials, LLC [Member] | Wholly Owned Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	6,775	(13,412)
Cash flow from investing activities:
Acquisitions, net of cash acquired	(15,863)	(53,116)
Purchase of property, plant and equipment	(40,969)	(34,666)
Proceeds from the sale of property, plant, and equipment	5,989	5,912
Other	610	(409)
Net cash (used for) provided by investing activities	(50,233)	(82,279)
Cash flow from financing activities:
Loans received from and payments made on loans from other Summit Companies	176,243	104,121
Payments on long-term debt	(120,703)	(4,932)
Payments on acquisition-related liabilities	(11,804)	(3,259)
Other	(167)	(1,000)
Net cash provided by (used for) financing activities	43,569	94,930
Net increase (decrease) in cash	111	(761)
Cash - beginning of period	695	3,442
Cash - end of period	808	2,681
Summit Materials, LLC [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	6,435	168
Cash flow from investing activities:
Purchase of property, plant and equipment	(506)	(337)
Proceeds from the sale of property, plant, and equipment	50	73
Net cash (used for) provided by investing activities	(456)	(264)
Cash flow from financing activities:
Proceeds from investment by member		1,166
Loans received from and payments made on loans from other Summit Companies	(5,116)	22
Net cash provided by (used for) financing activities	(5,116)	1,188
Net increase (decrease) in cash	863	1,092
Cash - beginning of period	8,793	3,631
Cash - end of period	$ 9,656	$ 4,723