Continental Cement Company, L.L.C. S-4 11 Dec 15 Registration of securities issued in business combination transactions Financial data

Document and Entity Information

Document and Entity Information	9 Months Ended
	Sep. 26, 2015
Document And Entity Information [Abstract]
Document Type	S4
Amendment Flag	false
Document Period End Date	Sep. 26, 2015
Trading Symbol	ck0001571371
Entity Registrant Name	SUMMIT MATERIALS, LLC
Entity Central Index Key	1,571,371
Entity Filer Category	Non-accelerated Filer

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Current assets:
Cash and cash equivalents	$ 5,482	$ 13,215	$ 14,917
Accounts receivable, net	205,939	141,302	99,337
Costs and estimated earnings in excess of billings	34,175	10,174	10,767
Inventories	138,036	111,553	96,432
Other current assets	21,762	17,172	13,181
Total current assets	405,394	293,416	234,634
Property, plant and equipment, net	1,276,227	950,601	831,778
Goodwill	567,836	419,270	127,038
Intangible assets, net	15,481	17,647	15,147
Other assets	51,798	48,843	39,197
Total assets	2,316,736	1,729,777	1,247,794
Current liabilities:
Current portion of debt	68,125	5,275	30,220
Current portion of acquisition-related liabilities	17,691	18,402	10,635
Accounts payable	113,226	78,854	72,104
Accrued expenses	90,880	101,496	57,251
Billings in excess of costs and estimated earnings	11,005	8,958	9,263
Total current liabilities	300,927	212,985	179,473
Long-term debt	1,148,068	1,059,642	658,767
Acquisition-related liabilities	33,320	42,736	23,756
Other noncurrent liabilities	114,575	93,691	77,480
Total liabilities	1,596,890	$ 1,409,054	$ 939,476
Commitments and contingencies
Redeemable noncontrolling interest		$ 33,740	$ 24,767
Member's equity	1,039,763	518,647	486,896
Stockholders' Equity/Partners' Interest:
Accumulated deficit	(293,101)	(217,416)	(198,511)
Accumulated other comprehensive loss	(28,087)	(15,546)	(6,045)
Member's interest	718,575	285,685	282,340
Noncontrolling interest	1,271	1,298	1,211
Total member's interest	719,846	286,983	283,551
Total liabilities, redeemable noncontrolling interest and member's interest	$ 2,316,736	$ 1,729,777	$ 1,247,794

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Revenue:
Product	$ 338,020	$ 258,860	$ 748,210	$ 580,351	$ 838,026	$ 593,570	$ 588,762
Service	88,266	89,276	182,224	196,214	366,205	322,631	337,492
Net revenue	426,286	348,136	930,434	776,565	1,204,231	916,201	926,254
Delivery and subcontract revenue	45,619	46,623	100,401	93,580
Total revenue	471,905	394,759	1,030,835	870,145	1,204,231	916,201	926,254
Cost of revenue (excluding items shown separately below):
Product	207,500	176,967	490,923	411,581	598,732	430,172	444,569
Service	59,280	61,907	128,514	140,773	288,428	246,880	268,777
Net cost of revenue	266,780	238,874	619,437	552,354	887,160	677,052	713,346
Delivery and subcontract cost	45,619	46,623	100,401	93,580
Total cost of revenue	312,399	285,497	719,838	645,934	887,160	677,052	713,346
General and administrative expenses	42,539	35,517	149,484	105,872	150,732	142,000	127,215
Goodwill impairment						68,202
Depreciation, depletion, amortization and accretion	33,306	23,255	86,818	63,950	87,826	72,934	68,290
Transaction costs	304	2,741	8,044	7,737	8,554	3,990	1,988
Operating (loss) income	83,357	47,749	66,651	46,652	69,959	(47,977)	15,415
Other income, net	(1,171)	(1,408)	(678)	(2,299)	(3,447)	(1,737)	(1,182)
Loss on debt financings	32,641		64,313			3,115	9,469
Interest expense	20,436	22,085	61,649	62,555	86,742	56,443	58,079
(Loss) income from continuing operations before taxes	31,451	27,072	(58,633)	(13,604)	(13,336)	(105,798)	(50,951)
Income tax benefit	(2,655)	(1,038)	(12,468)	(2,498)	(6,983)	(2,647)	(3,920)
Income (loss) from continuing operations	34,106	28,110	(46,165)	(11,106)	(6,353)	(103,151)	(47,031)
Income (loss) from discontinued operations	(57)	(7)	(815)	(356)	(71)	528	3,546
Net income (loss)	34,163	28,117	(45,350)	(10,750)	(6,282)	(103,679)	(50,577)
Net income (loss) attributable to noncontrolling interest	52	1,243	(1,917)	674	2,495	3,112	1,919
Net income (loss) attributable to member of Summit Materials, LLC	$ 34,111	$ 26,874	$ (43,433)	$ (11,424)	$ (8,777)	$ (106,791)	$ (52,496)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 34,163	$ 28,117	$ (45,350)	$ (10,750)	$ (6,282)	$ (103,679)	$ (50,577)
Other comprehensive (loss) income:
Postretirement curtailment adjustment				(1,346)	(1,346)
Postretirement liability adjustment				2,164	(3,919)	4,407	(3,648)
Foreign currency translation adjustment	(6,296)	(1,764)	(11,531)	(1,764)	(5,816)
Loss on cash flow hedges	(1,010)		(1,010)
Other comprehensive (loss) income	(7,306)	(1,764)	(12,541)	(946)	(11,081)	4,407	(3,648)
Comprehensive income (loss)	26,857	26,353	(57,891)	(11,696)	(17,363)	(99,272)	(54,225)
Less comprehensive income (loss) attributable to the noncontrolling interest	52	1,243	(1,917)	919	915	4,434	824
Comprehensive income (loss) attributable to member of Summit Materials, LLC	$ 26,805	$ 25,110	$ (55,974)	$ (12,615)	$ (18,278)	$ (103,706)	$ (55,049)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Cash flow from operating activities:
Net loss	$ (45,350)	$ (10,750)	$ (6,282)	$ (103,679)	$ (50,577)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, depletion, amortization and accretion	90,207	68,467	95,211	75,927	72,179
Net interest expense	2,731	2,875	252	3,256	3,266
Share-based compensation expense	18,589	1,746	2,235	2,315	2,533
Deferred income tax benefit		(525)	(5,927)	(4,408)	(3,468)
Net (gain) loss on asset disposals	(4,990)	(219)	6,500	12,419	2,564
Goodwill impairment				68,202
Loss on debt financings	(4,570)			2,989	9,469
Other	136	(463)	(957)	(1,098)	(874)
(Increase) decrease in operating assets, net of acquisitions:
Accounts receivable, net	(56,287)	(54,463)	(10,366)	9,884	5,201
Inventories	(3,830)	(3,843)	(3,735)	499	(1,726)
Costs and estimated earnings in excess of billings	(23,402)	(15,009)	1,359	196	6,931
Other current assets	(4,401)	(3,910)	(3,997)	(453)	3,494
Other assets	(524)	(675)	4,767	(1,708)	1,189
(Decrease) increase in operating liabilities, net of acquisitions:
Accounts payable	29,383	9,433	(6,455)	4,067	(6,076)
Accrued expenses	(12,272)	2,578	13,162	(742)	17,175
Billings in excess of costs and estimated earnings	(763)	270	(305)	1,998	2,589
Other liabilities	(853)	(3,473)	(6,373)	(3,252)	(1,590)
Net cash used in operating activities	(18,927)	(10,836)	79,089	66,412	62,279
Cash flow from investing activities:
Acquisitions, net of cash acquired	(505,466)	(351,941)	(397,854)	(61,601)	(48,757)
Purchases of property, plant and equipment	(69,672)	(64,244)	(76,162)	(65,999)	(45,488)
Proceeds from the sale of property, plant and equipment	8,883	9,575	13,366	16,085	8,836
Other	610	757	(630)		69
Net cash used for investing activities	(565,645)	(405,853)	(461,280)	(111,515)	(85,340)
Cash flow from financing activities:
Capital contributions by partners			27,617
Capital contributions by member	490,916	24,350	27,617
Capital issuance costs	(12,539)
Proceeds from debt issuances	1,415,750	657,217	762,250	234,681	726,442
Payments on debt	(1,251,407)	(258,337)	(389,270)	(188,424)	(697,438)
Payments on acquisition-related liabilities	(15,018)	(5,807)	(10,935)	(9,801)	(7,519)
Debt issuance costs	(10,911)	(8,834)	(9,085)	(3,864)	(13,081)
Distributions from partnership	(39,952)
Other		(88)	(88)	(3)	(702)
Net cash provided by (used for) financing activities	576,839	408,501	380,489	32,589	7,702
Net decrease in cash	(7,733)	(8,188)	(1,702)	(12,514)	(15,359)
Cash - Beginning of period	13,215	14,917	14,917	27,431	42,790
Cash - end of period	$ 5,482	$ 6,729	$ 13,215	$ 14,917	$ 27,431

Consolidated Statements of Chan

Consolidated Statements of Changes in Redeemable Noncontrolling Interest and Stockholders' Equity /Member's Interest - USD ($) $ in Thousands	Total	Member's Equity [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss (AOCI) [Member]	Noncontrolling Interest [Member]	Total Member's Interest [Member]	Redeemable Noncontrolling Interest [Member]
Beginning Balance at Dec. 31, 2011		$ 482,707	$ (40,932)	$ (6,577)	$ 1,174	$ 436,372
Beginning Balance at Dec. 31, 2011							$ 21,300
Accretion/ redemption value adjustment			(657)			(657)	657
Net (loss) income	$ (50,577)		(52,496)		(69)	(52,565)	1,988
Other comprehensive income	(3,648)			(2,553)		(2,553)	(1,095)
Share-based compensation		2,533				2,533
Repurchase of member's interest		(656)				(656)
Payment of dividends					(46)	(46)
Ending Balance at Dec. 29, 2012							22,850
Ending Balance at Dec. 29, 2012		484,584	(94,085)	(9,130)	1,059	382,428
Accretion/ redemption value adjustment			2,365			2,365	(2,365)
Net (loss) income	(103,679)		(106,791)		152	(106,639)	2,960
Other comprehensive income	4,407			3,085		3,085	1,322
Share-based compensation		2,315				2,315
Repurchase of member's interest		(3)				(3)
Ending Balance at Dec. 28, 2013	24,767						24,767
Ending Balance at Dec. 28, 2013	283,551	486,896	(198,511)	(6,045)	1,211	283,551
Contributed capital		24,350				24,350
Accretion/ redemption value adjustment			(6,211)			(6,211)	6,211
Net (loss) income	(10,750)		(11,424)		77	(11,347)	597
Other comprehensive income	(946)			(1,191)		(1,191)	245
Share-based compensation		3,732	(1,982)			1,750
Repurchase of member's interest		(88)				(88)
Ending Balance at Sep. 27, 2014							31,820
Ending Balance at Sep. 27, 2014		514,890	(218,128)	(7,236)	1,288	290,814
Beginning Balance at Dec. 28, 2013	283,551	486,896	(198,511)	(6,045)	1,211	283,551
Beginning Balance at Dec. 28, 2013	24,767						24,767
Contributed capital		27,617				27,617
Accretion/ redemption value adjustment			(8,145)			(8,145)	8,145
Net (loss) income	(6,282)		(8,777)		87	(8,690)	2,408
Other comprehensive income	(11,081)			(9,501)		(9,501)	(1,580)
Share-based compensation		4,222	(1,983)			2,239
Repurchase of member's interest		(88)				(88)
Ending Balance at Dec. 27, 2014	33,740						33,740
Ending Balance at Dec. 27, 2014	286,983	518,647	(217,416)	(15,546)	1,298	286,983
Beginning Balance at Sep. 27, 2014		514,890	(218,128)	(7,236)	1,288	290,814
Beginning Balance at Sep. 27, 2014							31,820
Net (loss) income	4,468
Ending Balance at Dec. 27, 2014	33,740						33,740
Ending Balance at Dec. 27, 2014	286,983	518,647	(217,416)	(15,546)	1,298	286,983
Contributed capital		542,479				542,479
Accretion/ redemption value adjustment			(32,252)			(32,252)	(31,850)
Net (loss) income	(45,350)		(43,433)		(27)	(43,460)	$ (1,890)
Other comprehensive income	(12,541)			(12,541)		(12,541)
Distributions		(39,952)				(39,952)
Share-based compensation		18,589				18,589
Ending Balance at Sep. 26, 2015	$ 719,846	$ 1,039,763	$ (293,101)	$ (28,087)	$ 1,271	$ 719,846

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Statement of Financial Position [Abstract]
Property, plant and equipment, accumulated depreciation, depletion and amortization	$ 343,087	$ 279,375	$ 212,382
Intangible assets, accumulated amortization	$ 4,851	$ 3,073	$ 2,193

Summary of Organization and Sig

Summary of Organization and Significant Accounting Policies	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Accounting Policies [Abstract]
Summary of Organization and Significant Accounting Policies	1. SUMMARY OF ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES Summit Materials, LLC (“Summit LLC” and, together with its subsidiaries, the “Company”) is a vertically integrated, construction materials company. The Company is engaged in the production and sale of aggregates, cement, ready-mixed concrete, asphalt paving mix and concrete products and owns and operates quarries, sand and gravel pits, two cement plants, 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 primary owners are Summit Materials, Inc. (“Summit Inc.”) and certain investment funds affiliated with Blackstone Capital Partners V L.P. and Silverhawk Summit, L.P. (collectively, the “Sponsors”). Summit Inc. was formed as a Delaware corporation on September 23, 2014 to be a holding company. Its sole material asset is a controlling equity interest in Summit Holdings. Pursuant to a reorganization into a holding company structure (the “Reorganization”) in connection with Summit Inc.’s March 2015 initial public offering, Summit Inc. became a holding corporation operating and controlling all of the business and affairs of Summit Holdings and its subsidiaries, including Summit LLC. Initial Public Offering 1 2 Follow-On Offering 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 September 26, 2015, the results of operations for the three and nine months ended September 26, 2015 and September 27, 2014 and cash flows for the nine months ended September 26, 2015 and September 27, 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 LLC and its subsidiaries, including noncontrolling interests. 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— Fair Value Measurements— September 26, 2015 December 27, 2014 Current portion of derivatives and acquisition-related liabilities: Contingent consideration $ 4,559 $ 2,375 Cash flow hedge 114 Derivatives and acquisition- related liabilities: Contingent consideration $ 2,711 $ 5,379 Cash flow hedge 897 The fair value of contingent consideration was 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. The fair value of the derivatives are based on observable, or Level 2, inputs such as interest rates, bond yields and prices in inactive markets. There were no material valuation adjustments in the three or nine months ended September 26, 2015 or September 27, 2014. Financial Instruments September 26, 2015 December 27, 2014 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt (1) $ 1,155,557 $ 1,156,193 $ 1,101,873 $ 1,064,917 Level 3 Current portion of deferred consideration and noncompete obligations (2) 13,132 13,132 16,027 16,027 Long term portion of deferred consideration and noncompete obligations (3) 30,609 30,609 37,357 37,357 (1) $8.1 million and $5.3 million included in current portion of debt as of September 26, 2015 and December 27, 2014, respectively. Excludes $60.0 million outstanding on the revolving credit facility as of September 26, 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	(1) Summary of Organization and Significant Accounting Policies Summit Materials, LLC (“Summit Materials”) is a vertically-integrated, construction materials company. Across its subsidiaries, it is engaged in the manufacturing and sale of aggregates, cement, ready-mixed concrete and asphalt paving mix. It is also engaged in road paving and related construction services. Summit Materials owns and operates quarries, sand and gravel pits, a cement plant, cement distribution terminals, asphalt plants, ready—mixed concrete plants and landfill sites. The operations of Summit Materials are conducted primarily across 17 states and British Columbia, Canada, with the most significant portion of the Company’s revenue generated in Texas, Kansas, Kentucky, Utah and Missouri. Summit Materials 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. (“BCP”). Summit Materials has a number of subsidiaries that have individually made a number of acquisitions through 2014. The Company is organized by geographic region and has three operating segments, which are also its reporting segments: the Central; West; and East regions. Principles of Consolidation Noncontrolling interests represent a 30% redeemable ownership in Continental Cement Company, L.L.C. (“Continental Cement”) and a 20% ownership in Ohio Valley Asphalt, LLC. In 2013, Continental Cement changed its fiscal year from a calendar year to a 52-week year with each quarter composed of 13 weeks ending on a Saturday, consistent with Summit Materials’ fiscal year. Continental Cement’s fiscal year end in 2014 was December 27 compared to December 28 in 2013 and the calendar year ended December 31 in 2012. The effect of this change to the Company’s financial position, results of operations and liquidity was immaterial. Each of the fiscal years presented were composed of 52 weeks. Use of Estimates Business and Credit Concentrations Accounts Receivable The balances billed but not paid by customers, pursuant to retainage provisions included in contracts, will be due upon completion of the contracts. Revenue and Cost Recognition Revenue from construction contracts are included in service revenue and are recognized under the percentage-of-completion accounting method. The percent complete is measured by the cost incurred to date compared to the estimated total cost of each project. This method is used as management considers expended cost to be the best available measure of progress on these contracts, the majority of which are completed within one year, but may occasionally extend beyond one year. Inherent uncertainties in estimating costs make it at least reasonably possible that the estimates used will change within the near term and over the life of the contracts. Contract costs include all direct material and labor costs and those indirect costs related to contract performance and completion. Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are estimable. General and administrative costs are charged to expense as incurred. Changes in job performance, job conditions and estimated profitability, including those arising from contract penalty provisions and final contract settlements, may result in revisions to costs and income. Such revisions are recognized in the period in which they are determined. An amount equal to contract costs incurred that are attributable to claims is included in revenue when realization is probable and the amount can be reliably estimated. Costs and estimated earnings in excess of billings are composed principally of revenue recognized on contracts (on the percentage-of-completion method) for which billings had not been presented to customers because the amount were not billable under the contract terms at the balance sheet date. In accordance with the contract terms, the unbilled receivables at December 27, 2014 will be billed in 2015. Billings in excess of costs and estimated earnings represent billings in excess of revenue recognized. Revenue from the receipt of waste fuels is classified as service revenue and is based on fees charged for the waste disposal, which are recognized when the waste is accepted. Inventories Property, Plant and Equipment, net Landfill airspace is included in property, plant and equipment at cost and is amortized based on utilization of the asset. Management reassesses the landfill airspace capacity with any changes in value recorded in cost of revenue. Capitalized landfill costs include expenditures for the acquisition of land and related airspace, engineering and permitting costs, cell construction costs and direct site improvement costs. Upon disposal of an asset, the cost and related accumulated depreciation are removed from the Company’s accounts and any gain or loss is included in general and administrative expenses. Depreciation on property, plant and equipment, including assets subject to capital leases, is computed on a straight-line basis or based on the economic usage over the estimated useful life of the asset. The estimated useful lives are generally as follows: Buildings and improvements 7—40 years Plant, machinery and equipment 20—40 years Mobile equipment and barges 15—20 years Office equipment 3—6 years Truck and auto fleet 5—10 years Landfill airspace and improvements 5—60 years Other 2—10 years Depletion of mineral reserves is calculated for proven and probable reserves by the units of production method on a site-by-site basis. Leasehold improvements are amortized on a straight-line basis over the lesser of the asset’s useful life or the remaining lease term. The Company reviews the carrying value of property, plant and equipment for impairment whenever events or circumstances indicate that the carrying value of an asset may not be recoverable from the estimated future cash flows expected to result from its use and eventual disposition. Such indicators may include, among others, deterioration in general economic conditions, adverse changes in the markets in which an entity operates, increases in input costs that have a negative effect on earnings and cash flows or a trend of negative or declining cash flows over multiple periods. Property, plant and equipment is tested for impairment at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets. As a result, the property, plant and equipment impairment test is at a significantly lower level than the level at which goodwill is tested for impairment. In markets where the Company does not produce downstream products (e.g., ready-mixed concrete, asphalt paving mix and paving and related services), the lowest level of largely independent identifiable cash flows is at the individual aggregates operation or a group of aggregates operations collectively serving a local market or the cement operations, as a whole. Conversely, in vertically-integrated markets, the cash flows of the downstream and upstream businesses are not largely independently identifiable and the vertically-integrated operations are considered the lowest level of largely independent identifiable cash flows. In addition, assets are assessed for impairment charges when identified for disposition. Projected losses from disposition are recognized in the period in which they become estimable, which may be in advance of the actual disposition. The net loss from asset dispositions recognized in general and administrative expenses in fiscal years 2014, 2013 and 2012 was $6.5 million, $12.4 million and $2.6 million, respectively. No material impairment charges have been recognized on assets held for use in 2014, 2013 or 2012. The losses are commonly a result of the cash flows expected from selling the asset being less than the expected cash flows that could be generated from holding the asset for use. Accrued Mining and Landfill Reclamation Significant changes in inflation rates or the amount or timing of future cost estimates typically result in both (1) a current adjustment to the recorded liability (and corresponding adjustment to the asset) and (2) a change in accretion of the liability and depreciation of the asset to be recorded prospectively over the remaining capacity of the unmined quarry or landfill. Intangible Assets December 27, 2014 December 28, 2013 Gross Accumulated Net Gross Accumulated Net Leases $ 10,357 $ (2,031 ) $ 8,326 $ 10,430 $ (1,604 ) $ 8,826 Reserve rights 9,094 (540 ) 8,554 5,890 (221 ) 5,669 Trade names 1,020 (470 ) 550 1,020 (368 ) 652 Other 249 (32 ) 217 — — — Total intangible assets $ 20,720 $ (3,073 ) $ 17,647 $ 17,340 $ (2,193 ) $ 15,147 Amortization expense in 2014, 2013 and 2012 was $0.9 million, $0.8 million and $0.6 million, respectively. The estimated amortization expense for intangible assets for each of the next five years and thereafter is as follows: 2015 $ 3,105 2016 1,675 2017 956 2018 956 2019 956 Thereafter 9,999 Total $ 17,647 Goodwill Income Taxes The Company evaluates the tax positions taken on income tax returns that remain open to examination by the respective tax authorities from prior years and positions expected to be taken on the current year tax returns to identify uncertain tax positions. Interest and penalties are recorded in income tax expense. Fair Value Measurements Level 1 — Unadjusted quoted prices for identical assets or liabilities in active markets. Level 2 — Inputs other than Level 1 that are based on observable market data, either directly or indirectly. These include quoted prices for similar assets or liabilities in active markets, quoted prices for identical assets or liabilities in inactive markets, inputs that are observable that are not prices and inputs that are derived from or corroborated by observable markets. Level 3 — Valuations developed from unobservable data, reflecting the Company’s own assumptions, which market participants would use in pricing the asset or liability. Assets and liabilities measured at fair value in the consolidated balance sheets as of December 27, 2014 and December 28, 2013 are as follows: 2014 2013 Accrued expenses: Current portion of contingent consideration $ 2,375 $ — Acquisition- related liabilities Contingent consideration $ 5,379 $ 1,908 Certain acquisitions made by the Company require the payment of additional consideration contingent upon the achievement of specified operating results, referred to as contingent consideration or earn-out obligations. These payments will not be made if earn-out thresholds are not achieved. Approximately $4.5 million and $1.9 million of the increase in contingent consideration obligations relate to the January 17, 2014 acquisition of Alleyton Resource Corporation, Colorado Gulf, LP and certain assets of Barten Shepard Investments, LP (collectively, “Alleyton”) and the October 3, 2014 acquisition of Concrete Supply of Topeka, Inc. and all of the membership interests of Penny’s Concrete and Ready Mix, L.L.C. and Builders Choice Concrete Company of Missouri, L.L.C. (collectively, “Concrete Supply”), respectively. No material earn-out payments have been made to date. Summit Materials records contingent consideration at fair value on the acquisition date and then measures its fair value each reporting period. Any adjustments to fair value are recognized in earnings in the period identified. Management of the Company determines the appropriate policies and procedures to be used when determining the fair value of contingent consideration. Its fair values are based on unobservable inputs, or Level 3 assumptions, including projected probability-weighted cash payments and an 11.0% discount rate, which reflects the Company’s credit risk. 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 significantly lower, or higher, fair value measurement. In 2014 and 2012, we recognized immaterial reductions to contingent consideration of $0.5 million and $0.4 million, respectively. Financial Instruments The fair value of long-term debt was approximately $1,101.9 million and $696.5 million as of December 27, 2014 and December 28, 2013, respectively, compared to its carrying value of $1,064.9 million and $663.0 million, respectively. Fair value was determined based on Level 2 inputs of the fair value hierarchy, including observable inputs, specifically quoted prices for these instruments in inactive markets. The fair value of Company’s revolving credit facility approximated its carrying value of $26.0 million at December 28, 2013. There were no outstanding borrowings on the revolving credit facility as of December 27, 2014.

Acquisitions

Acquisitions	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Business Combinations [Abstract]
Acquisitions	3. ACQUISITIONS On July 17, 2015, the Company acquired the Davenport Assets for a purchase price of $450.0 million in cash and a cement distribution terminal in Bettendorf, Iowa. The operating results of the acquired business have been included in the Central region’s results of operations since the date of the acquisition. Assets acquired and liabilities assumed are measured at their acquisition-date fair value. Goodwill recognized in connection with the acquisition is primarily attributable to the expected profitability, assembled workforces and operational infrastructure of the acquired business and the synergies expected to result after its integration. The Davenport Assets were immediately integrated into the Company’s existing cement operations such that it is not practicable to report revenue and net income separately for the Davenport Assets. Pro Forma Financial Information (unaudited) Three months ended Nine months ended September 26, 2015 September 26, 2015 Revenue $ 477,706 $ 1,069,305 Net income 67,229 24,506 The purchase price allocation for the Davenport Assets has not been finalized due to the recent timing of the acquisition. The following table summarizes aggregated information regarding the estimated fair values of the assets acquired and liabilities assumed in conjunction with the acquisition: September 26, 2015 Inventories $ 21,538 Property, plant and equipment 272,815 Other assets 6,537 Financial liabilities (1,509 ) Other long-term liabilities (95 ) Net assets acquired 299,286 Goodwill 150,710 Total consideration 449,996 Transfer of assets (2,182 ) Working capital true-up 896 Net cash paid for acquisitions $ 448,710	(2) Acquisitions The Company has acquired a number of entities since its formation in 2009, which were financed through a combination of debt and contributions from its member. The operations of each acquisition have been included in the Company’s consolidated results of operations since the respective dates of the acquisitions. The Company measures all assets acquired and liabilities assumed at their acquisition-date fair value. 2014 Acquisitions West region • On September 30, 2014, the Company acquired all of the outstanding ownership interests in Colorado County Sand & Gravel Co., L.L.C., a Texas limited liability company, M & M Gravel Sales, Inc., a Texas corporation, Marek Materials Co. Operating, Ltd., a Texas limited partnership, and Marek Materials Co., L.L.C., a Texas limited liability company (collectively “Colorado County S&G”). Colorado County S&G provides aggregates to the West Houston, Texas market. The acquisition was funded with borrowings under the Company’s revolving credit facility. • On September 19, 2014, the Company acquired all of the membership interests of Southwest Ready-Mix LLC (“Southwest Ready Mix”), which included two ready-mixed concrete plants and serves the downtown and southwest Houston, Texas markets. The acquisition was funded with borrowings under the Company’s revolving credit facility. • On September 4, 2014, the Company acquired all of the issued and outstanding shares and certain shareholder notes of Rock Head Holdings Ltd. and B.I.M. Holdings Ltd., which collectively indirectly owned all of Mainland Sand and Gravel Ltd.’s shares. The surviving entity, Mainland Sand & Gravel ULC. (“Mainland”), based in Surrey, British Columbia, is a supplier of aggregates to the Vancouver metropolitan area. The acquisition was funded with a portion of the proceeds from the September 8, 2014 issue and sale of $115.0 million aggregate principal amount of 10 1 2 • On July 29, 2014, the Company acquired all of the assets of Canyon Redi-Mix, Inc. and CRM Mixers LP (collectively “Canyon Redi-Mix”). The acquired assets include two ready-mixed concrete plants, which serve the Permian Basin region of West Texas. The acquisition was funded with borrowings under the Company’s revolving credit facility. • On March 31, 2014, the Company acquired all of the stock of Troy Vines, Inc., an integrated aggregates and ready-mixed concrete business headquartered in Midland, Texas, which serves the Permian Basin region of West Texas. The acquisition was funded with cash on hand. • On January 17, 2014, the Company acquired all of the membership interests of Alleyton, an aggregates and ready-mixed concrete business in Houston, Texas. The Alleyton acquisition was funded with a portion of the proceeds from the January 17, 2014 issue and sale of $260.0 million aggregate principal amount of 10 1 2 Central region • On October 3, 2014, the Company acquired the stock of Concrete Supply, an aggregates and ready-mixed concrete business with operations in Kansas and Missouri. The acquisition was funded with borrowings under the Company’s revolving credit facility. East region • On June 9, 2014, the Company acquired all of the membership interests of Buckhorn Materials LLC, an aggregates quarry in South Carolina, and Construction Materials Group LLC, a sand pit in South Carolina. The acquisition was funded with borrowings under the Company’s revolving credit facility. 2013 Acquisitions West region • On April 1, 2013, the Company acquired all of the membership interests of Westroc, LLC, an aggregates and ready-mixed concrete provider near Salt Lake City, Utah, with borrowings under the Company’s revolving credit facility. Central region • On April 1, 2013, the Company acquired certain aggregates, ready-mixed concrete and asphalt assets of Lafarge North America, Inc. in and around Wichita, Kansas, with borrowings under the Company’s revolving credit facility. 2012 Acquisitions West region • On November 30, 2012, the Company acquired all of the stock of Sandco, Inc., an aggregates and ready-mixed concrete business in Colorado, with cash on-hand. Central region • On February 29, 2012, the Company acquired certain assets of Norris Quarries, LLC, an aggregates business in northwest Missouri, with proceeds from debt, including the Company’s revolving credit facility. East region • On October 5, 2012, the Company acquired certain assets of Kay & Kay Contracting, LLC, an aggregates, asphalt and paving business in Kentucky, with cash on-hand. Revenue and net income from these acquisitions in the year ended December 27, 2014 was $197.5 million and $35.6 million, respectively, of which $150.9 million and $32.6 million, respectively, was attributable to Alleyton, Southwest Ready Mix and Colorado County S&G. Southwest Ready Mix and Colorado County S&G were integrated with Alleyton as of their respective acquisition dates such that disaggregated financial data is not available. The 2013 and 2012 acquisitions were integrated with existing operations on the respective acquisition dates such that disaggregated financial data is not available. Pro Forma Financial Information (unaudited) Year ended December 27, 2014 December 28, 2013 December 29, 2012 Revenue $ 1,326,861 $ 1,230,491 $ 1,022,535 Net income (loss) 8,181 (104,705 ) (46,405 ) The purchase price allocation for the Canyon Redi-Mix, Mainland, Southwest Ready Mix, Colorado County S&G and Concrete Supply acquisitions has not yet been finalized due to the recent timing of the acquisitions. The following table summarizes aggregated information regarding the fair values of the assets acquired and liabilities assumed as of the respective acquisition dates in 2014, 2013 and 2012: Alleyton Year Ended Year Ended Year Ended Financial assets $ 15,489 $ 22,101 $ 8,302 $ 1,397 Inventories 2,548 8,249 3,954 6,988 Property, plant and equipment 47,985 74,687 40,580 21,543 Intangible assets(1) — 3,398 7,428 3,172 Other assets 2,595 3,337 52 1,330 Financial liabilities (10,054 ) (17,610 ) (6,164 ) (944 ) Other long-term liabilities (990 ) (11,727 ) (1,050 ) (364 ) Net assets acquired 57,573 82,435 53,102 33,122 Goodwill 147,064 148,838 16,120 26,230 Purchase price 204,637 231,273 69,222 59,352 Acquisition related liabilities (22,123 ) (10,656 ) (7,902 ) (10,547 ) Other (2,087 ) (3,190 ) 281 (48 ) Net cash paid for acquisitions $ 180,427 $ 217,427 $ 61,601 $ 48,757 (1) Intangible assets acquired in 2013 related to aggregate reserves to which the Company has the rights of ownership, but does not own the reserves ($5.9 million) and the differential between contractual lease rates and market rates for leases of aggregate reserves and office space. The acquired intangible assets in total, the reserve rights and the lease assets have weighted-average lives of 18 years, 20 years and 11 years, respectively.

Goodwill

Goodwill	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	4. GOODWILL Changes in the carrying amount of goodwill, by reportable segment, from December 27, 2014 to September 26, 2015 are summarized as follows: West Central East Total Balance, December 27, 2014 $ 297,085 $ 96,025 $ 26,160 $ 419,270 Acquisitions (1) 4,579 150,929 — 155,508 Foreign currency translation adjustments (6,942 ) — — (6,942 ) Balance, September 26, 2015 $ 294,722 $ 246,954 $ 26,160 $ 567,836 (1) Includes certain working capital adjustments related to 2014 acquisitions	(3) Goodwill As of December 29, 2014, the Company had 11 reporting units with goodwill for which the annual goodwill impairment test was completed. To perform the annual impairment test on the first day of the fourth quarter of 2014, the Company first assessed qualitative factors to determine whether the existence of events or circumstances led to a determination that it was more likely than not (more than 50%) that the estimated fair value of its reporting units, excluding the Utah-based reporting unit, were less than the carrying amounts. As a result of the qualitative assessment, it was determined that an impairment was not more likely than not. Accordingly, for those reporting units, the two-step quantitative impairment test was not performed. The Utah-based reporting unit has negative equity and, therefore, the Company performed step 2 of the two-step impairment test. The second step of the test requires the allocation of the reporting unit’s fair value to its assets and liabilities, including any unrecognized intangible assets, in a hypothetical analysis that calculates the implied fair value of goodwill as if the reporting unit were being acquired in a business combination. If the implied fair value of goodwill is less than the carrying value, the difference is recorded as an impairment loss. The Company estimated the fair value of the Utah-based reporting unit’s assets and liabilities using either an income approach (a discounted cash flow technique) or a market approach, based on the nature of the asset and liability and the information available. These valuation methods used Level 2 and Level 3 assumptions, including, but not limited to, sales prices of similar assets, assumptions related to future profitability, cash flows, and discount rates. These estimates are based upon historical trends, management’s knowledge and experience and overall economic factors, including projections of future earnings potential. Developing discounted future cash flow estimates in applying the income approach required management to evaluate its intermediate to longer-term strategies, including, but not limited to, estimates about revenue growth, acquisition strategies, operating margins, capital requirements, inflation and working capital management. The development of appropriate rates to discount the estimated future cash flows required the selection of risk premiums, which can materially affect the present value of estimated future cash flows. Based on this analysis, it was determined that the Utah reporting unit’s fair value was greater than its carrying value and no impairment charges were recognized in 2014. During the annual test performed as of the first day of the fourth quarter of 2013, management concluded that the estimated fair value of the Utah-based operations in the West region and of the East region were less than their respective carrying values. The estimated fair value of these operating units was estimated by applying a 50 percent weighting to both the discounted cash flow valuation and the market assessment, a discount rate of 11.0% and internal growth projections. Based on the step two analysis, the Company recognized goodwill impairment charges of $68.2 million in the year ended December 28, 2013, as a result of uncertainties in the timing of a sustained recovery in the construction industry. After recognition of the goodwill impairment charges, the fair values of these reporting units’ goodwill recognized as of December 28, 2013 were: 2013 Goodwill: Utah operations in the West region $ 36,589 East region — No impairment charges were recognized prior to 2013. The following table presents goodwill by reportable segments and in total: West Central East Total Balance, December 29, 2012 $ 91,393 $ 72,789 $ 14,938 $ 179,120 Acquisitions 16,120 — — 16,120 Impairment (53,264 ) — (14,938 ) (68,202 ) Balance, December 28, 2013 54,249 72,789 — 127,038 Acquisitions 246,506 23,236 26,160 295,902 Foreign currency translation adjustments (3,670 ) — — (3,670 ) Balance, December 27, 2014 $ 297,085 $ 96,025 $ 26,160 $ 419,270

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 27, 2014
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	(4) Discontinued Operations The Company’s discontinued operations include a railroad construction and repair business (referred to herein as railroad), environmental remediation operations and certain concrete paving operations. The railroad business involved building and repairing railroad sidings. The environmental remediation operations primarily involved the repair of retaining walls along highways in Kentucky and the removal and remediation of underground fuel storage tanks. The railroad and environmental remediation operations were sold in 2012 in separate transactions for aggregate proceeds of $3.1 million. The concrete paving operations were wound down in 2013 and all assets had been sold in 2014. The results of these operations have been removed from the results of continuing operations for all periods presented. Prior to recognition as discontinued operations, all of these businesses were included in the East region’s operations. Debt and interest expense were not allocated to these businesses since there was no debt specifically attributable to the operations. The discontinued businesses are organized within a limited liability company that 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. The railroad, environmental remediation and concrete paving businesses’ revenue and loss before income taxes, including an immaterial gain on sale, in fiscal years 2014, 2013 and 2012 are summarized below: 2014 2013 2012 Total revenue $ 1,260 $ 3,884 $ 50,152 (Income) loss from discontinued operations before income taxes (71 ) 528 3,546

Accounts Receivable, Net

Accounts Receivable, Net	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Receivables [Abstract]
Accounts Receivable, Net	5. ACCOUNTS RECEIVABLE, NET Accounts receivable, net consisted of the following as of September 26, 2015 and December 27, 2014: September 26, December 27, 2015 2014 Trade accounts receivable $ 194,235 $ 131,060 Retention receivables 13,396 12,053 Receivables from related parties 705 333 Accounts receivable 208,336 143,446 Less: Allowance for doubtful accounts (2,397 ) (2,144 ) Accounts receivable, net $ 205,939 $ 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.	(5) Accounts Receivable, Net Accounts receivable, net consisted of the following as of December 27, 2014 and December 28, 2013: 2014 2013 Trade accounts receivable $ 131,060 $ 85,188 Retention receivables 12,053 15,966 Receivables from related parties 333 202 Accounts receivable 143,446 101,356 Less: Allowance for doubtful accounts (2,144 ) (2,019 ) Accounts receivable, net $ 141,302 $ 99,337 Retention receivables are amounts earned by the Company, but held by customers until projects have been fully completed or near completion. Amounts are expected to be billed and collected within a year.

Inventories

Inventories	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Inventory Disclosure [Abstract]
Inventories	6. INVENTORIES Inventories consisted of the following as of September 26, 2015 and December 27, 2014: September 26, December 27, 2015 2014 Aggregate stockpiles $ 90,776 $ 88,211 Finished goods 11,284 8,826 Work in process 6,511 1,801 Raw materials 29,465 12,715 Total $ 138,036 $ 111,553	(6) Inventories Inventories consisted of the following as of December 27, 2014 and December 28, 2013: 2014 2013 Aggregate stockpiles $ 88,211 $ 70,300 Finished goods 8,826 11,207 Work in process 1,801 2,623 Raw materials 12,715 12,302 Total $ 111,553 $ 96,432

Property, Plant and Equipment,

Property, Plant and Equipment, net	12 Months Ended
	Dec. 27, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, net	(7) Property, Plant and Equipment, net Property, plant and equipment, net consisted of the following as of December 27, 2014 and December 28, 2013: 2014 2013 Land (mineral bearing) and asset retirement costs $ 129,957 $ 107,007 Land (non-mineral bearing) 112,932 81,331 Buildings and improvements 86,702 77,535 Plants, machinery and equipment 622,466 553,113 Mobile equipment and barges 182,334 117,828 Office equipment 14,087 10,001 Truck and auto fleet 22,821 19,165 Landfill airspace and improvements 48,513 46,841 Construction in progress 8,445 29,560 Other 1,719 1,779 Property, plant and equipment 1,229,976 1,044,160 Less accumulated depreciation, depletion and amortization (279,375 ) (212,382 ) Property, plant and equipment, net $ 950,601 $ 831,778 Depreciation, depletion and amortization expense of property, plant and equipment was $85.8 million, $71.4 million and $68.6 million for the years ended December 27, 2014, December 28, 2013 and December 29, 2012, respectively. Property, plant and equipment at December 27, 2014 and December 28, 2013 included $30.0 million and $11.3 million, respectively, of capital leases for certain equipment and a building with accumulated amortization of $3.6 million and $1.3 million, respectively. The equipment leases generally have terms of less than five years and the building lease had an original term of 30 years. Approximately $17.5 million of the future obligations associated with the capital leases are included in accrued expenses and the present value of the remaining capital lease payments is included in other noncurrent liabilities on the consolidated balance sheets. Future minimum rental commitments under long-term capital leases are $18.1 million, $5.1 million, $5.3 million, $0.7 million and $0.7 million for the years ended 2015, 2016, 2017, 2018 and 2019, respectively.

Accrued Expenses

Accrued Expenses	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Payables and Accruals [Abstract]
Accrued Expenses	7. ACCRUED EXPENSES Accrued expenses consisted of the following as of September 26, 2015 and December 27, 2014: September 26, December 27, 2015 2014 Interest $ 12,973 $ 32,475 Payroll and benefits 22,095 20,326 Capital lease obligations 16,065 17,530 Insurance 13,710 11,402 Non-income taxes 10,221 5,520 Professional fees 1,305 3,299 Other (1) 14,511 10,944 Total $ 90,880 $ 101,496 (1) Consists primarily of subcontractor and working capital settlement accruals.	(8) Accrued Expenses Accrued expenses consisted of the following as of December 27, 2014 and December 28, 2013: 2014 2013 Interest $ 32,475 $ 17,294 Payroll and benefits 20,326 16,368 Capital lease obligations 17,530 2,068 Insurance 11,402 7,445 Non-income taxes 5,520 4,168 Professional fees 3,299 2,352 Other(1) 10,944 7,556 Total $ 101,496 $ 57,251 (1) Consists primarily of subcontractor and working capital settlement accruals.

Debt

Debt	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Debt Disclosure [Abstract]
Debt	8. DEBT Debt consisted of the following as of September 26, 2015 and December 27, 2014: September 26, December 27, 2015 2014 Revolving credit facility $ 60,000 $ — Long-term debt: 10 1/2% Senior Notes, due 2020: $153.8 million senior notes, including a $5.5 million net premium at September 26, 2015 and $625.0 million senior notes, including a $26.5 million net premium at December 27, 2014 159,365 651,548 6 1/8% Senior Notes, due 2023: $350.0 million senior notes, issued at par at September 26, 2015 350,000 Term Loan, due 2022: $650.0 million term loan, net of $3.1 million discount at September 26, 2015 and $415.7 million term loan, net of $2.3 million discount at December 27, 2014 646,828 413,369 Total 1,156,193 1,064,917 Current portion of long-term debt 8,125 5,275 Long-term debt $ 1,148,068 $ 1,059,642 The contractual payments of long-term debt, including current maturities, for the five years subsequent to September 26, 2015, are as follows: 2015 (three months) $ 3,250 2016 6,500 2017 6,500 2018 4,875 2019 6,500 2020 161,925 Thereafter 964,250 Total 1,153,800 Plus: Original issue net premium 2,393 Total debt $ 1,156,193 Senior Notes The Issuers issued $350.0 million in aggregate principal amount of 6.125% senior notes due July 15, 2023 (the “2023 Notes”) under an indenture dated July 28, 2015 (as amended and supplemented, the “2015 Indenture”). The net proceeds from the 2023 Notes, with proceeds from the refinancing of the term loan described below, were used to pay the $370.0 million initial purchase price for the Davenport Assets and to redeem $183.0 million aggregate principal amount of the 2020 Notes and pay related fees and expenses. The 2015 Indenture contains covenants and events of default generally consistent with the 2012 Indenture. The 2023 Notes were issued at 100% of their par value. Interest on the 2023 Notes is payable semi-annually in arrears on January 15 and July 15 of each year commencing on January 15, 2016. As of September 26, 2015 and December 27, 2014, the Company was in compliance with all covenants under both indentures, as applicable. In April and August 2015, using proceeds from the IPO and the refinancing of the term loan described below, $288.2 million and $183.0 million, respectively, 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 redemptions, net charges of $14.1 million and $45.4 million were recognized in the three and nine months ended September 26, 2015, respectively. The fees included $18.2 million and $56.4 million for the applicable prepayment premium and $2.8 million and $7.5 million for the write-off of deferred financing fees, partially offset by $6.9 million and $18.5 million of net benefit from the write-off of the original issuance net premium in the three and nine months ended September 26, 2015, respectively. Senior Secured Credit Facilities 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 from $422.0 million 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). 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, a charge of $0.4 million of deferred financing was recognized in the nine months ended September 26, 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 September 26, 2015 was 3.6%. There were $60.0 million of outstanding borrowings under the revolving credit facility as of September 26, 2015, leaving remaining borrowing capacity of $150.6 million, which is net of $24.4 million of outstanding letters of credit. The outstanding letters of credit are renewed annually and support required bonding on construction projects and the Company’s insurance liabilities. Summit LLC’s Consolidated First Lien Net Leverage Ratio, as such term is defined in the Senior Secured Credit Facilities, should be no greater than 4.75:1.0 as of each quarter-end. As of September 26, 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, the 2023 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 $17.8 million and $54.6 million in the three and nine months ended September 26, 2015, respectively, and $19.9 million and $56.4 million in the three and nine months ended September 27, 2014, respectively. The following table presents the activity for the deferred financing fees for the nine months ended September 26, 2015 and September 27, 2014: Deferred financing fees Balance — December 27, 2014 $ 17,215 Loan origination fees 10,911 Amortization (2,731 ) Write off of deferred financing fees (12,135 ) Balance — September 26, 2015 $ 13,260 Balance — December 28, 2013 $ 11,485 Loan origination fees 9,281 Amortization (2,875 ) Balance —September 27, 2014 $ 17,891 Other	(9) Debt Debt as of December 27, 2014 and December 28, 2013 is summarized as follows: 2014 2013 Revolving credit facility $ — $ 26,000 Long-term debt: $625.0 million senior notes, including a $26.5 million net premium at December 27, 2014 and $250 million senior notes, net of $4.0 million discount at December 28, 2013 $ 651,548 $ 245,971 $415.7 million term loan, net of $2.3 million discount at December 27, 2014 and $419.9 million, net of $2.9 million discount at December 28, 2013 413,369 417,016 Total 1,064,917 662,987 Current portion of long-term debt 5,275 4,220 Long-term debt $ 1,059,642 $ 658,767 The total contractual payments of long-term debt for the five years subsequent to December 27, 2014 are as follows: 2015 $ 5,275 2016 4,220 2017 4,220 2018 3,165 2019 398,790 Thereafter 625,000 Total 1,040,670 Plus: Original issue net premium 24,247 Total debt $ 1,064,917 Summit Materials and Summit Materials Finance Corp. issued $250.0 million aggregate principal amount of 10 1 2 On January 17, 2014 and September 8, 2014, Summit Materials and Summit Materials Finance Corp. issued an additional $260.0 million and $115.0 million, respectively, aggregate principal amount of Senior Notes (the “Additional Notes”), receiving proceeds of $409.3 million, before payment of fees and expenses and including a $34.3 million premium. The proceeds from the sale of the Additional Notes were used for the purchases of Alleyton and Mainland, to make payments on the revolving facility and for general corporate purposes. The Additional Notes are treated as a single series with the $250.0 million of senior notes (“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 Notes Senior Secured Credit Facilities Under the Senior Secured Credit Facilities, Summit Materials has revolving credit commitments of $150.0 million. The revolving credit facility matures on January 30, 2017 and bears interest per annum equal to, at Summit Materials’ 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 December 27, 2014 was 4.2%. There were no outstanding borrowings under the revolver facility as of December 27, 2014, leaving remaining borrowing capacity of $126.7 million, which is net of $23.3 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. The Company 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 4.75:1.0 from January 1, 2013 through June 30, 2014; 4.50:1.0 from July 1, 2014 through June 30, 2015, and 4.25:1.0 thereafter. 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 December 27, 2014 and December 28, 2013, the Company was in compliance with all covenants. Summit Materials’ wholly-owned domestic subsidiary companies and its non-wholly-owned subsidiary, Continental Cement, subject to certain exclusions and exceptions are named as subsidiary guarantors of the Senior Notes and the Senior Secured Credit Facilities. In addition, Summit Materials has pledged substantially all of its assets as collateral, subject to certain exclusions and exceptions, for the Senior Secured Credit Facilities. As of December 27, 2014 and December 28, 2013, $17.2 million and $11.5 million, respectively, of deferred financing fees were being amortized over the term of the debt using the effective interest method. Other

Member's Interest

Member's Interest	12 Months Ended
	Dec. 27, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Member's Interest	(10) Member’s Interest Summit Materials’ membership interests are held by Summit Holdings. Business affairs of the Company are managed by the Board of Directors (“Board”) of Summit Materials Holdings, GP, Ltd., the general partner of Summit Holdings, which, as of December 27, 2014, was composed of six directors. Directors of the Board are appointed by the unit holders of Summit Holdings, which is the indirect sole member of the Company. The changes in each component of accumulated other comprehensive loss consisted of the following: Change in Foreign currency Accumulated Balance—December 31, 2011 $ (6,577 ) $ (6,577 ) Postretirement liability adjustment (2,553 ) (2,553 ) Balance—December 29, 2012 (9,130 ) — (9,130 ) Postretirement liability adjustment 3,085 3,085 Balance—December 28, 2013 (6,045 ) — (6,045 ) Postretirement curtailment adjustment (942 ) — (942 ) Postretirement liability adjustment (2,743 ) — (2,743 ) Foreign currency translation adjustment — (5,816 ) (5,816 ) Balance—December 27, 2014 $ (9,730 ) $ (5,816 ) $ (15,546 )

Income Taxes

Income Taxes	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Income Tax Disclosure [Abstract]
Income Taxes	10. 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 September 26, 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 during the three or nine months ended September 26, 2015 and September 27, 2014. Tax Distributions –	(11) Income Taxes For the years ended December 27, 2014, December 28, 2013 and December 31, 2012, income taxes consisted of the following: 2014 2013 2012 Provision for income taxes: Current $ (905 ) $ 1,761 $ (452 ) Deferred (6,078 ) (4,408 ) (3,468 ) Income tax benefit $ (6,983 ) $ (2,647 ) $ (3,920 ) The effective tax rate on pre-tax income differs from the U.S. statutory rate due to the following: 2014 2013 2012 Income tax benefit at federal statutory tax rate $ (4,643 ) $ (37,160 ) $ (19,074 ) Less: Income tax benefit at federal statutory tax rate for LLC entities (2,272 ) 32,801 16,167 State and local income taxes (224 ) 130 (90 ) Depletion expense (129 ) (411 ) (377 ) Goodwill impairment — 1,046 — Effective rate change (241 ) — (532 ) Valuation allowance 1,693 729 36 Impact of international operations (73 ) — — Prior year true-up adjustments and amended returns (624 ) — — Other (470 ) 218 (50 ) Income tax benefit $ (6,983 ) $ (2,647 ) $ (3,920 ) The following table summarizes the components of the net deferred income tax liability as December 27, 2014 and December 28, 2013: 2014 2013 Deferred tax (liabilities) assets: Accelerated depreciation $ (40,141 ) $ (33,146 ) Mining reclamation reserve 2,180 1,502 Net operating loss 7,106 2,227 Capital losses on securities — 997 Net intangible assets (1,072 ) (607 ) Inventory purchase accounting adjustments 1,275 1,288 Working capital (e.g., accrued compensation, prepaid assets) (10 ) 1,655 Deferred tax liabilities, net (30,662 ) (26,084 ) Less valuation allowance on loss carryforwards (2,523 ) (1,826 ) Total $ (33,185 ) $ (27,910 ) Deferred tax balances are included in the consolidated balance sheets under the following captions: Other current assets $ 1,167 $ 2,316 Other noncurrent liabilities (34,352 ) (30,226 ) Total $ (33,185 ) $ (27,910 ) In assessing the realizability of deferred tax assets as of December 27, 2014 and December 28, 2013, management considered whether it was more likely than not that some portion or all of 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 (including the effect of available carryback and carryforward periods), projected future taxable income and tax-planning strategies in making this assessment. Management anticipates the deferred income tax asset related to net operating losses will not be fully utilized before their expiration in 2034; therefore, a valuation allowance has been recorded as of December 27, 2014 and December 28, 2013. At December 27, 2014, the Company has net operating loss carryforwards for federal and state income tax purposes of $18.9 million and $0.8 million, respectively, which are available to offset future federal and state taxable income, if any, through 2033. Summit Materials does not have any uncertain tax positions as of December 27, 2014. Tax years from 2011 to 2014 remain open and subject to audit by federal and state tax authorities. No income tax expense or benefit was recognized in other comprehensive loss in 2014, 2013 or 2012.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 27, 2014
Postemployment Benefits [Abstract]
Employee Benefit Plans	(12) Employee Benefit Plans Deferred Compensation Plan Defined Benefit and Other Postretirement Benefits Plans Continental Cement also sponsors unfunded healthcare and life insurance benefits plans for certain eligible retired employees. Effective January 1, 2014, the plan was amended to eliminate all future retiree health and life coverage for employees. The funded status of the pension and other postretirement benefit plans is recognized in the consolidated balance sheets as the difference between the fair value of plan assets and the benefit obligations. For defined benefit pension plans, the benefit obligation is the projected benefit obligation (“PBO”) and for the healthcare and life insurance benefits plans, the benefit obligation is the accumulated postretirement benefit obligation (“APBO”). The PBO represents the actuarial present value of benefits expected to be paid upon retirement based on estimated future compensation levels. However, since the plans’ participants are not subject to future compensation increases, the plans’ PBO equals the APBO. The APBO represents the actuarial present value of postretirement benefits attributed to employee services already rendered. The fair value of plan assets represents the current market value of assets held by an irrevocable trust fund for the sole benefit of participants. The measurement of the benefit obligations are based on the Company’s estimates and actuarial valuations. These valuations reflect the terms of the plan and use participant-specific information, such as compensation, age and years of service, as well as certain assumptions that require significant judgment, including estimates of discount rates, expected return on plan assets, rate of compensation increases, interest-crediting rates and mortality rates. The Company uses its fiscal year-end as the measurement date for its defined benefit pension and other postretirement benefit plans. Obligations and Funded Status 2014 2013 Pension Healthcare Pension Healthcare Change in benefit obligations: Beginning of period $ 25,644 $ 14,155 $ 28,674 $ 15,810 Service cost 75 106 295 236 Interest cost 1,081 493 963 513 Actuarial loss (gain) 3,798 1,992 (2,674 ) (1,048 ) Special termination benefits — — — 39 Change in plan provision — (2,553 ) — — Benefits paid (1,689 ) (837 ) (1,614 ) (1,395 ) End of period 28,909 13,356 25,644 14,155 Change in fair value of plan assets: Beginning of period $ 19,074 $ — $ 17,863 $ — Actual return on plan assets 526 — 1,512 — Employer contributions 961 837 1,313 1,395 Benefits paid (1,689 ) (837 ) (1,614 ) (1,395 ) End of period 18,872 — 19,074 — Funded status of plans $ (10,037 ) $ (13,356 ) $ (6,570 ) $ (14,155 ) Current liabilities $ — $ (1,041 ) $ — $ (1,268 ) Noncurrent liabilities (10,037 ) (12,315 ) (6,570 ) (12,887 ) Liability recognized $ (10,037 ) $ (13,356 ) $ (6,570 ) $ (14,155 ) Amounts recognized in accumulated other comprehensive loss: Net actuarial loss $ 9,365 $ 5,904 $ 4,831 $ 4,139 Prior service cost — (2,380 ) — (1,346 ) Total amount recognized $ 9,365 $ 3,524 $ 4,831 $ 2,793 The amount recognized in accumulated other comprehensive income (“AOCI”) is the actuarial loss and prior service cost, which has not yet been recognized in periodic benefit cost, adjusted for amounts allocated to the redeemable noncontrolling interest. At December 27, 2014, the actuarial loss expected to be amortized from AOCI to periodic benefit cost in 2015 is $0.3 million and $0.1 million for the pension and postretirement obligations. 2014 2013 2012 Pension Healthcare Pension Healthcare Pension Healthcare Amounts recognized in other comprehensive loss (income): Net actuarial gain (loss) $ 4,650 $ 1,992 $ (2,838 ) $ (1,048 ) $ 2,444 $ 1,597 Prior service cost — (2,553 ) — — — — Amortization of prior year service cost — 174 — 180 — 180 Curtailment benefit — 1,346 — — — — Amortization of gain (117 ) (227 ) (387 ) (314 ) (261 ) (312 ) Total amount recognized $ 4,533 $ 732 $ (3,225 ) $ (1,182 ) $ 2,183 $ 1,465 Components of net periodic benefit cost: Service cost $ 75 $ 106 $ 295 $ 236 $ 276 $ 207 Interest cost 1,081 493 963 513 1,055 585 Amortization of loss 117 227 387 314 261 312 Expected return on plan assets (1,378 ) — (1,348 ) — (1,300 ) (180 ) Curtailment benefit — (1,346 ) — — — — Special termination benefits — — — 39 — — Amortization of prior service credit — (174 ) — (180 ) — — Net periodic benefit cost $ (105 ) $ (694 ) $ 297 $ 922 $ 292 $ 924 Assumptions— 2014 2013 Pension benefits Healthcare Pension benefits Healthcare Discount rate 3.50% - 3.65% 3.52% 4.21% - 4.46% 4.33% Expected long-term rate of return on plan assets 7.30% N/A 7.50% N/A Weighted-average assumptions used to determine net periodic benefit cost for years ended December 27, 2014, December 28, 2013 and December 29, 2012: 2014 2013 2012 Pension benefits Healthcare Pension benefits Healthcare Pension benefits Healthcare Discount rate 4.21% - 4.46% 4.33% 3.30% - 3.57% 3.41% 3.89% - 4.07% 4.00% Expected long-term rate of return on plan assets 7.50% N/A 7.50% N/A 7.50% N/A The expected long-term return on plan assets is based upon the Plans’ consideration of historical and forward-looking returns and the Company’s estimation of what a portfolio, with the target allocation described below, will earn over a long-term horizon. The discount rate is derived using the Citigroup Pension Discount Curve. Assumed health care cost trend rates are 8% grading to 6% and 9% grading to 7% as of year-end 2014 and 2013, respectively. Assumed health care cost trend rates have a significant effect on the amounts reported for the Company’s healthcare and life insurance benefits plans. A one percentage-point change in assumed health care cost trend rates would have the following effects as of year-end 2014 and 2013: 2014 2013 Increase Decrease Increase Decrease Total service cost and interest cost components $ 39 $ (34 ) $ 66 $ (55 ) APBO 1,333 (1,136 ) 1,251 (1,073 ) Plan Assets At year-end 2014 and 2013, the Plans’ assets were invested predominantly in fixed-income securities and publicly traded equities, but may invest in other asset classes in the future subject to the parameters of the investment policy. The Plans’ investments in fixed-income assets include U.S. Treasury and U.S. agency securities and corporate bonds. The Plans’ investments in equity assets include U.S. and international securities and equity funds. The Company estimates the fair value of the Plans’ assets using various valuation techniques and, to the extent available, quoted market prices in active markets or observable market inputs. The descriptions and fair value methodologies for the Plans’ assets are as follows: Fixed Income Securities Equity Securities Cash Precious Metals— The fair value of the Plans’ assets by asset class and fair value hierarchy level as of December 27, 2014 and December 28, 2013 are as follows: 2014 Total fair Quoted prices in active Observable Fixed income securities: Intermediate—government $ 1,468 $ — $ 1,468 Intermediate—corporate 3,342 — 3,342 Short-term—government 2,435 — 2,435 Short-term—corporate 3,700 — 3,700 Equity securities: U.S. Large cap value 1,180 1,180 — U.S. Large cap growth 1,173 1,173 — U.S. Mid cap value 590 590 — U.S. Mid cap growth 598 598 — U.S. Small cap value 597 597 — U.S. Small cap growth 611 611 — International 1,098 1,098 — Cash 1,712 1,712 — Precious metals 368 368 — Total $ 18,872 $ 7,927 $ 10,945 2013 Total fair Quoted prices in active Observable Fixed income securities: Intermediate—government $ 1,647 $ — $ 1,647 Intermediate—corporate 3,138 — 3,138 Short-term—government 2,168 — 2,168 Short-term—corporate 4,040 — 4,040 Equity securities: U.S. Large cap value 1,221 1,221 — U.S. Large cap growth 1,536 1,536 — U.S. Mid cap value 600 600 — U.S. Mid cap growth 603 603 — U.S. Small cap value 610 610 — U.S. Small cap growth 599 599 — International 889 889 — Cash 1,665 1,665 — Precious metals 358 358 — Total $ 19,074 $ 8,081 $ 10,993 Cash Flows The estimated benefit payments for each of the next five years and the five-year period thereafter are as follows: Pension Healthcare and Life 2015 $ 1,715 $ 1,041 2016 1,743 1,015 2017 1,740 893 2018 1,773 893 2019 1,777 823 2020 - 2024 8,524 3,912 Total $ 17,272 $ 8,577

Accrued Mining and Landfill Rec

Accrued Mining and Landfill Reclamation	12 Months Ended
	Dec. 27, 2014
Asset Retirement Obligation Disclosure [Abstract]
Accrued Mining and Landfill Reclamation	(13) Accrued Mining and Landfill Reclamation The Company has asset retirement obligations arising from regulatory or contractual requirements to perform certain reclamation activities at the time that certain quarries and landfills are closed, which are primarily included in other noncurrent liabilities on the consolidated balance sheets. The current portion of the liabilities, $1.6 million and $0.5 million as of December 27, 2014 and December 28, 2013, respectively, is included in accrued and other liabilities on the consolidated balance sheets. The liability was initially measured at fair value and subsequently is adjusted for accretion expense, payments and changes in the amount or timing of the estimated cash flows. The corresponding asset retirement costs are capitalized as part of the carrying amount of the related long-lived asset and depreciated over the asset’s remaining useful life. The following table presents the activity for the asset retirement obligations for the years ended December 27, 2014 and December 28, 2013: 2014 2013 Beginning balance $ 15,781 $ 14,844 Acquired obligations 140 286 Change in cost estimate 2,233 721 Settlement of reclamation obligations (1,178 ) (1,201 ) Additional liabilities incurred 463 414 Accretion expense 871 717 Ending balance $ 18,310 $ 15,781

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	11. 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 records 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. The Company had unapproved change orders and claims of $1.2 million in accounts receivable 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) as of September 26, 2015 and December 27, 2014, respectively. Environmental Remediation Other	(14) Commitments and Contingencies Litigation and Claims The Company is obligated under an indemnification agreement entered into with the sellers of Harper Contracting, Inc., Harper Sand and Gravel, Inc., Harper Excavating, Inc., Harper Ready Mix Company, Inc. and Harper Investments, Inc. (collectively, “Harper”) for the sellers’ ownership interests in a joint venture agreement. The Company has the rights to any benefits under the joint venture as well as the assumption of any obligations, but does not own equity interests in the joint venture. The joint venture has incurred significant losses on a highway project in Utah, which have resulted in requests for funding from the joint venture partners and ultimately from the Company. Through year-end 2014, the Company has funded $8.8 million, $4.0 million in 2012 and $4.8 million in 2011. In 2012 and 2011, the Company recognized losses on the indemnification agreement of $8.0 million and $1.9 million, respectively. As of year-end 2014 and 2013, an accrual of $4.3 million was recorded in other noncurrent liabilities as management’s best estimate of future funding obligations. In February 2011, the Company incurred a property loss related to a sunken barge with cement product aboard. In the year-ended December 28, 2013, the Company recognized $0.8 million of charges for lost product aboard the barge and costs to remove the barge from the waterway. As of December 27, 2014 and December 28, 2013, $0.4 million and $0.9 million, respectively, was included in accrued expenses as management’s best estimate of the remaining costs to remove the barge. Environmental Remediation Other The Company is obligated under various firm purchase commitments for certain raw materials and services that are in the ordinary course of business. Management does not expect any significant changes in the market value of these goods and services during the commitment period that would have a material adverse effect on the financial position, results of operations, and cash flows of the Company. The terms of the purchase commitments are generally less than one year.

Related Party Transactions

Related Party Transactions	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Related Party Transactions [Abstract]
Related Party Transactions	14. 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 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 was 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, and is included in general and administrative expenses. The Company incurred management fees 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 nine months ended September 27, 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 nine months ended September 27, 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 $13.8 million; $13.4 million was paid to affiliates of BMP 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 nine months ended September 26, 2015 and September 27, 2014. On July 17, 2015, the Company purchased the Davenport Assets from Lafarge North America Inc. for a purchase price of $450.0 million in cash and a cement distribution terminal in Bettendorf, Iowa. At closing, $370.0 million of the purchase price was paid, and the remaining $80.0 million was paid on August 13, 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”), which would have been used to pay the $80.0 million deferred purchase price if other financing was not attained by December 31, 2015. For the Equity Commitment Financing, the Company paid a $1.8 million commitment fee to BCP in the nine months ended September 26, 2015. Blackstone Advisory Partners L.P., an affiliate of BMP, 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 $4.7 million and $10.9 million during the three and nine months ended September 27, 2014, respectively. Accounts receivable due from the former noncontrolling member were $0.2 million as of December 27, 2014. In the nine months ended September 27, 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 nine months ended September 27, 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.	(15) Related-Party Transactions The Company incurred management fees paid to Blackstone Management Partners L.L.C. (“BMP”) totaling $4.4 million, $2.6 million and $2.1 million in 2014, 2013 and 2012, respectively, under terms of an agreement dated July 30, 2009, between Summit Holdings and BMP. Under the terms of the agreement, BMP is permitted to, and has, assigned a portion of the fees to which it is entitled to receive to Silverhawk Summit, L.P. and to certain members of management. The fees were paid for consultancy services related to acquisition activities and are included in general and administrative expenses. In addition to the management fee, in consideration of BMP undertaking financial and structural analysis, due diligence investigations, corporate strategy and other advice and negotiation assistance necessary to enable Summit Holdings and its subsidiaries to undertake acquisitions, Summit Holdings pays BMP a transaction fee equal to (x) 1.0% of the aggregate enterprise value of any acquired entity or (y) if such transaction is structured as an asset purchase or sale, 1.0% of the consideration paid for or received in respect of the assets acquired or disposed of. In addition, Summit Holdings has agreed to indemnify BMP and its affiliates against liabilities relating to the services contemplated by the transaction and management fee agreement and reimburse BMP and its affiliates for out-of-pocket expenses incurred in connection with providing such services. Under the transaction and management fee agreement, BMP is permitted to, and has, assigned a portion of the fees it is entitled to receive from Summit Holdings to Silverhawk Summit, L.P. and to certain members of management. Transaction fees paid for the year ended December 27, 2014 were $3.9 million and were immaterial in 2013 or 2012 and amounts paid to Silverhawk Summit, L.P. and to other equity holders were immaterial. The Company earned revenue of $0.6 million and $7.9 million and incurred costs of $0.2 million and $0.2 million in connection with several transactions with unconsolidated affiliates for the years ended December 28, 2013 and December 29, 2012, respectively. As of December 28, 2013, accounts receivable from these affiliates was $0.4 million. As of December 27, 2014, the company had no accounts receivable from these affiliates and an immaterial amount of revenue during the year ended December 27, 2014. Cement sales to companies owned by certain noncontrolling members of Continental Cement were approximately $14.3 million, $12.7 million and $12.5 million for the years ended December 27, 2014, December 28, 2013 and December 29, 2012, respectively, and accounts receivable due from these parties were approximately $1.2 million and $0.2 million as of December 27, 2014 and December 28, 2013, respectively. Blackstone Advisory Partners L.P., an affiliate of Blackstone, served as an initial purchaser of $13.0 million and $5.75 million principal amounts of the senior notes issued in January 2014 and September 2014, respectively, and received compensation in connection therewith.

Acquisition-Related Liabilities

Acquisition-Related Liabilities	12 Months Ended
	Dec. 27, 2014
Business Combinations [Abstract]
Acquisition-Related Liabilities	(16) Acquisition-Related Liabilities A number of acquisition-related liabilities have been recorded subject to terms in the relevant purchase agreements, including deferred consideration and noncompete payments. Noncompete payments have been accrued where certain former owners of newly acquired companies have entered into standard noncompete arrangements. Subject to terms and conditions stated in these noncompete agreements, payments are generally made over a five-year period. Deferred consideration is purchase price consideration paid in the future as agreed to in the purchase agreement and is not contingent on future events. Deferred consideration is scheduled to be paid in years ranging from 5 to 20 years in either monthly, quarterly or annual installments. The remaining payments due under these noncompete and deferred consideration agreements are as follows: 2015 $ 16,051 2016 13,240 2017 10,200 2018 9,660 2019 5,435 Thereafter 16,272 Total scheduled payments 70,858 Present value adjustments (17,474 ) Total noncompete obligations and deferred consideration $ 53,384 Accretion on the deferred consideration and noncompete obligations is recorded in interest expense.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	12. SUPPLEMENTAL CASH FLOW INFORMATION Supplemental cash flow information is as follows: Nine months ended September 26, September 27, 2015 2014 Cash payments: Interest $ 75,990 $ 59,179 Income taxes 1,516 1,345 Non cash financing activities: Purchase of noncontrolling interest in Continental Cement $ (64,102 ) $ —	(17) Supplemental Cash Flow Information Supplemental cash flow information for the years ended December 27, 2014, December 28, 2013 and December 29, 2012 was as follows: 2014 2013 2012 Cash payments: Interest $ 64,097 $ 52,001 $ 36,357 Income taxes 1,361 457 799

Leasing Arrangements

Leasing Arrangements	12 Months Ended
	Dec. 27, 2014
Leases [Abstract]
Leasing Arrangements	(18) Leasing Arrangements Rent expense, including short-term rentals, during the years ended December 27, 2014, December 28, 2013 and December 29, 2012 was $5.5 million, $4.0 million and $3.5 million, respectively. The Company has lease agreements associated with quarry facilities under which royalty payments are made. The payments are generally based on tons sold in a particular period; however, certain agreements have minimum annual payments. Royalty expense recorded in cost of revenue during the years ended December 27, 2014, December 28, 2013 and December 29, 2012 was $9.0 million, $4.5 million and $3.9 million, respectively. Minimum contractual commitments under long-term operating leases, which primarily relate to land, plant and equipment, and under royalty agreements as of December 27, 2014, are as follows: Operating Royalty 2015 $ 5,048 $ 3,303 2016 4,061 4,711 2017 3,223 4,973 2018 2,018 4,522 2019 1,469 4,265

Redeemable Noncontrolling Inter

Redeemable Noncontrolling Interest	12 Months Ended
	Dec. 27, 2014
Noncontrolling Interest [Abstract]
Redeemable Noncontrolling Interest	(19) Redeemable Noncontrolling Interest The Company owns 100 Class A Units of Continental Cement, which represent an approximately 70% economic interest and have a preference in liquidation to the Class B Units. Continental Cement issued 100,000,000 Class B Units in May 2010, which remain outstanding and represent an approximately 30% economic interest. Continental Cement’s Class A Units include a cumulative distribution preference which requires, to the extent distributions are authorized by its Board of Directors a priority return of 11% accruing daily and compounding annually on each anniversary of the date of issuance to Class A Unitholders. To the extent the priority return is not made in a given year, the amount of the priority return will increase the liquidation preference of the Class A Units up to an 80% allowable sharing percentage in distributions and liquidation proceeds. Summit Materials indirectly holds all the Class A Units. The Amended and Restated Continental Cement Limited Liability Company Agreement (“LLC Agreement”) provides the Company with a call right that allows it to require Continental Cement to call the Class B Units at a strike price that approximates fair value. The call right is exercisable after May 2016 either in anticipation of an initial public offering of Summit Materials or if an initial public offering of Summit Materials has already occurred. The Class B unitholders also have a put right that allows them to put the Class B Units to Continental Cement at a strike price that approximates fair value. The put right is exercisable prior to May 2016 upon a sale of control of Summit Materials or at any time after May 2016. The LLC Agreement also includes transfer restrictions that prohibit the Class B unitholders from transferring their units to third parties without the consent of the board of directors of Continental Cement. Because the Class B Units can be put to Continental Cement in the future based on the passage of time, which can be accelerated upon the occurrence of a contingent event, their interests are classified in temporary equity. The redemption value is based upon the estimated fair value of Continental Cement, which is valued using Level 3 inputs. The Company has elected to accrete changes in the redemption value of the redeemable interest over the period from the date of issuance to the earliest anticipated redemption date of the instrument, which was May 2016 as of December 27, 2014, using an interest method. The accretion is an adjustment to the consolidated retained earnings and increased in the third quarter of 2014 consistent with the redemption value increase to an estimated $65.1 million. During the third quarter of 2014, the Company performed an indirect valuation of the Class B Units. The valuation was based on unobservable, or Level 3, inputs, including an assumption on the timing of settlement and projected cash flows. A significant change in these inputs could result in a material increase, or decrease, in the redemption value of the Class B Units. Pursuant to the terms of the LLC Agreement, the Class B unitholders have the right to elect to rollover their interests in Continental Cement in connection with an initial public offering of Summit Materials or a parent entity of Summit Materials. In December 2014, Summit Materials entered into a contribution and purchase agreement with the Class B unitholders for a value consistent with the redemption value referenced above. Concurrently with the consummation of an initial public offering of Summit Materials, Inc., the Class B unitholders will contribute 28,571,429 of the Class B Units of Continental Cement in exchange for units of Summit Owner Holdco LLC (“Summit Owner Holdco”) that, as a result of the transactions contemplated by the contribution and purchase agreement will hold a number of shares of Class A common stock of Summit Materials, Inc. that is equal to 1.469496% of the number of outstanding Summit Holdings LP units immediately prior to giving effect to any LP units issued in connection with an initial public offering and the Class B unitholders will deliver the remaining 71,428,571 Class B Units of Continental Cement to Summit Holdings in exchange for a payment to be made by Summit Holdings in the amount of $35.0 million in cash and $15.0 million aggregate principal amount of non-interest bearing notes that will be payable in six aggregate annual installments of $2.5 million, beginning on the first anniversary of the closing of the initial public offering.

Employee Long Term Incentive Pl

Employee Long Term Incentive Plan	12 Months Ended
	Dec. 27, 2014
Contractors [Abstract]
Employee Long Term Incentive Plan	(20) Employee Long Term Incentive Plan Certain employees of the Company hold Class D unit interests in Summit Holdings that provide rights to cash distributions based on a predetermined distribution formula upon the general partner of Summit Holdings declaring a distribution. Certain of the Class D units vest with the passage of time (time-vesting interests) and the remaining vest when certain investment returns are achieved by the investors of Summit Holdings (performance-vesting interests). Of the time-vesting-interests, 20% vest on the first anniversary of the grant date and the remaining 80% vest monthly over a period of four years following the first anniversary date. Units that are not vested in accordance with their terms within eight years from the grant date are automatically forfeited without consideration. If an employee leaves the Company, the Company can (1) purchase the vested Class D units for a lump sum payment provided certain conditions have been met or (2) elect to convert all of the employee’s Class D units into a right to receive future distributions capped at a termination amount. The termination amount is determined as an amount equal to the fair market value of the Class D unit holder’s vested interests minus any amounts already distributed to the Class D unit holders respective of those Class D units plus interest on the difference between such fair market value and amounts already distributed. The fair value of the time-vesting Class D units granted in 2014, 2013 and 2012 totaled $0.6 million, $1.6 million and $1.1 million, respectively. The weighted-average grant-date fair value in 2014, 2013 and 2012 was $1,368, $2,786 and $3,761, respectively. The following table summarizes information for the Class D unit interests: Time-vesting Interests Performance-vesting Number of Weighted Number of Weighted Beginning balance—December 28, 2013 1,819 $ 2,929 4,877 $ 2,928 Granted 410 1,368 533 1,956 Vested (1,070 ) 3,553 — — Cancelled (280 ) 3,938 (48 ) 1,388 Balance—December 27, 2014 879 2,374 5,362 $ 2,845 The estimated fair value at December 27, 2014 of shares vested during 2014 was $1.5 million. As of December 27, 2014 and December 28, 2013, the cumulative amount of units vested totaled 3,321 and 2,531, respectively. The fair value of the Class D units is estimated as of the grant date using Monte Carlo simulations, which requires the input of subjective assumptions, including the expected volatility and the expected term. The following table presents the weighted average assumptions used to estimate the fair value of grants in 2014, 2013 and 2012: 2014 2013 2012 Class D Units Risk-free interest rate 0.50% - 0.68% 0.50% 1.62% Dividend yield None None None Volatility 58% 58% 47% Expected term 3 - 4 years 4 years 6 - 8 years The risk-free rate is based on the yield at the date of grant of a U.S. Treasury security with a maturity period approximating the expected term. As Summit Holdings has not historically and does not plan to issue regular dividends, a dividend yield of zero was used. The volatility assumption is based on reported data of a peer group of publically traded companies for which historical information was available adjusted for the Company’s capital structure. The expected term is based on expectations about future exercises and represents the period of time that the units granted are expected to be outstanding. Compensation expense for time-vesting interests granted is based on the grant date fair value. The Company recognizes compensation costs on a straight-line basis over the service period, which is generally the vesting period of the award. A forfeiture rate assumption is factored into the compensation cost based on historical forfeitures. Compensation expense for performance-vesting interests would be recognized based on the grant date fair value. However, no compensation expense has been recognized for the performance-vesting interests, as management does not believe it is currently probable that certain investment returns, the performance criteria, will be achieved. Share-based compensation expense, which is recognized in general and administrative expenses, totaled $2.2 million, $2.3 million and $2.5 million in the years ended December 27, 2014, December 28, 2013 and December 29, 2012, respectively. As of December 27, 2014, unrecognized compensation cost totaled $3.1 million. The weighted average remaining contractual term over which the unrecognized compensation cost is to be recognized is 1.7 years as of year-end 2014.

Segment Information

Segment Information	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Segment Reporting [Abstract]
Segment Information	13. 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 Nine months ended September 26, September 27, September 26, September 27, 2015 2014 2015 2014 Revenue: West region $ 261,742 $ 211,302 $ 597,484 $ 478,432 Central region 164,084 126,882 338,613 283,541 East region 46,079 56,575 94,738 108,172 Total revenue $ 471,905 $ 394,759 $ 1,030,835 $ 870,145 Three months ended Nine months ended September 26, September 27, September 26, September 27, 2015 2014 2015 2014 Adjusted EBITDA West region $ 59,574 $ 39,105 $ 110,940 $ 71,646 Central region 53,756 30,820 89,984 59,220 East region 13,383 11,868 15,096 10,462 Corporate and other (8,879 ) (9,381 ) (33,577 ) (28,427 ) Total reportable segments and corporate 117,834 72,412 182,443 112,901 Interest expense 20,436 22,085 61,649 62,555 Depreciation, depletion, amortization and accretion 33,306 23,255 86,818 63,950 Initial public offering costs — — 28,296 — Loss on debt financings 32,641 — 64,313 — Income (loss) from continuing operations before taxes $ 31,451 $ 27,072 $ (58,633 ) $ (13,604 ) Nine months ended September 26, September 27, 2015 2014 Cash paid for capital expenditures: West region $ 32,192 $ 25,496 Central region 24,335 28,485 East region 9,401 6,590 Total reportable segments 65,928 60,571 Corporate and other 3,744 3,673 Total capital expenditures $ 69,672 $ 64,244 Three months ended Nine months ended September 26, September 27, September 26, September 27, 2015 2014 2015 2014 Depreciation, depletion, amortization and accretion: West region $ 13,786 $ 9,155 $ 38,508 $ 23,569 Central region 15,778 9,710 37,198 28,061 East region 3,114 3,984 9,426 11,272 Total reportable segments 32,678 22,849 85,132 62,902 Corporate and other 628 406 1,686 1,048 Total depreciation, depletion, amortization and accretion $ 33,306 $ 23,255 $ 86,818 $ 63,950 September 26, December 27, 2015 2014 Total assets: West region $ 866,516 $ 777,981 Central region 1,189,565 704,134 East region 224,720 221,598 Total reportable segments 2,280,801 1,703,713 Corporate and other 35,935 26,064 Total $ 2,316,736 $ 1,729,777 Three months ended Nine months ended September 26, September 27, September 26, September 27, 2015 2014 2015 2014 Revenue by product:* Aggregates $ 86,070 $ 68,636 $ 218,336 $ 160,002 Cement 68,481 34,171 110,477 69,435 Ready-mixed concrete 95,481 75,429 254,878 189,198 Asphalt 113,249 104,862 219,492 203,944 Paving and related services 185,092 191,157 366,321 391,925 Other (76,468 ) (79,496 ) (138,669 ) (144,359 ) Total revenue $ 471,905 $ 394,759 $ 1,030,835 $ 870,145 * 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.	(21) Segment Information The Company has three operating segments: the Central; West; and East regions, which are its reportable segments. These segments are consistent with the Company’s management reporting structure. The operating results of each segment are regularly reviewed and evaluated by the Chief Executive Officer, the Company’s Chief Operating Decision Maker (“CODM”). The CODM primarily evaluates the performance of its segments and allocates resources to them based on a segment profit metric that we call Adjusted EBITDA, which is computed as earnings from continuing operations before interest, taxes, depreciation, depletion, amortization, accretion and goodwill impairment. In addition, certain items such as management fees are excluded from the calculation of segment profit. Each region has several acquired subsidiaries that are engaged in various activities including quarry mining, aggregate production and contracting. 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 the consolidated financial statements. The following tables display selected financial data for the Company’s reportable business segments as of and for the years ended December 27, 2013, December 28, 2013 and December 29, 2012: 2014 2013 2012 Revenue: West region $ 665,716 $ 426,195 $ 484,922 Central region 391,553 329,621 302,113 East region 146,962 160,385 139,219 Total revenue $ 1,204,231 $ 916,201 $ 926,254 2014 2013 2012 Adjusted EBITDA West region $ 96,133 $ 28,607 $ 14,429 Central region 83,912 72,918 65,767 East region 17,955 15,134 10,782 Corporate and other (36,768 ) (24,878 ) (15,560 ) Total reportable segments and corporate 161,232 91,781 75,418 Interest expense 86,742 56,443 58,079 Depreciation, depletion, amortization and accretion 87,826 72,934 68,290 Goodwill impairment — 68,202 — Loss from continuing operations before taxes $ (13,336 ) $ (105,798 ) $ (50,951 ) 2014 2013 2012 Cash paid for capital expenditures: West region $ 31,968 $ 21,856 $ 14,993 Central region 32,114 33,030 20,996 East region 7,547 7,753 8,736 Total reportable segments 71,629 62,639 44,725 Corporate and other 4,533 3,360 763 Total capital expenditures $ 76,162 $ 65,999 $ 45,488 2014 2013 2012 Depreciation, depletion, amortization and accretion: West region $ 33,271 $ 24,167 $ 23,771 Central region 38,793 33,808 30,215 East region 14,294 14,493 14,223 Total reportable segments 86,358 72,468 68,209 Corporate and other 1,468 466 81 Total depreciation, depletion, amortization and accretion $ 87,826 $ 72,934 $ 68,290 2014 2013 2012 Total assets: West region $ 777,981 $ 383,544 $ 428,115 Central region 704,134 657,421 610,003 East region 221,598 192,486 224,603 Total reportable segments 1,703,713 1,233,451 1,262,721 Corporate and other 26,064 14,343 21,758 Total $ 1,729,777 $ 1,247,794 $ 1,284,479 2014 2013 2012 Revenue by product:* Aggregates $ 229,047 $ 159,019 $ 146,991 Cement 89,911 76,211 77,676 Ready-mixed concrete 274,970 112,878 100,941 Asphalt 278,867 219,811 242,458 Paving and related services 528,817 478,280 505,189 Other (197,381 ) (129,998 ) (147,001 ) Total revenue $ 1,204,231 $ 916,201 $ 926,254 * Revenue by product includes intracompany sales transferred at market value. The elimination of intracompany transactions is included in Other.

Guarantor and Non-Guarantor Fin

Guarantor and Non-Guarantor Financial Information	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Guarantor and Non-Guarantor Financial Information	15. GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION Summit LLC’s domestic wholly-owned subsidiary companies other than Finance Corp. are named as guarantors (collectively, the “Guarantors”) of the 2020 Notes and the 2023 Notes (collectively, the “Senior Notes”). Certain other partially-owned subsidiaries and a non-U.S. entity do not guarantee the Senior Notes (collectively, the “Non-Guarantors”). The Guarantors provide a joint and several, full and unconditional guarantee of the Senior Notes. There are no significant restrictions on Summit LLC’s ability to obtain funds from any of the Guarantor Subsidiaries in the form of dividends or loans. Additionally, there are no significant restrictions on a Guarantor Subsidiary’s ability to obtain funds from Summit LLC or its direct or indirect subsidiaries. The following condensed consolidating balance sheets, statements of operations and cash flows are provided for the Issuers, the Wholly-owned Guarantors and the Non-Guarantors. 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 nine months ended September 26, 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 September 26, 2015 Issuers Wholly- Non- Eliminations Consolidated Assets Current assets: Cash and cash equivalents $ 8,989 $ 1,025 $ 8,130 $ (12,662 ) $ 5,482 Accounts receivable, net — 195,120 11,163 (344 ) 205,939 Intercompany receivables 1,322,050 14,869 8,996 (1,345,915 ) — Cost and estimated earnings in excess of billings — 33,447 728 — 34,175 Inventories — 132,734 5,302 — 138,036 Other current assets 1,088 19,319 1,355 — 21,762 Total current assets 1,332,127 396,514 35,674 (1,358,921 ) 405,394 Property, plant and equipment, net 9,433 1,240,126 26,668 — 1,276,227 Goodwill — 519,759 48,077 — 567,836 Intangible assets, net — 14,044 1,437 — 15,481 Other assets 881,923 132,532 1,271 (963,928 ) 51,798 Total assets $ 2,223,483 $ 2,302,975 $ 113,127 $ (2,322,849 ) $ 2,316,736 Liabilities, Redeemable Noncontrolling Interest and Member’s Interest Current liabilities: Current portion of debt $ 68,125 $ — $ — $ — $ 68,125 Current portion of acquisition-related liabilities — 17,691 — — 17,691 Accounts payable 7,436 102,571 3,563 (344 ) 113,226 Accrued expenses 30,998 70,386 2,158 (12,662 ) 90,880 Intercompany payables 67,671 1,274,510 3,734 (1,345,915 ) — Billings in excess of costs and estimated earnings — 10,983 22 — 11,005 Total current liabilities 174,230 1,476,141 9,477 (1,358,921 ) 300,927 Long-term debt 1,148,068 61,377 — (61,377 ) 1,148,068 Acquisition-related liabilities — 33,320 — — 33,320 Other noncurrent liabilities 1,558 110,856 57,268 (55,107 ) 114,575 Total liabilities 1,323,856 1,681,694 66,745 (1,475,405 ) 1,596,890 Redeemable noncontrolling interest — — — — — Redeemable members’ interest — — — — — Total stockholders’ equity/partners’ interest 899,627 621,281 46,382 (847,444 ) 719,846 Total liabilities, redeemable noncontrolling interest and member’s interest $ 2,223,483 $ 2,302,975 $ 113,127 $ (2,322,849 ) $ 2,316,736 Condensed Consolidating Balance Sheets December 27, 2014 Issuers Non- Wholly- Wholly- Non- Elim- inations Consol- idated Assets Current assets: Cash and cash equivalents $ 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 September 26, 2015 Issuers Wholly- Non- Eliminations Consolidated Revenue $ — $ 454,501 $ 21,472 $ (4,068 ) $ 471,905 Cost of revenue (excluding items shown separately below) — 304,204 12,263 (4,068 ) 312,399 General and administrative expenses 8,881 32,362 1,600 — 42,843 Depreciation, depletion, amortization and accretion 628 31,374 1,304 — 33,306 Operating (loss) income (9,509 ) 86,561 6,305 — 83,357 Other (income) expense, net (58,666 ) 3,639 (17 ) 86,514 31,470 Interest expense 15,046 15,286 900 (10,796 ) 20,436 Income from continuing operations before taxes 34,111 67,636 5,422 (75,718 ) 31,451 Income tax benefit (expense) — (2,690 ) 35 — (2,655 ) Income from continuing operations 34,111 70,326 5,387 (75,718 ) 34,106 Income from discontinued operations — (57 ) — — (57 ) Net income 34,111 70,383 5,387 (75,718 ) 34,163 Net income attributable to minority interest — — — 52 52 Net income attributable to member of Summit Materials, LLC $ 34,111 $ 70,383 $ 5,387 $ (75,770 ) $ 34,111 Comprehensive income attributable to member of Summit Materials, LLC $ 26,805 $ 69,373 $ (909 ) $ (68,464 ) $ 26,805 Condensed Consolidating Statements of Operations For the three months ended September 27, 2014 Issuers Non- Wholly- Wholly- Non- Elim- Consol- Revenue $ — $ 34,171 $ 348,785 $ 22,626 $ (10,823 ) $ 394,759 Cost of revenue (excluding items shown separately below) — 25,603 253,284 17,433 (10,823 ) 285,497 General and administrative expenses 8,694 1,651 27,418 495 — 38,258 Depreciation, depletion, amortization and accretion 406 3,708 18,618 523 — 23,255 Operating (loss) income (9,100 ) 3,209 49,465 4,175 — 47,749 Other (income) expense, net (43,887 ) (945 ) (2,679 ) (16 ) 46,119 (1,408 ) Interest expense 7,913 2,931 13,416 233 (2,408 ) 22,085 Income from continuing operations before taxes 26,874 1,223 38,728 3,958 (43,711 ) 27,072 Income tax benefit (expense) — — (1,038 ) — — (1,038 ) Income from continuing operations 26,874 1,223 39,766 3,958 (43,711 ) 28,110 Income from discontinued operations — — (7 ) — — (7 ) Net income 26,874 1,223 39,773 3,958 (43,711 ) 28,117 Net income attributable to minority interest — — — — 1,243 1,243 Net income attributable to member of Summit Materials, LLC $ 26,874 $ 1,223 $ 39,773 $ 3,958 $ (44,954 ) $ 26,874 Comprehensive income attributable to member of Summit Materials, LLC $ 25,110 $ 1,223 $ 39,773 $ 2,194 $ (43,190 ) $ 25,110 Condensed Consolidating Statements of Operations For the nine months ended September 26, 2015 Issuers Wholly- Non- Eliminations Consolidated Revenue $ — $ 980,153 $ 78,821 $ (28,139 ) $ 1,030,835 Cost of revenue (excluding items shown separately below) — 696,068 51,909 (28,139 ) 719,838 General and administrative expenses 61,634 90,959 4,935 — 157,528 Depreciation, depletion, amortization and accretion 1,686 80,997 4,135 — 86,818 Operating (loss) income (63,320 ) 112,129 17,842 — 66,651 Other (income) expense, net (55,083 ) 7,140 142 111,436 63,635 Interest expense 35,196 45,332 2,689 (21,568 ) 61,649 Income from continuing operations before taxes (43,433 ) 59,657 15,011 (89,868 ) (58,633 ) Income tax benefit (expense) — (12,852 ) 384 — (12,468 ) Income from continuing operations (43,433 ) 72,509 14,627 (89,868 ) (46,165 ) Income from discontinued operations — (815 ) — — (815 ) Net income (43,433 ) 73,324 14,627 (89,868 ) (45,350 ) Net income attributable to minority interest — — — (1,917 ) (1,917 ) Net income attributable to member of Summit Materials, LLC $ (43,433 ) $ 73,324 $ 14,627 $ (87,951 ) $ (43,433 ) Comprehensive income attributable to member of Summit Materials, LLC $ (55,974 ) $ 72,314 $ 3,096 $ (75,410 ) $ (55,974 ) Condensed Consolidating Statements of Operations For the nine months ended September 27, 2014 Issuers Non- Wholly- Wholly- Non- Elim- Consol- Revenue $ — $ 69,435 $ 776,502 $ 43,900 $ (19,692 ) $ 870,145 Cost of revenue (excluding items shown separately below) — 53,229 581,602 30,795 (19,692 ) 645,934 General and administrative expenses 26,384 5,225 80,938 1,062 — 113,609 Depreciation, depletion, amortization and accretion 1,047 10,484 51,351 1,068 — 63,950 Operating (loss) income (27,431 ) 497 62,611 10,975 — 46,652 Other expense (income), net (36,161 ) (2,303 ) (4,233 ) 29 40,369 (2,299 ) Interest expense 21,581 8,788 37,831 289 (5,934 ) 62,555 (Loss) income from continuing operations before taxes (12,851 ) (5,988 ) 29,013 10,657 (34,435 ) (13,604 ) Income tax benefit (1,427 ) — (1,071 ) — — (2,498 ) (Loss) income from continuing operations (11,424 ) (5,988 ) 30,084 10,657 (34,435 ) (11,106 ) Income from discontinued operations — — (356 ) — — (356 ) Net (loss) income (11,424 ) (5,988 ) 30,440 10,657 (34,435 ) (10,750 ) Net loss attributable to noncontrolling interest — — — — 674 674 Net (loss) income attributable to member of Summit Materials, LLC $ (11,424 ) $ (5,988 ) $ 30,440 $ 10,657 $ (35,109 ) $ (11,424 ) Comprehensive (loss) income attributable to member of Summit Materials, LLC $ (12,615 ) (5,170 ) $ 30,440 $ 8,893 $ (34,163 ) $ (12,615 ) Condensed Consolidating Statements of Cash Flows For the nine months ended September 26, 2015 Issuers Wholly- Non- Elim- Consol- Net cash (used in) provided by operating activities $ (140,504 ) $ 112,541 $ 9,203 $ (167 ) $ (18,927 ) Cash flow from investing activities: Acquisitions, net of cash acquired — (505,466 ) — — (505,466 ) Purchase of property, plant and equipment (3,743 ) (65,001 ) (928 ) — (69,672 ) Proceeds from the sale of property, plant, and equipment — 8,821 62 — 8,883 Other — 610 — — 610 Net cash used for investing activities (3,743 ) (561,036 ) (866 ) — (565,645 ) Cash flow from financing activities: Proceeds from investment by member 490,916 — — — 490,916 Capital issuance costs (12,539 ) — — — (12,539 ) Net proceeds from debt issuance 1,415,750 — — — 1,415,750 Loans received from and payments made on loans from other Summit Companies (1,031,576 ) 1,047,015 (9,000 ) (6,439 ) — Payments on long-term debt (669,123 ) (583,340 ) — 1,056 (1,251,407 ) Payments on acquisition-related liabilities (166 ) (14,852 ) — — (15,018 ) Financing costs (10,911 ) — — — (10,911 ) Distributions from partnership (39,952 ) — — — (39,952 ) Other — — — — — Net cash provided by (used for) financing activities 142,399 448,823 (9,000 ) (5,383 ) 576,839 Net increase (decrease) in cash (1,848 ) 328 (663 ) (5,550 ) (7,733 ) Cash — Beginning of period 10,837 697 8,793 (7,112 ) 13,215 Cash— End of period $ 8,989 $ 1,025 $ 8,130 $ (12,662 ) $ 5,482 Condensed Consolidating Statements of Cash Flows For the nine months ended September 27, 2014 Issuers Non- Wholly- Wholly- Non- Elim- Consol- Net cash used in operating activities $ (36,504 ) $ (2,408 ) $ 28,727 $ 668 $ (1,319 ) $ (10,836 ) Cash flow from investing activities: Acquisitions, net of cash acquired (181,754 ) — (170,187 ) — — (351,941 ) Purchase of property, plant and equipment (3,674 ) (13,472 ) (46,575 ) (523 ) — (64,244 ) Proceeds from the sale of property, plant, and equipment — — 9,345 230 — 9,575 Other — — (409 ) — 1,166 757 Net cash (used for) provided by investing activities (185,428 ) (13,472 ) (207,826 ) (293 ) 1,166 (405,853 ) Cash flow from financing activities: Proceeds from investment by member 24,350 — — 1,353 (1,353 ) 24,350 Net proceeds from debt issuance 657,217 — — — — 657,217 Loans received from and payments made on loans from other Summit Companies (195,590 ) 16,383 189,243 (2,113 ) (7,923 ) — Payments on long-term debt (251,062 ) (509 ) (6,766 ) — — (258,337 ) Payments on acquisition-related liabilities (1,500 ) — (4,307 ) — — (5,807 ) Financing costs (8,834 ) — — — — (8,834 ) Other (88 ) — (1,500 ) — 1,500 (88 ) Net cash provided by (used for) financing activities 224,493 15,874 176,670 (760 ) (7,776 ) 408,501 Net increase (decrease) in cash 2,561 (6 ) (2,429 ) (385 ) (7,929 ) (8,188 ) Cash — Beginning of period 10,375 9 3,442 3,631 (2,540 ) 14,917 Cash— End of period $ 12,936 $ 3 $ 1,013 $ 3,246 $ (10,469 ) $ 6,729	(22) Senior Notes’ Guarantor and Non-Guarantor Financial Information The Company’s wholly-owned subsidiary companies (“Wholly-owned Guarantors”) and Continental Cement (“Non-wholly-owned Guarantor”), are named as guarantors (collectively, the “Guarantors”) of the Senior Notes. Other non-wholly-owned subsidiaries, including a subsidiary of Continental Cement, and entities domiciled outside of the United States do not guarantee the Senior Notes (collectively, the “Non-Guarantors”). Summit Materials and Finance Corp. (collectively, the “Issuers”) were co-issuers of the Senior Notes. The Guarantors provide a joint and several, full and unconditional guarantee of the Senior Notes. There are no significant restrictions on the Company’s ability to obtain funds from any of the Guarantor Subsidiaries in the form of a dividend or loan. Additionally, there are no significant restrictions on a Guarantor Subsidiary’s ability to obtain funds from the Company or its direct or indirect subsidiaries. The following condensed consolidating balance sheets, statements of operations and cash flows are provided for the Issuers, the Non-wholly-owned Guarantor, the Wholly-owned Guarantors and the Non-Guarantors. Earnings from subsidiaries are included in other income in the condensed consolidated statements of operations below. The financial information may not necessarily be indicative of financial position, results of operations or cash flows had the guarantor or non-guarantor subsidiaries operated as independent entities. Condensed Consolidating Balance Sheets December 27, 2014 Issuers Non- wholly- owned 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 member’s 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 Balance Sheets December 28, 2013 Issuers Non- wholly- owned Wholly- Non- Eliminations Consolidated Assets Current assets: Cash $ 10,375 $ 9 $ 3,442 $ 3,631 $ (2,540 ) $ 14,917 Accounts receivable, net — 4,587 93,102 3,100 (1,452 ) 99,337 Intercompany receivables 38,134 3,433 30,787 — (72,354 ) — Cost and estimated earnings in excess of billings — — 10,539 228 — 10,767 Inventories — 10,402 85,372 658 — 96,432 Other current assets 750 444 11,715 272 — 13,181 Total current assets 49,259 18,875 234,957 7,889 (76,346 ) 234,634 Property, plant and equipment, net 3,969 301,908 518,935 6,966 — 831,778 Goodwill — 23,124 102,942 972 — 127,038 Intangible assets, net — 642 14,505 — — 15,147 Other assets 296,494 17,973 37,535 1,303 (314,108 ) 39,197 Total assets $ 349,722 $ 362,522 $ 908,874 $ 17,130 $ (390,454 ) $ 1,247,794 Liabilities, Redeemable Noncontrolling Interest and Member’s Interest Current liabilities: Current portion of debt $ 26,010 $ 1,018 $ 3,192 $ — $ — $ 30,220 Current portion of acquisition-related liabilities 2,000 — 8,635 — — 10,635 Accounts payable 5,455 9,387 57,142 1,572 (1,452 ) 72,104 Accrued expenses 12,041 9,185 37,342 1,223 (2,540 ) 57,251 Intercompany payables — — 71,556 798 (72,354 ) — Billings in excess of costs and estimated earnings — — 8,837 426 — 9,263 Total current liabilities 45,506 19,590 186,704 4,019 (76,346 ) 179,473 Long-term debt 19,587 154,590 484,590 — — 658,767 Acquisition-related liabilities 85 — 23,671 — — 23,756 Other noncurrent liabilities 959 20,306 56,215 — — 77,480 Total liabilities 66,137 194,486 751,180 4,019 (76,346 ) 939,476 Redeemable noncontrolling interest — — — — 24,767 24,767 Redeemable members’ interest — 23,450 — — (23,450 ) — Total member’s interest 283,585 144,586 157,694 13,111 (315,425 ) 283,551 Total liabilities, redeemable noncontrolling interest and member’s interest $ 349,722 $ 362,522 $ 908,874 $ 17,130 $ (390,454 ) $ 1,247,794 Condensed Consolidating Statements of Operations and Comprehensive Loss Year ended December 27, 2014 Issuers Non- wholly- owned Guarantor Wholly- Non- Eliminations Consolidated Total revenue $ — $ 94,402 $ 1,065,590 $ 72,172 $ (27,933 ) $ 1,204,231 Cost of revenue (excluding items shown separately below) — 67,951 796,078 51,064 (27,933 ) 887,160 General and administrative expenses 30,736 6,763 119,250 2,537 — 159,286 Depreciation, depletion, amortization and accretion 1,468 14,500 70,116 1,742 — 87,826 Operating (loss) income (32,204 ) 5,188 80,146 16,829 — 69,959 Other (income) expense, net (53,827 ) (14,444 ) (6,687 ) (3 ) 71,514 (3,447 ) Interest expense 31,827 11,608 51,248 1,172 (9,113 ) 86,742 (Loss) income from continuing operations before taxes (10,204 ) 8,024 35,585 15,660 (62,401 ) (13,336 ) Income tax benefit (1,427 ) — (5,766 ) 210 — (6,983 ) (Loss) income from continuing operations (8,777 ) 8,024 41,351 15,450 (62,401 ) (6,353 ) Income from discontinued operations — — (71 ) — — (71 ) Net (loss) income (8,777 ) 8,024 41,422 15,450 (62,401 ) (6,282 ) Net loss attributable to noncontrolling interest — — — — 2,495 2,495 Net (loss) income attributable to member of Summit Materials, LLC $ (8,777 ) $ 8,024 $ 41,422 $ 15,450 $ (64,896 ) $ (8,777 ) Comprehensive (loss) income attributable to member of Summit Materials, LLC $ (18,278 ) $ 2,759 $ 41,422 $ 9,634 $ (53,815 ) $ (18,278 ) Condensed Consolidating Statements of Operations and Comprehensive Loss Year ended December 28, 2013 Summit Non- wholly- owned Wholly- Non- Eliminations Consolidated Total revenue $ — $ 80,759 $ 807,921 $ 41,910 $ (14,389 ) $ 916,201 Cost of revenue (excluding items shown separately below) — 55,241 611,799 24,401 (14,389 ) 677,052 General and administrative expenses 7,241 7,673 129,768 1,308 — 145,990 Goodwill impairment — — 68,202 — — 68,202 Depreciation, depletion, amortization and accretion 465 11,378 60,078 1,013 — 72,934 Operating (loss) income (7,706 ) 6,467 (61,926 ) 15,188 — (47,977 ) Other expense (income), net 99,085 (3,737 ) (3,410 ) 274 (90,834 ) 1,378 Interest expense — 10,702 49,591 382 (4,232 ) 56,443 (Loss) income from continuing operations before taxes (106,791 ) (498 ) (108,107 ) 14,532 95,066 (105,798 ) Income tax expense — — (2,647 ) — — (2,647 ) (Loss) income from continuing operations (106,791 ) (498 ) (105,460 ) 14,532 95,066 (103,151 ) Loss from discontinued operations — — 528 — — 528 Net (loss) income (106,791 ) (498 ) (105,988 ) 14,532 95,066 (103,679 ) Net income attributable to noncontrolling interest — — — — 3,112 3,112 Net (loss) income attributable to member of Summit Materials, LLC $ (106,791 ) $ (498 ) $ (105,988 ) $ 14,532 $ 91,954 $ (106,791 ) Comprehensive (loss) income attributable to member of Summit Materials, LLC $ (106,791 ) $ 3,909 $ (105,988 ) $ 14,532 $ 90,632 $ (103,706 ) Condensed Consolidating Statements of Operations and Comprehensive Loss Year ended December 29, 2012 Summit Non- wholly- owned Wholly- Non- Eliminations Consolidated Total revenue $ — $ 81,516 $ 824,796 $ 33,074 $ (13,132 ) $ 926,254 Cost of revenue (excluding items shown separately below) — 58,319 649,577 18,582 (13,132 ) 713,346 General and administrative expenses 8 6,235 121,633 1,327 — 129,203 Depreciation, depletion, amortization and accretion 81 10,093 57,080 1,036 — 68,290 Operating (loss) income (89 ) 6,869 (3,494 ) 12,129 — 15,415 Other expense (income), net 52,400 (2,065 ) 6,630 (101 ) (48,577 ) 8,287 Interest expense — 12,045 47,293 633 (1,892 ) 58,079 (Loss) income from continuing operations before taxes (52,489 ) (3,111 ) (57,417 ) 11,597 50,469 (50,951 ) Income tax expense 5 — (3,925 ) — — (3,920 ) (Loss) income from continuing operations (52,494 ) (3,111 ) (53,492 ) 11,597 50,469 (47,031 ) Loss from discontinued operations — — 3,546 — — 3,546 Net (loss) income (52,494 ) (3,111 ) (57,038 ) 11,597 50,469 (50,577 ) Net income attributable to noncontrolling interest — — — — 1,919 1,919 Net (loss) income attributable to member of Summit Materials, LLC $ (52,494 ) $ (3,111 ) $ (57,038 ) $ 11,597 $ 48,550 $ (52,496 ) Comprehensive (loss) income attributable to member of Summit Materials, LLC $ (52,494 ) $ (6,759 ) $ (57,038 ) $ 11,597 $ 49,645 $ (55,049 ) Condensed Consolidating Statements of Cash Flows For the year ended December 27, 2014 Issuers Non- wholly- owned Wholly- Non- Eliminations Consolidated Net cash (used in) provided by operating activities $ (40,964 ) $ 11,776 $ 102,219 $ 8,058 $ (2,000 ) $ 79,089 Cash flow from investing activities: Acquisitions, net of cash acquired (181,754 ) — (216,100 ) — — (397,854 ) Purchase of property, plant and equipment (4,534 ) (14,941 ) (55,222 ) (1,465 ) — (76,162 ) Proceeds from the sale of property, plant, and equipment — — 13,134 232 — 13,366 Other — (1,387 ) (597 ) — 1,354 (630 ) Net cash used for investing activities (186,288 ) (16,328 ) (258,785 ) (1,233 ) 1,354 (461,280 ) Cash flow from financing activities: Proceeds from investment by member 27,617 — — 1,354 (1,354 ) 27,617 Net proceeds from debt issuance 762,250 — — — — 762,250 Loans received from and payments made on loans from other Summit Companies (170,915 ) 5,338 173,166 (3,017 ) (4,572 ) — Payments on long-term debt (380,065 ) (793 ) (8,412 ) — — (389,270 ) Payments on acquisition-related liabilities (2,000 ) — (8,935 ) — — (10,935 ) Financing costs (9,085 ) — — — — (9,085 ) Other (88 ) — (2,000 ) — 2,000 (88 ) Net cash provided by (used for) financing activities 227,714 4,545 153,819 (1,663 ) (3,926 ) 380,489 Net increase (decrease) in cash 462 (7 ) (2,747 ) 5,162 (4,572 ) (1,702 ) Cash—Beginning of period 10,375 9 3,442 3,631 (2,540 ) 14,917 Cash—End of period $ 10,837 $ 2 $ 695 $ 8,793 $ (7,112 ) $ 13,215 Condensed Consolidating Statements of Cash Flows For the year ended December 28, 2013 Summit Non- wholly- owned Wholly- Non- Eliminations Consolidated Net cash (used for) provided by operating activities $ (232 ) $ 9,003 $ 44,746 $ 12,895 $ — $ 66,412 Cash flow from investing activities: Acquisitions, net of cash acquired — — (61,601 ) — — (61,601 ) Purchase of property, plant and equipment (3,359 ) (24,896 ) (36,629 ) (1,115 ) — (65,999 ) Proceeds from the sale of property, plant, and equipment — 3 16,020 62 — 16,085 Net cash used for investing activities (3,359 ) (24,893 ) (82,210 ) (1,053 ) — (111,515 ) Cash flow from financing activities Net proceeds from debt issuance 234,681 — — — — 234,681 Loans received from and payments made on loans from other Summit Companies (29,121 ) 15,502 19,726 (8,891 ) 2,784 — Payments on long-term debt (188,424 ) — — — — (188,424 ) Payments on acquisition-related liabilities — — (9,801 ) — — (9,801 ) Financing costs (3,864 ) (3,864 ) Other (3 ) — — — — (3 ) Net cash provided by (used for) financing activities 13,269 15,502 9,925 (8,891 ) 2,784 32,589 Net decrease (increase) in cash 9,678 (388 ) (27,539 ) 2,951 2,784 (12,514 ) Cash—Beginning of period 697 397 30,981 680 (5,324 ) 27,431 Cash—End of period $ 10,375 $ 9 $ 3,442 $ 3,631 $ (2,540 ) $ 14,917 Condensed Consolidating Statements of Cash Flows For the year ended December 29, 2012 Summit Non- wholly- owned Wholly- Non- Eliminations Consolidated Net cash provided by operating activities $ 4,845 $ 12,806 $ 36,649 $ 8,217 $ (238 ) $ 62,279 Cash flow from investing activities: Acquisitions, net of cash acquired — — (48,757 ) — — (48,757 ) Purchase of property, plant and equipment (762 ) (12,174 ) (31,818 ) (734 ) — (45,488 ) Proceeds from the sale of property, plant, and equipment — 69 8,577 190 — 8,836 Other — — 69 — — 69 Net cash used for investing activities (762 ) (12,105 ) (71,929 ) (544 ) — (85,340 ) Cash flow from financing activities Net proceeds from debt issuance 726,459 (17 ) — — — 726,442 Loans received from and payments made on loans from other Summit Companies (25,371 ) (295 ) 39,783 (8,793 ) (5,324 ) — Payments on long-term debt (697,438 ) — — — — (697,438 ) Payments on acquisition-related liabilities — — (7,519 ) — — (7,519 ) Financing costs (13,081 ) — — — — (13,081 ) Other (656 ) — — (284 ) 238 (702 ) Net cash (used for) provided by financing activities (10,087 ) (312 ) 32,264 (9,077 ) (5,086 ) 7,702 Net decrease (increase) in cash (6,004 ) 389 (3,016 ) (1,404 ) (5,324 ) (15,359 ) Cash—Beginning of period 6,701 8 33,997 2,084 — 42,790 Cash—End of period $ 697 $ 397 $ 30,981 $ 680 $ (5,324 ) $ 27,431

Supplementary Data (Unaudited)

Supplementary Data (Unaudited)	12 Months Ended
	Dec. 27, 2014
Quarterly Financial Information Disclosure [Abstract]
Supplementary Data (Unaudited)	(23) Supplementary Data (Unaudited) Supplemental financial information (unaudited) by quarter is as follows for the years ended December 27, 2014 and December 28, 2013: 2014 2013 4Q 3Q 2Q 1Q 4Q 3Q 2Q 1Q Revenue $ 334,086 $ 394,759 $ 324,295 $ 151,091 $ 238,267 $ 316,263 $ 254,842 $ 106,829 Operating income (loss) 23,307 47,749 33,922 (35,019 ) (57,742 ) 37,895 13,731 (41,861 ) Income (loss) from continuing operations 4,753 28,110 13,832 (53,048 ) (70,191 ) 22,950 244 (56,154 ) Loss (income) from discontinued operations 285 (7 ) (369 ) 20 271 160 (26 ) 123 Net income (loss) 4,468 28,117 14,201 (53,068 ) $ (70,462 ) $ 22,790 $ 270 $ (56,277 )

Reorganization

Reorganization	9 Months Ended
	Sep. 26, 2015
Text Block [Abstract]
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 Summit Inc.’s Class A common stock, and options were issued to holders of Class D interests to purchase an aggregate of 4,358,842 shares of Summit Inc.’s Class A common stock (“leverage restoration options”). The exercise price of the warrants and leverage restoration options is 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. 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 Company also granted 240,000 options to purchase shares of Summit Inc.’s 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.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 26, 2015
Equity [Abstract]
Accumulated Other Comprehensive Loss	9. ACCUMULATED OTHER COMPREHENSIVE LOSS The changes in each component of accumulated other comprehensive loss consisted of the following: Change in Foreign currency Cash flow hedge Accumulated Balance — December 27, 2014 $ (9,730 ) $ (5,816 ) $ — $ (15,546 ) Foreign currency translation adjustment — (11,531 ) — (11,531 ) Loss on cash flow hedges — — (1,010 ) (1,010 ) Balance — September 26, 2015 $ (9,730 ) $ (17,347 ) $ (1,010 ) $ (28,087 ) Balance — December 28, 2013 $ (6,045 ) $ — $ — $ (6,045 ) Postretirement curtailment adjustment (942 ) — — (942 ) Postretirement liability adjustment 1,515 — — 1,515 Foreign currency translation adjustment — (1,764 ) — (1,764 ) Balance —September 27, 2014 $ (5,472 ) $ (1,764 ) $ — $ (7,236 )

Summary of Organization and S33

Summary of Organization and Significant Accounting Policies (Policies)	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Accounting Policies [Abstract]
Principles of Consolidation		Principles of Consolidation
Use of Estimates	Use of Estimates	Use of Estimates
Business and Credit Concentrations	Business and Credit Concentrations—	Business and Credit Concentrations
Accounts Receivable		Accounts Receivable The balances billed but not paid by customers, pursuant to retainage provisions included in contracts, will be due upon completion of the contracts.
Revenue and Cost Recognition		Revenue and Cost Recognition Revenue from construction contracts are included in service revenue and are recognized under the percentage-of-completion accounting method. The percent complete is measured by the cost incurred to date compared to the estimated total cost of each project. This method is used as management considers expended cost to be the best available measure of progress on these contracts, the majority of which are completed within one year, but may occasionally extend beyond one year. Inherent uncertainties in estimating costs make it at least reasonably possible that the estimates used will change within the near term and over the life of the contracts. Contract costs include all direct material and labor costs and those indirect costs related to contract performance and completion. Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are estimable. General and administrative costs are charged to expense as incurred. Changes in job performance, job conditions and estimated profitability, including those arising from contract penalty provisions and final contract settlements, may result in revisions to costs and income. Such revisions are recognized in the period in which they are determined. An amount equal to contract costs incurred that are attributable to claims is included in revenue when realization is probable and the amount can be reliably estimated. Costs and estimated earnings in excess of billings are composed principally of revenue recognized on contracts (on the percentage-of-completion method) for which billings had not been presented to customers because the amount were not billable under the contract terms at the balance sheet date. In accordance with the contract terms, the unbilled receivables at December 27, 2014 will be billed in 2015. Billings in excess of costs and estimated earnings represent billings in excess of revenue recognized. Revenue from the receipt of waste fuels is classified as service revenue and is based on fees charged for the waste disposal, which are recognized when the waste is accepted.
Inventories		Inventories
Property, Plant and Equipment, net		Property, Plant and Equipment, net Landfill airspace is included in property, plant and equipment at cost and is amortized based on utilization of the asset. Management reassesses the landfill airspace capacity with any changes in value recorded in cost of revenue. Capitalized landfill costs include expenditures for the acquisition of land and related airspace, engineering and permitting costs, cell construction costs and direct site improvement costs. Upon disposal of an asset, the cost and related accumulated depreciation are removed from the Company’s accounts and any gain or loss is included in general and administrative expenses. Depreciation on property, plant and equipment, including assets subject to capital leases, is computed on a straight-line basis or based on the economic usage over the estimated useful life of the asset. The estimated useful lives are generally as follows: Buildings and improvements 7—40 years Plant, machinery and equipment 20—40 years Mobile equipment and barges 15—20 years Office equipment 3—6 years Truck and auto fleet 5—10 years Landfill airspace and improvements 5—60 years Other 2—10 years Depletion of mineral reserves is calculated for proven and probable reserves by the units of production method on a site-by-site basis. Leasehold improvements are amortized on a straight-line basis over the lesser of the asset’s useful life or the remaining lease term. The Company reviews the carrying value of property, plant and equipment for impairment whenever events or circumstances indicate that the carrying value of an asset may not be recoverable from the estimated future cash flows expected to result from its use and eventual disposition. Such indicators may include, among others, deterioration in general economic conditions, adverse changes in the markets in which an entity operates, increases in input costs that have a negative effect on earnings and cash flows or a trend of negative or declining cash flows over multiple periods. Property, plant and equipment is tested for impairment at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets. As a result, the property, plant and equipment impairment test is at a significantly lower level than the level at which goodwill is tested for impairment. In markets where the Company does not produce downstream products (e.g., ready-mixed concrete, asphalt paving mix and paving and related services), the lowest level of largely independent identifiable cash flows is at the individual aggregates operation or a group of aggregates operations collectively serving a local market or the cement operations, as a whole. Conversely, in vertically-integrated markets, the cash flows of the downstream and upstream businesses are not largely independently identifiable and the vertically-integrated operations are considered the lowest level of largely independent identifiable cash flows. In addition, assets are assessed for impairment charges when identified for disposition. Projected losses from disposition are recognized in the period in which they become estimable, which may be in advance of the actual disposition. The net loss from asset dispositions recognized in general and administrative expenses in fiscal years 2014, 2013 and 2012 was $6.5 million, $12.4 million and $2.6 million, respectively. No material impairment charges have been recognized on assets held for use in 2014, 2013 or 2012. The losses are commonly a result of the cash flows expected from selling the asset being less than the expected cash flows that could be generated from holding the asset for use.
Accrued Mining and Landfill Reclamation		Accrued Mining and Landfill Reclamation Significant changes in inflation rates or the amount or timing of future cost estimates typically result in both (1) a current adjustment to the recorded liability (and corresponding adjustment to the asset) and (2) a change in accretion of the liability and depreciation of the asset to be recorded prospectively over the remaining capacity of the unmined quarry or landfill.
Intangible Assets		Intangible Assets December 27, 2014 December 28, 2013 Gross Accumulated Net Gross Accumulated Net Leases $ 10,357 $ (2,031 ) $ 8,326 $ 10,430 $ (1,604 ) $ 8,826 Reserve rights 9,094 (540 ) 8,554 5,890 (221 ) 5,669 Trade names 1,020 (470 ) 550 1,020 (368 ) 652 Other 249 (32 ) 217 — — — Total intangible assets $ 20,720 $ (3,073 ) $ 17,647 $ 17,340 $ (2,193 ) $ 15,147 Amortization expense in 2014, 2013 and 2012 was $0.9 million, $0.8 million and $0.6 million, respectively. The estimated amortization expense for intangible assets for each of the next five years and thereafter is as follows: 2015 $ 3,105 2016 1,675 2017 956 2018 956 2019 956 Thereafter 9,999 Total $ 17,647
Goodwill		Goodwill
Income Taxes		Income Taxes The Company evaluates the tax positions taken on income tax returns that remain open to examination by the respective tax authorities from prior years and positions expected to be taken on the current year tax returns to identify uncertain tax positions. Interest and penalties are recorded in income tax expense.
Fair Value Measurements	Fair Value Measurements— September 26, 2015 December 27, 2014 Current portion of derivatives and acquisition-related liabilities: Contingent consideration $ 4,559 $ 2,375 Cash flow hedge 114 Derivatives and acquisition- related liabilities: Contingent consideration $ 2,711 $ 5,379 Cash flow hedge 897 The fair value of contingent consideration was 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. The fair value of the derivatives are based on observable, or Level 2, inputs such as interest rates, bond yields and prices in inactive markets. There were no material valuation adjustments in the three or nine months ended September 26, 2015 or September 27, 2014.	Fair Value Measurements Level 1 — Unadjusted quoted prices for identical assets or liabilities in active markets. Level 2 — Inputs other than Level 1 that are based on observable market data, either directly or indirectly. These include quoted prices for similar assets or liabilities in active markets, quoted prices for identical assets or liabilities in inactive markets, inputs that are observable that are not prices and inputs that are derived from or corroborated by observable markets. Level 3 — Valuations developed from unobservable data, reflecting the Company’s own assumptions, which market participants would use in pricing the asset or liability. Assets and liabilities measured at fair value in the consolidated balance sheets as of December 27, 2014 and December 28, 2013 are as follows: 2014 2013 Accrued expenses: Current portion of contingent consideration $ 2,375 $ — Acquisition- related liabilities Contingent consideration $ 5,379 $ 1,908 Certain acquisitions made by the Company require the payment of additional consideration contingent upon the achievement of specified operating results, referred to as contingent consideration or earn-out obligations. These payments will not be made if earn-out thresholds are not achieved. Approximately $4.5 million and $1.9 million of the increase in contingent consideration obligations relate to the January 17, 2014 acquisition of Alleyton Resource Corporation, Colorado Gulf, LP and certain assets of Barten Shepard Investments, LP (collectively, “Alleyton”) and the October 3, 2014 acquisition of Concrete Supply of Topeka, Inc. and all of the membership interests of Penny’s Concrete and Ready Mix, L.L.C. and Builders Choice Concrete Company of Missouri, L.L.C. (collectively, “Concrete Supply”), respectively. No material earn-out payments have been made to date. Summit Materials records contingent consideration at fair value on the acquisition date and then measures its fair value each reporting period. Any adjustments to fair value are recognized in earnings in the period identified. Management of the Company determines the appropriate policies and procedures to be used when determining the fair value of contingent consideration. Its fair values are based on unobservable inputs, or Level 3 assumptions, including projected probability-weighted cash payments and an 11.0% discount rate, which reflects the Company’s credit risk. 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 significantly lower, or higher, fair value measurement. In 2014 and 2012, we recognized immaterial reductions to contingent consideration of $0.5 million and $0.4 million, respectively.
Financial Instruments	Financial Instruments September 26, 2015 December 27, 2014 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt (1) $ 1,155,557 $ 1,156,193 $ 1,101,873 $ 1,064,917 Level 3 Current portion of deferred consideration and noncompete obligations (2) 13,132 13,132 16,027 16,027 Long term portion of deferred consideration and noncompete obligations (3) 30,609 30,609 37,357 37,357 (1) $8.1 million and $5.3 million included in current portion of debt as of September 26, 2015 and December 27, 2014, respectively. Excludes $60.0 million outstanding on the revolving credit facility as of September 26, 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.	Financial Instruments The fair value of long-term debt was approximately $1,101.9 million and $696.5 million as of December 27, 2014 and December 28, 2013, respectively, compared to its carrying value of $1,064.9 million and $663.0 million, respectively. Fair value was determined based on Level 2 inputs of the fair value hierarchy, including observable inputs, specifically quoted prices for these instruments in inactive markets. The fair value of Company’s revolving credit facility approximated its carrying value of $26.0 million at December 28, 2013. There were no outstanding borrowings on the revolving credit facility as of December 27, 2014.
Initial Public Offering	Initial Public Offering 1 2
Follow-On Offering	Follow-On Offering
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 September 26, 2015, the results of operations for the three and nine months ended September 26, 2015 and September 27, 2014 and cash flows for the nine months ended September 26, 2015 and September 27, 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 LLC and its subsidiaries, including noncontrolling interests. 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.
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 S34

Summary of Organization and Significant Accounting Policies (Tables)	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Accounting Policies [Abstract]
Estimated Useful Lives of Assets		The estimated useful lives are generally as follows: Buildings and improvements 7—40 years Plant, machinery and equipment 20—40 years Mobile equipment and barges 15—20 years Office equipment 3—6 years Truck and auto fleet 5—10 years Landfill airspace and improvements 5—60 years Other 2—10 years
Intangible Assets by Type and in Total		The following table shows intangible assets by type and in total: December 27, 2014 December 28, 2013 Gross Accumulated Net Gross Accumulated Net Leases $ 10,357 $ (2,031 ) $ 8,326 $ 10,430 $ (1,604 ) $ 8,826 Reserve rights 9,094 (540 ) 8,554 5,890 (221 ) 5,669 Trade names 1,020 (470 ) 550 1,020 (368 ) 652 Other 249 (32 ) 217 — — — Total intangible assets $ 20,720 $ (3,073 ) $ 17,647 $ 17,340 $ (2,193 ) $ 15,147
Estimated Amortization Expense for Intangible Assets		The estimated amortization expense for intangible assets for each of the next five years and thereafter is as follows: 2015 $ 3,105 2016 1,675 2017 956 2018 956 2019 956 Thereafter 9,999 Total $ 17,647
Schedule of Contingent Consideration Obligations Measured at Fair Value	The fair value of contingent consideration and derivatives as of September 26, 2015 and December 27, 2014 was: September 26, 2015 December 27, 2014 Current portion of derivatives and acquisition-related liabilities: Contingent consideration $ 4,559 $ 2,375 Cash flow hedge 114 Derivatives and acquisition- related liabilities: Contingent consideration $ 2,711 $ 5,379 Cash flow hedge 897	Assets and liabilities measured at fair value in the consolidated balance sheets as of December 27, 2014 and December 28, 2013 are as follows: 2014 2013 Accrued expenses: Current portion of contingent consideration $ 2,375 $ — Acquisition- related liabilities Contingent consideration $ 5,379 $ 1,908
Schedule of Carrying Value and Fair Value of Financial Instruments	The carrying value and fair value of these financial instruments as of September 26, 2015 and December 27, 2014 was: September 26, 2015 December 27, 2014 Fair Value Carrying Value Fair Value Carrying Value Level 2 Long-term debt (1) $ 1,155,557 $ 1,156,193 $ 1,101,873 $ 1,064,917 Level 3 Current portion of deferred consideration and noncompete obligations (2) 13,132 13,132 16,027 16,027 Long term portion of deferred consideration and noncompete obligations (3) 30,609 30,609 37,357 37,357 (1) $8.1 million and $5.3 million included in current portion of debt as of September 26, 2015 and December 27, 2014, respectively. Excludes $60.0 million outstanding on the revolving credit facility as of September 26, 2015. (2) Included in current portion of acquisition-related liabilities on the balance sheet. (3) Included in acquisition-related liabilities on the balance sheet.

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Business Combinations [Abstract]
Schedule of Supplemental Pro Forma Information of Acquisitions	The following unaudited supplemental pro forma information presents the financial results as if the Davenport Assets had been acquired on the first day of the 2014 fiscal year. This supplemental pro forma information has been prepared for comparative purposes and does not purport to be indicative of what would have occurred had the acquisition been made on the first day of the preceding fiscal year, nor is it indicative of any future results. The pro forma adjustments include a reduction of transaction costs of $6.5 million and additional depreciation, depletion, amortization and accretion of $7.5 million. Three months ended Nine months ended September 26, 2015 September 26, 2015 Revenue $ 477,706 $ 1,069,305 Net income 67,229 24,506	Pro Forma Financial Information (unaudited) Year ended December 27, 2014 December 28, 2013 December 29, 2012 Revenue $ 1,326,861 $ 1,230,491 $ 1,022,535 Net income (loss) 8,181 (104,705 ) (46,405 )
Summary of Assets Acquired and Liabilities Assumed	The following table summarizes aggregated information regarding the estimated fair values of the assets acquired and liabilities assumed in conjunction with the acquisition: September 26, 2015 Inventories $ 21,538 Property, plant and equipment 272,815 Other assets 6,537 Financial liabilities (1,509 ) Other long-term liabilities (95 ) Net assets acquired 299,286 Goodwill 150,710 Total consideration 449,996 Transfer of assets (2,182 ) Working capital true-up 896 Net cash paid for acquisitions $ 448,710	The following table summarizes aggregated information regarding the fair values of the assets acquired and liabilities assumed as of the respective acquisition dates in 2014, 2013 and 2012: Alleyton Year Ended Year Ended Year Ended Financial assets $ 15,489 $ 22,101 $ 8,302 $ 1,397 Inventories 2,548 8,249 3,954 6,988 Property, plant and equipment 47,985 74,687 40,580 21,543 Intangible assets(1) — 3,398 7,428 3,172 Other assets 2,595 3,337 52 1,330 Financial liabilities (10,054 ) (17,610 ) (6,164 ) (944 ) Other long-term liabilities (990 ) (11,727 ) (1,050 ) (364 ) Net assets acquired 57,573 82,435 53,102 33,122 Goodwill 147,064 148,838 16,120 26,230 Purchase price 204,637 231,273 69,222 59,352 Acquisition related liabilities (22,123 ) (10,656 ) (7,902 ) (10,547 ) Other (2,087 ) (3,190 ) 281 (48 ) Net cash paid for acquisitions $ 180,427 $ 217,427 $ 61,601 $ 48,757 (1) Intangible assets acquired in 2013 related to aggregate reserves to which the Company has the rights of ownership, but does not own the reserves ($5.9 million) and the differential between contractual lease rates and market rates for leases of aggregate reserves and office space. The acquired intangible assets in total, the reserve rights and the lease assets have weighted-average lives of 18 years, 20 years and 11 years, respectively.

Goodwill (Tables)

Goodwill (Tables)	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Recognition of the Goodwill Impairment Charges		After recognition of the goodwill impairment charges, the fair values of these reporting units’ goodwill recognized as of December 28, 2013 were: 2013 Goodwill: Utah operations in the West region $ 36,589 East region —
Goodwill by Reportable Segment and in Total	Changes in the carrying amount of goodwill, by reportable segment, from December 27, 2014 to September 26, 2015 are summarized as follows: West Central East Total Balance, December 27, 2014 $ 297,085 $ 96,025 $ 26,160 $ 419,270 Acquisitions (1) 4,579 150,929 — 155,508 Foreign currency translation adjustments (6,942 ) — — (6,942 ) Balance, September 26, 2015 $ 294,722 $ 246,954 $ 26,160 $ 567,836 (1) Includes certain working capital adjustments related to 2014 acquisitions	The following table presents goodwill by reportable segments and in total: West Central East Total Balance, December 29, 2012 $ 91,393 $ 72,789 $ 14,938 $ 179,120 Acquisitions 16,120 — — 16,120 Impairment (53,264 ) — (14,938 ) (68,202 ) Balance, December 28, 2013 54,249 72,789 — 127,038 Acquisitions 246,506 23,236 26,160 295,902 Foreign currency translation adjustments (3,670 ) — — (3,670 ) Balance, December 27, 2014 $ 297,085 $ 96,025 $ 26,160 $ 419,270

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 27, 2014
Discontinued Operations and Disposal Groups [Abstract]
Revenue and Loss before Income Tax Expense from Discontinued Operations	subject to federal or state income tax. The railroad, environmental remediation and concrete paving businesses’ revenue and loss before income taxes, including an immaterial gain on sale, in fiscal years 2014, 2013 and 2012 are summarized below: 2014 2013 2012 Total revenue $ 1,260 $ 3,884 $ 50,152 (Income) loss from discontinued operations before income taxes (71 ) 528 3,546

Accounts Receivable, Net (Table

Accounts Receivable, Net (Tables)	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Receivables [Abstract]
Summary of Accounts Receivable, Net	Accounts receivable, net consisted of the following as of September 26, 2015 and December 27, 2014: September 26, December 27, 2015 2014 Trade accounts receivable $ 194,235 $ 131,060 Retention receivables 13,396 12,053 Receivables from related parties 705 333 Accounts receivable 208,336 143,446 Less: Allowance for doubtful accounts (2,397 ) (2,144 ) Accounts receivable, net $ 205,939 $ 141,302	Accounts receivable, net consisted of the following as of December 27, 2014 and December 28, 2013: 2014 2013 Trade accounts receivable $ 131,060 $ 85,188 Retention receivables 12,053 15,966 Receivables from related parties 333 202 Accounts receivable 143,446 101,356 Less: Allowance for doubtful accounts (2,144 ) (2,019 ) Accounts receivable, net $ 141,302 $ 99,337

Inventories (Tables)

Inventories (Tables)	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Inventory Disclosure [Abstract]
Components of Inventories	Inventories consisted of the following as of September 26, 2015 and December 27, 2014: September 26, December 27, 2015 2014 Aggregate stockpiles $ 90,776 $ 88,211 Finished goods 11,284 8,826 Work in process 6,511 1,801 Raw materials 29,465 12,715 Total $ 138,036 $ 111,553	Inventories consisted of the following as of December 27, 2014 and December 28, 2013: 2014 2013 Aggregate stockpiles $ 88,211 $ 70,300 Finished goods 8,826 11,207 Work in process 1,801 2,623 Raw materials 12,715 12,302 Total $ 111,553 $ 96,432

Property, Plant and Equipment40

Property, Plant and Equipment, net (Tables)	12 Months Ended
	Dec. 27, 2014
Property, Plant and Equipment [Abstract]
Components of Property, Plant and Equipment	Property, plant and equipment, net consisted of the following as of December 27, 2014 and December 28, 2013: 2014 2013 Land (mineral bearing) and asset retirement costs $ 129,957 $ 107,007 Land (non-mineral bearing) 112,932 81,331 Buildings and improvements 86,702 77,535 Plants, machinery and equipment 622,466 553,113 Mobile equipment and barges 182,334 117,828 Office equipment 14,087 10,001 Truck and auto fleet 22,821 19,165 Landfill airspace and improvements 48,513 46,841 Construction in progress 8,445 29,560 Other 1,719 1,779 Property, plant and equipment 1,229,976 1,044,160 Less accumulated depreciation, depletion and amortization (279,375 ) (212,382 ) Property, plant and equipment, net $ 950,601 $ 831,778

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Payables and Accruals [Abstract]
Components of Accrued Expenses	Accrued expenses consisted of the following as of September 26, 2015 and December 27, 2014: September 26, December 27, 2015 2014 Interest $ 12,973 $ 32,475 Payroll and benefits 22,095 20,326 Capital lease obligations 16,065 17,530 Insurance 13,710 11,402 Non-income taxes 10,221 5,520 Professional fees 1,305 3,299 Other (1) 14,511 10,944 Total $ 90,880 $ 101,496 (1) Consists primarily of subcontractor and working capital settlement accruals.	Accrued expenses consisted of the following as of December 27, 2014 and December 28, 2013: 2014 2013 Interest $ 32,475 $ 17,294 Payroll and benefits 20,326 16,368 Capital lease obligations 17,530 2,068 Insurance 11,402 7,445 Non-income taxes 5,520 4,168 Professional fees 3,299 2,352 Other(1) 10,944 7,556 Total $ 101,496 $ 57,251 (1) Consists primarily of subcontractor and working capital settlement accruals.

Debt (Tables)

Debt (Tables)	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Debt Disclosure [Abstract]
Schedule of Debt	Debt consisted of the following as of September 26, 2015 and December 27, 2014: September 26, December 27, 2015 2014 Revolving credit facility $ 60,000 $ — Long-term debt: 10 1/2% Senior Notes, due 2020: $153.8 million senior notes, including a $5.5 million net premium at September 26, 2015 and $625.0 million senior notes, including a $26.5 million net premium at December 27, 2014 159,365 651,548 6 1/8% Senior Notes, due 2023: $350.0 million senior notes, issued at par at September 26, 2015 350,000 Term Loan, due 2022: $650.0 million term loan, net of $3.1 million discount at September 26, 2015 and $415.7 million term loan, net of $2.3 million discount at December 27, 2014 646,828 413,369 Total 1,156,193 1,064,917 Current portion of long-term debt 8,125 5,275 Long-term debt $ 1,148,068 $ 1,059,642	Debt as of December 27, 2014 and December 28, 2013 is summarized as follows: 2014 2013 Revolving credit facility $ — $ 26,000 Long-term debt: $625.0 million senior notes, including a $26.5 million net premium at December 27, 2014 and $250 million senior notes, net of $4.0 million discount at December 28, 2013 $ 651,548 $ 245,971 $415.7 million term loan, net of $2.3 million discount at December 27, 2014 and $419.9 million, net of $2.9 million discount at December 28, 2013 413,369 417,016 Total 1,064,917 662,987 Current portion of long-term debt 5,275 4,220 Long-term debt $ 1,059,642 $ 658,767
Schedule of Contractual Payments Long-Term Debt	The contractual payments of long-term debt, including current maturities, for the five years subsequent to September 26, 2015, are as follows: 2015 (three months) $ 3,250 2016 6,500 2017 6,500 2018 4,875 2019 6,500 2020 161,925 Thereafter 964,250 Total 1,153,800 Plus: Original issue net premium 2,393 Total debt $ 1,156,193	The total contractual payments of long-term debt for the five years subsequent to December 27, 2014 are as follows: 2015 $ 5,275 2016 4,220 2017 4,220 2018 3,165 2019 398,790 Thereafter 625,000 Total 1,040,670 Plus: Original issue net premium 24,247 Total debt $ 1,064,917
Summary of Activity for Deferred Financing Fees	The following table presents the activity for the deferred financing fees for the nine months ended September 26, 2015 and September 27, 2014: Deferred financing fees Balance — December 27, 2014 $ 17,215 Loan origination fees 10,911 Amortization (2,731 ) Write off of deferred financing fees (12,135 ) Balance — September 26, 2015 $ 13,260 Balance — December 28, 2013 $ 11,485 Loan origination fees 9,281 Amortization (2,875 ) Balance —September 27, 2014 $ 17,891

Accumulated Other Comprehensi43

Accumulated Other Comprehensive Loss (Tables)	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Equity [Abstract]
Accumulated Other Comprehensive Loss	The changes in each component of accumulated other comprehensive loss consisted of the following: Change in Foreign currency Cash flow hedge Accumulated Balance — December 27, 2014 $ (9,730 ) $ (5,816 ) $ — $ (15,546 ) Foreign currency translation adjustment — (11,531 ) — (11,531 ) Loss on cash flow hedges — — (1,010 ) (1,010 ) Balance — September 26, 2015 $ (9,730 ) $ (17,347 ) $ (1,010 ) $ (28,087 ) Balance — December 28, 2013 $ (6,045 ) $ — $ — $ (6,045 ) Postretirement curtailment adjustment (942 ) — — (942 ) Postretirement liability adjustment 1,515 — — 1,515 Foreign currency translation adjustment — (1,764 ) — (1,764 ) Balance —September 27, 2014 $ (5,472 ) $ (1,764 ) $ — $ (7,236 )	Change in Foreign currency Accumulated Balance—December 31, 2011 $ (6,577 ) $ (6,577 ) Postretirement liability adjustment (2,553 ) (2,553 ) Balance—December 29, 2012 (9,130 ) — (9,130 ) Postretirement liability adjustment 3,085 3,085 Balance—December 28, 2013 (6,045 ) — (6,045 ) Postretirement curtailment adjustment (942 ) — (942 ) Postretirement liability adjustment (2,743 ) — (2,743 ) Foreign currency translation adjustment — (5,816 ) (5,816 ) Balance—December 27, 2014 $ (9,730 ) $ (5,816 ) $ (15,546 )

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 27, 2014
Income Tax Disclosure [Abstract]
Components of Income Tax Benefit	For the years ended December 27, 2014, December 28, 2013 and December 31, 2012, income taxes consisted of the following: 2014 2013 2012 Provision for income taxes: Current $ (905 ) $ 1,761 $ (452 ) Deferred (6,078 ) (4,408 ) (3,468 ) Income tax benefit $ (6,983 ) $ (2,647 ) $ (3,920 )
Schedule of Income Tax Benefit	The effective tax rate on pre-tax income differs from the U.S. statutory rate due to the following: 2014 2013 2012 Income tax benefit at federal statutory tax rate $ (4,643 ) $ (37,160 ) $ (19,074 ) Less: Income tax benefit at federal statutory tax rate for LLC entities (2,272 ) 32,801 16,167 State and local income taxes (224 ) 130 (90 ) Depletion expense (129 ) (411 ) (377 ) Goodwill impairment — 1,046 — Effective rate change (241 ) — (532 ) Valuation allowance 1,693 729 36 Impact of international operations (73 ) — — Prior year true-up adjustments and amended returns (624 ) — — Other (470 ) 218 (50 ) Income tax benefit $ (6,983 ) $ (2,647 ) $ (3,920 )
Components of Net Deferred Income Tax Liability	The following table summarizes the components of the net deferred income tax liability as December 27, 2014 and December 28, 2013: 2014 2013 Deferred tax (liabilities) assets: Accelerated depreciation $ (40,141 ) $ (33,146 ) Mining reclamation reserve 2,180 1,502 Net operating loss 7,106 2,227 Capital losses on securities — 997 Net intangible assets (1,072 ) (607 ) Inventory purchase accounting adjustments 1,275 1,288 Working capital (e.g., accrued compensation, prepaid assets) (10 ) 1,655 Deferred tax liabilities, net (30,662 ) (26,084 ) Less valuation allowance on loss carryforwards (2,523 ) (1,826 ) Total $ (33,185 ) $ (27,910 )

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 27, 2014
Postemployment Benefits [Abstract]
Obligations and Funded Status	Obligations and Funded Status 2014 2013 Pension Healthcare Pension Healthcare Change in benefit obligations: Beginning of period $ 25,644 $ 14,155 $ 28,674 $ 15,810 Service cost 75 106 295 236 Interest cost 1,081 493 963 513 Actuarial loss (gain) 3,798 1,992 (2,674 ) (1,048 ) Special termination benefits — — — 39 Change in plan provision — (2,553 ) — — Benefits paid (1,689 ) (837 ) (1,614 ) (1,395 ) End of period 28,909 13,356 25,644 14,155 Change in fair value of plan assets: Beginning of period $ 19,074 $ — $ 17,863 $ — Actual return on plan assets 526 — 1,512 — Employer contributions 961 837 1,313 1,395 Benefits paid (1,689 ) (837 ) (1,614 ) (1,395 ) End of period 18,872 — 19,074 — Funded status of plans $ (10,037 ) $ (13,356 ) $ (6,570 ) $ (14,155 ) Current liabilities $ — $ (1,041 ) $ — $ (1,268 ) Noncurrent liabilities (10,037 ) (12,315 ) (6,570 ) (12,887 ) Liability recognized $ (10,037 ) $ (13,356 ) $ (6,570 ) $ (14,155 ) Amounts recognized in accumulated other comprehensive loss: Net actuarial loss $ 9,365 $ 5,904 $ 4,831 $ 4,139 Prior service cost — (2,380 ) — (1,346 ) Total amount recognized $ 9,365 $ 3,524 $ 4,831 $ 2,793
Amounts Recognized in Other Comprehensive (Gain) Loss	2014 2013 2012 Pension Healthcare Pension Healthcare Pension Healthcare Amounts recognized in other comprehensive loss (income): Net actuarial gain (loss) $ 4,650 $ 1,992 $ (2,838 ) $ (1,048 ) $ 2,444 $ 1,597 Prior service cost — (2,553 ) — — — — Amortization of prior year service cost — 174 — 180 — 180 Curtailment benefit — 1,346 — — — — Amortization of gain (117 ) (227 ) (387 ) (314 ) (261 ) (312 ) Total amount recognized $ 4,533 $ 732 $ (3,225 ) $ (1,182 ) $ 2,183 $ 1,465
Components of Net Periodic Benefit Cost	2014 2013 2012 Pension Healthcare Pension Healthcare Pension Healthcare Amounts recognized in other comprehensive loss (income): Net actuarial gain (loss) $ 4,650 $ 1,992 $ (2,838 ) $ (1,048 ) $ 2,444 $ 1,597 Prior service cost — (2,553 ) — — — — Amortization of prior year service cost — 174 — 180 — 180 Curtailment benefit — 1,346 — — — — Amortization of gain (117 ) (227 ) (387 ) (314 ) (261 ) (312 ) Total amount recognized $ 4,533 $ 732 $ (3,225 ) $ (1,182 ) $ 2,183 $ 1,465 Components of net periodic benefit cost: Service cost $ 75 $ 106 $ 295 $ 236 $ 276 $ 207 Interest cost 1,081 493 963 513 1,055 585 Amortization of loss 117 227 387 314 261 312 Expected return on plan assets (1,378 ) — (1,348 ) — (1,300 ) (180 ) Curtailment benefit — (1,346 ) — — — — Special termination benefits — — — 39 — — Amortization of prior service credit — (174 ) — (180 ) — — Net periodic benefit cost $ (105 ) $ (694 ) $ 297 $ 922 $ 292 $ 924
Weighted-Average Assumptions Used to Determine Benefit Obligations	Assumptions— 2014 2013 Pension benefits Healthcare Pension benefits Healthcare Discount rate 3.50% - 3.65% 3.52% 4.21% - 4.46% 4.33% Expected long-term rate of return on plan assets 7.30% N/A 7.50% N/A
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost	Weighted-average assumptions used to determine net periodic benefit cost for years ended December 27, 2014, December 28, 2013 and December 29, 2012: 2014 2013 2012 Pension benefits Healthcare Pension benefits Healthcare Pension benefits Healthcare Discount rate 4.21% - 4.46% 4.33% 3.30% - 3.57% 3.41% 3.89% - 4.07% 4.00% Expected long-term rate of return on plan assets 7.50% N/A 7.50% N/A 7.50% N/A
Effects of One Percentage-Point Change in Assumed Health Care Cost Trend Rates	A one percentage-point change in assumed health care cost trend rates would have the following effects as of year-end 2014 and 2013: 2014 2013 Increase Decrease Increase Decrease Total service cost and interest cost components $ 39 $ (34 ) $ 66 $ (55 ) APBO 1,333 (1,136 ) 1,251 (1,073 )
Fair Value of Company's Pension Plans' Assets	The fair value of the Plans’ assets by asset class and fair value hierarchy level as of December 27, 2014 and December 28, 2013 are as follows: 2014 Total fair Quoted prices in active Observable Fixed income securities: Intermediate—government $ 1,468 $ — $ 1,468 Intermediate—corporate 3,342 — 3,342 Short-term—government 2,435 — 2,435 Short-term—corporate 3,700 — 3,700 Equity securities: U.S. Large cap value 1,180 1,180 — U.S. Large cap growth 1,173 1,173 — U.S. Mid cap value 590 590 — U.S. Mid cap growth 598 598 — U.S. Small cap value 597 597 — U.S. Small cap growth 611 611 — International 1,098 1,098 — Cash 1,712 1,712 — Precious metals 368 368 — Total $ 18,872 $ 7,927 $ 10,945 2013 Total fair Quoted prices in active Observable Fixed income securities: Intermediate—government $ 1,647 $ — $ 1,647 Intermediate—corporate 3,138 — 3,138 Short-term—government 2,168 — 2,168 Short-term—corporate 4,040 — 4,040 Equity securities: U.S. Large cap value 1,221 1,221 — U.S. Large cap growth 1,536 1,536 — U.S. Mid cap value 600 600 — U.S. Mid cap growth 603 603 — U.S. Small cap value 610 610 — U.S. Small cap growth 599 599 — International 889 889 — Cash 1,665 1,665 — Precious metals 358 358 — Total $ 19,074 $ 8,081 $ 10,993
Estimated Benefit Payments	The estimated benefit payments for each of the next five years and the five-year period thereafter are as follows: Pension Healthcare and Life 2015 $ 1,715 $ 1,041 2016 1,743 1,015 2017 1,740 893 2018 1,773 893 2019 1,777 823 2020 - 2024 8,524 3,912 Total $ 17,272 $ 8,577

Accrued Mining and Landfill R46

Accrued Mining and Landfill Reclamation (Tables)	12 Months Ended
	Dec. 27, 2014
Asset Retirement Obligation Disclosure [Abstract]
Activity for Asset Retirement Obligations	remaining useful life. The following table presents the activity for the asset retirement obligations for the years ended December 27, 2014 and December 28, 2013: 2014 2013 Beginning balance $ 15,781 $ 14,844 Acquired obligations 140 286 Change in cost estimate 2,233 721 Settlement of reclamation obligations (1,178 ) (1,201 ) Additional liabilities incurred 463 414 Accretion expense 871 717 Ending balance $ 18,310 $ 15,781

Acquisition-Related Liabiliti47

Acquisition-Related Liabilities (Tables)	12 Months Ended
	Dec. 27, 2014
Business Combinations [Abstract]
Remaining Payments Due under Noncompete and Deferred Consideration Agreements	The remaining payments due under these noncompete and deferred consideration agreements are as follows: 2015 $ 16,051 2016 13,240 2017 10,200 2018 9,660 2019 5,435 Thereafter 16,272 Total scheduled payments 70,858 Present value adjustments (17,474 ) Total noncompete obligations and deferred consideration $ 53,384

Supplemental Cash Flow Inform48

Supplemental Cash Flow Information (Tables)	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Supplemental Cash Flow Elements [Abstract]
Schedule of Supplemental Cash Flow Information	Supplemental cash flow information is as follows: Nine months ended September 26, September 27, 2015 2014 Cash payments: Interest $ 75,990 $ 59,179 Income taxes 1,516 1,345 Non cash financing activities: Purchase of noncontrolling interest in Continental Cement $ (64,102 ) $ —	Supplemental cash flow information for the years ended December 27, 2014, December 28, 2013 and December 29, 2012 was as follows: 2014 2013 2012 Cash payments: Interest $ 64,097 $ 52,001 $ 36,357 Income taxes 1,361 457 799

Leasing Arrangements (Tables)

Leasing Arrangements (Tables)	12 Months Ended
	Dec. 27, 2014
Leases [Abstract]
Minimum Contractual Commitments under Long-Term Operating Leases	Minimum contractual commitments under long-term operating leases, which primarily relate to land, plant and equipment, and under royalty agreements as of December 27, 2014, are as follows: Operating Royalty 2015 $ 5,048 $ 3,303 2016 4,061 4,711 2017 3,223 4,973 2018 2,018 4,522 2019 1,469 4,265

Employee Long Term Incentive 50

Employee Long Term Incentive Plan (Tables)	12 Months Ended
	Dec. 27, 2014
Contractors [Abstract]
Summary of Information for Class D Unit Interests	The following table summarizes information for the Class D unit interests: Time-vesting Interests Performance-vesting Number of Weighted Number of Weighted Beginning balance—December 28, 2013 1,819 $ 2,929 4,877 $ 2,928 Granted 410 1,368 533 1,956 Vested (1,070 ) 3,553 — — Cancelled (280 ) 3,938 (48 ) 1,388 Balance—December 27, 2014 879 2,374 5,362 $ 2,845
Weighted Average Assumptions Used to Estimate the Fair Value of Grants	The following table presents the weighted average assumptions used to estimate the fair value of grants in 2014, 2013 and 2012: 2014 2013 2012 Class D Units Risk-free interest rate 0.50% - 0.68% 0.50% 1.62% Dividend yield None None None Volatility 58% 58% 47% Expected term 3 - 4 years 4 years 6 - 8 years

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Segment Reporting [Abstract]
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 Nine months ended September 26, September 27, September 26, September 27, 2015 2014 2015 2014 Revenue: West region $ 261,742 $ 211,302 $ 597,484 $ 478,432 Central region 164,084 126,882 338,613 283,541 East region 46,079 56,575 94,738 108,172 Total revenue $ 471,905 $ 394,759 $ 1,030,835 $ 870,145 Three months ended Nine months ended September 26, September 27, September 26, September 27, 2015 2014 2015 2014 Adjusted EBITDA West region $ 59,574 $ 39,105 $ 110,940 $ 71,646 Central region 53,756 30,820 89,984 59,220 East region 13,383 11,868 15,096 10,462 Corporate and other (8,879 ) (9,381 ) (33,577 ) (28,427 ) Total reportable segments and corporate 117,834 72,412 182,443 112,901 Interest expense 20,436 22,085 61,649 62,555 Depreciation, depletion, amortization and accretion 33,306 23,255 86,818 63,950 Initial public offering costs — — 28,296 — Loss on debt financings 32,641 — 64,313 — Income (loss) from continuing operations before taxes $ 31,451 $ 27,072 $ (58,633 ) $ (13,604 ) Nine months ended September 26, September 27, 2015 2014 Cash paid for capital expenditures: West region $ 32,192 $ 25,496 Central region 24,335 28,485 East region 9,401 6,590 Total reportable segments 65,928 60,571 Corporate and other 3,744 3,673 Total capital expenditures $ 69,672 $ 64,244 Three months ended Nine months ended September 26, September 27, September 26, September 27, 2015 2014 2015 2014 Depreciation, depletion, amortization and accretion: West region $ 13,786 $ 9,155 $ 38,508 $ 23,569 Central region 15,778 9,710 37,198 28,061 East region 3,114 3,984 9,426 11,272 Total reportable segments 32,678 22,849 85,132 62,902 Corporate and other 628 406 1,686 1,048 Total depreciation, depletion, amortization and accretion $ 33,306 $ 23,255 $ 86,818 $ 63,950 September 26, December 27, 2015 2014 Total assets: West region $ 866,516 $ 777,981 Central region 1,189,565 704,134 East region 224,720 221,598 Total reportable segments 2,280,801 1,703,713 Corporate and other 35,935 26,064 Total $ 2,316,736 $ 1,729,777 Three months ended Nine months ended September 26, September 27, September 26, September 27, 2015 2014 2015 2014 Revenue by product:* Aggregates $ 86,070 $ 68,636 $ 218,336 $ 160,002 Cement 68,481 34,171 110,477 69,435 Ready-mixed concrete 95,481 75,429 254,878 189,198 Asphalt 113,249 104,862 219,492 203,944 Paving and related services 185,092 191,157 366,321 391,925 Other (76,468 ) (79,496 ) (138,669 ) (144,359 ) Total revenue $ 471,905 $ 394,759 $ 1,030,835 $ 870,145 * 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.	The following tables display selected financial data for the Company’s reportable business segments as of and for the years ended December 27, 2013, December 28, 2013 and December 29, 2012: 2014 2013 2012 Revenue: West region $ 665,716 $ 426,195 $ 484,922 Central region 391,553 329,621 302,113 East region 146,962 160,385 139,219 Total revenue $ 1,204,231 $ 916,201 $ 926,254 2014 2013 2012 Adjusted EBITDA West region $ 96,133 $ 28,607 $ 14,429 Central region 83,912 72,918 65,767 East region 17,955 15,134 10,782 Corporate and other (36,768 ) (24,878 ) (15,560 ) Total reportable segments and corporate 161,232 91,781 75,418 Interest expense 86,742 56,443 58,079 Depreciation, depletion, amortization and accretion 87,826 72,934 68,290 Goodwill impairment — 68,202 — Loss from continuing operations before taxes $ (13,336 ) $ (105,798 ) $ (50,951 ) 2014 2013 2012 Cash paid for capital expenditures: West region $ 31,968 $ 21,856 $ 14,993 Central region 32,114 33,030 20,996 East region 7,547 7,753 8,736 Total reportable segments 71,629 62,639 44,725 Corporate and other 4,533 3,360 763 Total capital expenditures $ 76,162 $ 65,999 $ 45,488 2014 2013 2012 Depreciation, depletion, amortization and accretion: West region $ 33,271 $ 24,167 $ 23,771 Central region 38,793 33,808 30,215 East region 14,294 14,493 14,223 Total reportable segments 86,358 72,468 68,209 Corporate and other 1,468 466 81 Total depreciation, depletion, amortization and accretion $ 87,826 $ 72,934 $ 68,290 2014 2013 2012 Total assets: West region $ 777,981 $ 383,544 $ 428,115 Central region 704,134 657,421 610,003 East region 221,598 192,486 224,603 Total reportable segments 1,703,713 1,233,451 1,262,721 Corporate and other 26,064 14,343 21,758 Total $ 1,729,777 $ 1,247,794 $ 1,284,479 2014 2013 2012 Revenue by product:* Aggregates $ 229,047 $ 159,019 $ 146,991 Cement 89,911 76,211 77,676 Ready-mixed concrete 274,970 112,878 100,941 Asphalt 278,867 219,811 242,458 Paving and related services 528,817 478,280 505,189 Other (197,381 ) (129,998 ) (147,001 ) Total revenue $ 1,204,231 $ 916,201 $ 926,254 * Revenue by product includes intracompany sales transferred at market value. The elimination of intracompany transactions is included in Other.

Guarantor and Non-Guarantor F52

Guarantor and Non-Guarantor Financial Information (Tables)	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Consolidating Balance Sheets	Condensed Consolidating Balance Sheets September 26, 2015 Issuers Wholly- Non- Eliminations Consolidated Assets Current assets: Cash and cash equivalents $ 8,989 $ 1,025 $ 8,130 $ (12,662 ) $ 5,482 Accounts receivable, net — 195,120 11,163 (344 ) 205,939 Intercompany receivables 1,322,050 14,869 8,996 (1,345,915 ) — Cost and estimated earnings in excess of billings — 33,447 728 — 34,175 Inventories — 132,734 5,302 — 138,036 Other current assets 1,088 19,319 1,355 — 21,762 Total current assets 1,332,127 396,514 35,674 (1,358,921 ) 405,394 Property, plant and equipment, net 9,433 1,240,126 26,668 — 1,276,227 Goodwill — 519,759 48,077 — 567,836 Intangible assets, net — 14,044 1,437 — 15,481 Other assets 881,923 132,532 1,271 (963,928 ) 51,798 Total assets $ 2,223,483 $ 2,302,975 $ 113,127 $ (2,322,849 ) $ 2,316,736 Liabilities, Redeemable Noncontrolling Interest and Member’s Interest Current liabilities: Current portion of debt $ 68,125 $ — $ — $ — $ 68,125 Current portion of acquisition-related liabilities — 17,691 — — 17,691 Accounts payable 7,436 102,571 3,563 (344 ) 113,226 Accrued expenses 30,998 70,386 2,158 (12,662 ) 90,880 Intercompany payables 67,671 1,274,510 3,734 (1,345,915 ) — Billings in excess of costs and estimated earnings — 10,983 22 — 11,005 Total current liabilities 174,230 1,476,141 9,477 (1,358,921 ) 300,927 Long-term debt 1,148,068 61,377 — (61,377 ) 1,148,068 Acquisition-related liabilities — 33,320 — — 33,320 Other noncurrent liabilities 1,558 110,856 57,268 (55,107 ) 114,575 Total liabilities 1,323,856 1,681,694 66,745 (1,475,405 ) 1,596,890 Redeemable noncontrolling interest — — — — — Redeemable members’ interest — — — — — Total stockholders’ equity/partners’ interest 899,627 621,281 46,382 (847,444 ) 719,846 Total liabilities, redeemable noncontrolling interest and member’s interest $ 2,223,483 $ 2,302,975 $ 113,127 $ (2,322,849 ) $ 2,316,736 Condensed Consolidating Balance Sheets December 27, 2014 Issuers Non- Wholly- Wholly- Non- Elim- inations Consol- idated Assets Current assets: Cash and cash equivalents $ 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 Balance Sheets December 27, 2014 Issuers Non- wholly- owned 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 member’s 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 Balance Sheets December 28, 2013 Issuers Non- wholly- owned Wholly- Non- Eliminations Consolidated Assets Current assets: Cash $ 10,375 $ 9 $ 3,442 $ 3,631 $ (2,540 ) $ 14,917 Accounts receivable, net — 4,587 93,102 3,100 (1,452 ) 99,337 Intercompany receivables 38,134 3,433 30,787 — (72,354 ) — Cost and estimated earnings in excess of billings — — 10,539 228 — 10,767 Inventories — 10,402 85,372 658 — 96,432 Other current assets 750 444 11,715 272 — 13,181 Total current assets 49,259 18,875 234,957 7,889 (76,346 ) 234,634 Property, plant and equipment, net 3,969 301,908 518,935 6,966 — 831,778 Goodwill — 23,124 102,942 972 — 127,038 Intangible assets, net — 642 14,505 — — 15,147 Other assets 296,494 17,973 37,535 1,303 (314,108 ) 39,197 Total assets $ 349,722 $ 362,522 $ 908,874 $ 17,130 $ (390,454 ) $ 1,247,794 Liabilities, Redeemable Noncontrolling Interest and Member’s Interest Current liabilities: Current portion of debt $ 26,010 $ 1,018 $ 3,192 $ — $ — $ 30,220 Current portion of acquisition-related liabilities 2,000 — 8,635 — — 10,635 Accounts payable 5,455 9,387 57,142 1,572 (1,452 ) 72,104 Accrued expenses 12,041 9,185 37,342 1,223 (2,540 ) 57,251 Intercompany payables — — 71,556 798 (72,354 ) — Billings in excess of costs and estimated earnings — — 8,837 426 — 9,263 Total current liabilities 45,506 19,590 186,704 4,019 (76,346 ) 179,473 Long-term debt 19,587 154,590 484,590 — — 658,767 Acquisition-related liabilities 85 — 23,671 — — 23,756 Other noncurrent liabilities 959 20,306 56,215 — — 77,480 Total liabilities 66,137 194,486 751,180 4,019 (76,346 ) 939,476 Redeemable noncontrolling interest — — — — 24,767 24,767 Redeemable members’ interest — 23,450 — — (23,450 ) — Total member’s interest 283,585 144,586 157,694 13,111 (315,425 ) 283,551 Total liabilities, redeemable noncontrolling interest and member’s interest $ 349,722 $ 362,522 $ 908,874 $ 17,130 $ (390,454 ) $ 1,247,794
Condensed Consolidating Statements of Operations	For the three months ended September 26, 2015 Issuers Wholly- Non- Eliminations Consolidated Revenue $ — $ 454,501 $ 21,472 $ (4,068 ) $ 471,905 Cost of revenue (excluding items shown separately below) — 304,204 12,263 (4,068 ) 312,399 General and administrative expenses 8,881 32,362 1,600 — 42,843 Depreciation, depletion, amortization and accretion 628 31,374 1,304 — 33,306 Operating (loss) income (9,509 ) 86,561 6,305 — 83,357 Other (income) expense, net (58,666 ) 3,639 (17 ) 86,514 31,470 Interest expense 15,046 15,286 900 (10,796 ) 20,436 Income from continuing operations before taxes 34,111 67,636 5,422 (75,718 ) 31,451 Income tax benefit (expense) — (2,690 ) 35 — (2,655 ) Income from continuing operations 34,111 70,326 5,387 (75,718 ) 34,106 Income from discontinued operations — (57 ) — — (57 ) Net income 34,111 70,383 5,387 (75,718 ) 34,163 Net income attributable to minority interest — — — 52 52 Net income attributable to member of Summit Materials, LLC $ 34,111 $ 70,383 $ 5,387 $ (75,770 ) $ 34,111 Comprehensive income attributable to member of Summit Materials, LLC $ 26,805 $ 69,373 $ (909 ) $ (68,464 ) $ 26,805 Condensed Consolidating Statements of Operations For the three months ended September 27, 2014 Issuers Non- Wholly- Wholly- Non- Elim- Consol- Revenue $ — $ 34,171 $ 348,785 $ 22,626 $ (10,823 ) $ 394,759 Cost of revenue (excluding items shown separately below) — 25,603 253,284 17,433 (10,823 ) 285,497 General and administrative expenses 8,694 1,651 27,418 495 — 38,258 Depreciation, depletion, amortization and accretion 406 3,708 18,618 523 — 23,255 Operating (loss) income (9,100 ) 3,209 49,465 4,175 — 47,749 Other (income) expense, net (43,887 ) (945 ) (2,679 ) (16 ) 46,119 (1,408 ) Interest expense 7,913 2,931 13,416 233 (2,408 ) 22,085 Income from continuing operations before taxes 26,874 1,223 38,728 3,958 (43,711 ) 27,072 Income tax benefit (expense) — — (1,038 ) — — (1,038 ) Income from continuing operations 26,874 1,223 39,766 3,958 (43,711 ) 28,110 Income from discontinued operations — — (7 ) — — (7 ) Net income 26,874 1,223 39,773 3,958 (43,711 ) 28,117 Net income attributable to minority interest — — — — 1,243 1,243 Net income attributable to member of Summit Materials, LLC $ 26,874 $ 1,223 $ 39,773 $ 3,958 $ (44,954 ) $ 26,874 Comprehensive income attributable to member of Summit Materials, LLC $ 25,110 $ 1,223 $ 39,773 $ 2,194 $ (43,190 ) $ 25,110 Condensed Consolidating Statements of Operations For the nine months ended September 26, 2015 Issuers Wholly- Non- Eliminations Consolidated Revenue $ — $ 980,153 $ 78,821 $ (28,139 ) $ 1,030,835 Cost of revenue (excluding items shown separately below) — 696,068 51,909 (28,139 ) 719,838 General and administrative expenses 61,634 90,959 4,935 — 157,528 Depreciation, depletion, amortization and accretion 1,686 80,997 4,135 — 86,818 Operating (loss) income (63,320 ) 112,129 17,842 — 66,651 Other (income) expense, net (55,083 ) 7,140 142 111,436 63,635 Interest expense 35,196 45,332 2,689 (21,568 ) 61,649 Income from continuing operations before taxes (43,433 ) 59,657 15,011 (89,868 ) (58,633 ) Income tax benefit (expense) — (12,852 ) 384 — (12,468 ) Income from continuing operations (43,433 ) 72,509 14,627 (89,868 ) (46,165 ) Income from discontinued operations — (815 ) — — (815 ) Net income (43,433 ) 73,324 14,627 (89,868 ) (45,350 ) Net income attributable to minority interest — — — (1,917 ) (1,917 ) Net income attributable to member of Summit Materials, LLC $ (43,433 ) $ 73,324 $ 14,627 $ (87,951 ) $ (43,433 ) Comprehensive income attributable to member of Summit Materials, LLC $ (55,974 ) $ 72,314 $ 3,096 $ (75,410 ) $ (55,974 ) Condensed Consolidating Statements of Operations For the nine months ended September 27, 2014 Issuers Non- Wholly- Wholly- Non- Elim- Consol- Revenue $ — $ 69,435 $ 776,502 $ 43,900 $ (19,692 ) $ 870,145 Cost of revenue (excluding items shown separately below) — 53,229 581,602 30,795 (19,692 ) 645,934 General and administrative expenses 26,384 5,225 80,938 1,062 — 113,609 Depreciation, depletion, amortization and accretion 1,047 10,484 51,351 1,068 — 63,950 Operating (loss) income (27,431 ) 497 62,611 10,975 — 46,652 Other expense (income), net (36,161 ) (2,303 ) (4,233 ) 29 40,369 (2,299 ) Interest expense 21,581 8,788 37,831 289 (5,934 ) 62,555 (Loss) income from continuing operations before taxes (12,851 ) (5,988 ) 29,013 10,657 (34,435 ) (13,604 ) Income tax benefit (1,427 ) — (1,071 ) — — (2,498 ) (Loss) income from continuing operations (11,424 ) (5,988 ) 30,084 10,657 (34,435 ) (11,106 ) Income from discontinued operations — — (356 ) — — (356 ) Net (loss) income (11,424 ) (5,988 ) 30,440 10,657 (34,435 ) (10,750 ) Net loss attributable to noncontrolling interest — — — — 674 674 Net (loss) income attributable to member of Summit Materials, LLC $ (11,424 ) $ (5,988 ) $ 30,440 $ 10,657 $ (35,109 ) $ (11,424 ) Comprehensive (loss) income attributable to member of Summit Materials, LLC $ (12,615 ) (5,170 ) $ 30,440 $ 8,893 $ (34,163 ) $ (12,615 )	Condensed Consolidating Statements of Operations and Comprehensive Loss Year ended December 27, 2014 Issuers Non- wholly- owned Guarantor Wholly- Non- Eliminations Consolidated Total revenue $ — $ 94,402 $ 1,065,590 $ 72,172 $ (27,933 ) $ 1,204,231 Cost of revenue (excluding items shown separately below) — 67,951 796,078 51,064 (27,933 ) 887,160 General and administrative expenses 30,736 6,763 119,250 2,537 — 159,286 Depreciation, depletion, amortization and accretion 1,468 14,500 70,116 1,742 — 87,826 Operating (loss) income (32,204 ) 5,188 80,146 16,829 — 69,959 Other (income) expense, net (53,827 ) (14,444 ) (6,687 ) (3 ) 71,514 (3,447 ) Interest expense 31,827 11,608 51,248 1,172 (9,113 ) 86,742 (Loss) income from continuing operations before taxes (10,204 ) 8,024 35,585 15,660 (62,401 ) (13,336 ) Income tax benefit (1,427 ) — (5,766 ) 210 — (6,983 ) (Loss) income from continuing operations (8,777 ) 8,024 41,351 15,450 (62,401 ) (6,353 ) Income from discontinued operations — — (71 ) — — (71 ) Net (loss) income (8,777 ) 8,024 41,422 15,450 (62,401 ) (6,282 ) Net loss attributable to noncontrolling interest — — — — 2,495 2,495 Net (loss) income attributable to member of Summit Materials, LLC $ (8,777 ) $ 8,024 $ 41,422 $ 15,450 $ (64,896 ) $ (8,777 ) Comprehensive (loss) income attributable to member of Summit Materials, LLC $ (18,278 ) $ 2,759 $ 41,422 $ 9,634 $ (53,815 ) $ (18,278 ) Condensed Consolidating Statements of Operations and Comprehensive Loss Year ended December 28, 2013 Summit Non- wholly- owned Wholly- Non- Eliminations Consolidated Total revenue $ — $ 80,759 $ 807,921 $ 41,910 $ (14,389 ) $ 916,201 Cost of revenue (excluding items shown separately below) — 55,241 611,799 24,401 (14,389 ) 677,052 General and administrative expenses 7,241 7,673 129,768 1,308 — 145,990 Goodwill impairment — — 68,202 — — 68,202 Depreciation, depletion, amortization and accretion 465 11,378 60,078 1,013 — 72,934 Operating (loss) income (7,706 ) 6,467 (61,926 ) 15,188 — (47,977 ) Other expense (income), net 99,085 (3,737 ) (3,410 ) 274 (90,834 ) 1,378 Interest expense — 10,702 49,591 382 (4,232 ) 56,443 (Loss) income from continuing operations before taxes (106,791 ) (498 ) (108,107 ) 14,532 95,066 (105,798 ) Income tax expense — — (2,647 ) — — (2,647 ) (Loss) income from continuing operations (106,791 ) (498 ) (105,460 ) 14,532 95,066 (103,151 ) Loss from discontinued operations — — 528 — — 528 Net (loss) income (106,791 ) (498 ) (105,988 ) 14,532 95,066 (103,679 ) Net income attributable to noncontrolling interest — — — — 3,112 3,112 Net (loss) income attributable to member of Summit Materials, LLC $ (106,791 ) $ (498 ) $ (105,988 ) $ 14,532 $ 91,954 $ (106,791 ) Comprehensive (loss) income attributable to member of Summit Materials, LLC $ (106,791 ) $ 3,909 $ (105,988 ) $ 14,532 $ 90,632 $ (103,706 ) Condensed Consolidating Statements of Operations and Comprehensive Loss Year ended December 29, 2012 Summit Non- wholly- owned Wholly- Non- Eliminations Consolidated Total revenue $ — $ 81,516 $ 824,796 $ 33,074 $ (13,132 ) $ 926,254 Cost of revenue (excluding items shown separately below) — 58,319 649,577 18,582 (13,132 ) 713,346 General and administrative expenses 8 6,235 121,633 1,327 — 129,203 Depreciation, depletion, amortization and accretion 81 10,093 57,080 1,036 — 68,290 Operating (loss) income (89 ) 6,869 (3,494 ) 12,129 — 15,415 Other expense (income), net 52,400 (2,065 ) 6,630 (101 ) (48,577 ) 8,287 Interest expense — 12,045 47,293 633 (1,892 ) 58,079 (Loss) income from continuing operations before taxes (52,489 ) (3,111 ) (57,417 ) 11,597 50,469 (50,951 ) Income tax expense 5 — (3,925 ) — — (3,920 ) (Loss) income from continuing operations (52,494 ) (3,111 ) (53,492 ) 11,597 50,469 (47,031 ) Loss from discontinued operations — — 3,546 — — 3,546 Net (loss) income (52,494 ) (3,111 ) (57,038 ) 11,597 50,469 (50,577 ) Net income attributable to noncontrolling interest — — — — 1,919 1,919 Net (loss) income attributable to member of Summit Materials, LLC $ (52,494 ) $ (3,111 ) $ (57,038 ) $ 11,597 $ 48,550 $ (52,496 ) Comprehensive (loss) income attributable to member of Summit Materials, LLC $ (52,494 ) $ (6,759 ) $ (57,038 ) $ 11,597 $ 49,645 $ (55,049 )
Condensed Consolidating Statements of Cash Flows	Condensed Consolidating Statements of Cash Flows For the nine months ended September 26, 2015 Issuers Wholly- Non- Elim- Consol- Net cash (used in) provided by operating activities $ (140,504 ) $ 112,541 $ 9,203 $ (167 ) $ (18,927 ) Cash flow from investing activities: Acquisitions, net of cash acquired — (505,466 ) — — (505,466 ) Purchase of property, plant and equipment (3,743 ) (65,001 ) (928 ) — (69,672 ) Proceeds from the sale of property, plant, and equipment — 8,821 62 — 8,883 Other — 610 — — 610 Net cash used for investing activities (3,743 ) (561,036 ) (866 ) — (565,645 ) Cash flow from financing activities: Proceeds from investment by member 490,916 — — — 490,916 Capital issuance costs (12,539 ) — — — (12,539 ) Net proceeds from debt issuance 1,415,750 — — — 1,415,750 Loans received from and payments made on loans from other Summit Companies (1,031,576 ) 1,047,015 (9,000 ) (6,439 ) — Payments on long-term debt (669,123 ) (583,340 ) — 1,056 (1,251,407 ) Payments on acquisition-related liabilities (166 ) (14,852 ) — — (15,018 ) Financing costs (10,911 ) — — — (10,911 ) Distributions from partnership (39,952 ) — — — (39,952 ) Other — — — — — Net cash provided by (used for) financing activities 142,399 448,823 (9,000 ) (5,383 ) 576,839 Net increase (decrease) in cash (1,848 ) 328 (663 ) (5,550 ) (7,733 ) Cash — Beginning of period 10,837 697 8,793 (7,112 ) 13,215 Cash— End of period $ 8,989 $ 1,025 $ 8,130 $ (12,662 ) $ 5,482 Condensed Consolidating Statements of Cash Flows For the nine months ended September 27, 2014 Issuers Non- Wholly- Wholly- Non- Elim- Consol- Net cash used in operating activities $ (36,504 ) $ (2,408 ) $ 28,727 $ 668 $ (1,319 ) $ (10,836 ) Cash flow from investing activities: Acquisitions, net of cash acquired (181,754 ) — (170,187 ) — — (351,941 ) Purchase of property, plant and equipment (3,674 ) (13,472 ) (46,575 ) (523 ) — (64,244 ) Proceeds from the sale of property, plant, and equipment — — 9,345 230 — 9,575 Other — — (409 ) — 1,166 757 Net cash (used for) provided by investing activities (185,428 ) (13,472 ) (207,826 ) (293 ) 1,166 (405,853 ) Cash flow from financing activities: Proceeds from investment by member 24,350 — — 1,353 (1,353 ) 24,350 Net proceeds from debt issuance 657,217 — — — — 657,217 Loans received from and payments made on loans from other Summit Companies (195,590 ) 16,383 189,243 (2,113 ) (7,923 ) — Payments on long-term debt (251,062 ) (509 ) (6,766 ) — — (258,337 ) Payments on acquisition-related liabilities (1,500 ) — (4,307 ) — — (5,807 ) Financing costs (8,834 ) — — — — (8,834 ) Other (88 ) — (1,500 ) — 1,500 (88 ) Net cash provided by (used for) financing activities 224,493 15,874 176,670 (760 ) (7,776 ) 408,501 Net increase (decrease) in cash 2,561 (6 ) (2,429 ) (385 ) (7,929 ) (8,188 ) Cash — Beginning of period 10,375 9 3,442 3,631 (2,540 ) 14,917 Cash— End of period $ 12,936 $ 3 $ 1,013 $ 3,246 $ (10,469 ) $ 6,729	Condensed Consolidating Statements of Cash Flows For the year ended December 27, 2014 Issuers Non- wholly- owned Wholly- Non- Eliminations Consolidated Net cash (used in) provided by operating activities $ (40,964 ) $ 11,776 $ 102,219 $ 8,058 $ (2,000 ) $ 79,089 Cash flow from investing activities: Acquisitions, net of cash acquired (181,754 ) — (216,100 ) — — (397,854 ) Purchase of property, plant and equipment (4,534 ) (14,941 ) (55,222 ) (1,465 ) — (76,162 ) Proceeds from the sale of property, plant, and equipment — — 13,134 232 — 13,366 Other — (1,387 ) (597 ) — 1,354 (630 ) Net cash used for investing activities (186,288 ) (16,328 ) (258,785 ) (1,233 ) 1,354 (461,280 ) Cash flow from financing activities: Proceeds from investment by member 27,617 — — 1,354 (1,354 ) 27,617 Net proceeds from debt issuance 762,250 — — — — 762,250 Loans received from and payments made on loans from other Summit Companies (170,915 ) 5,338 173,166 (3,017 ) (4,572 ) — Payments on long-term debt (380,065 ) (793 ) (8,412 ) — — (389,270 ) Payments on acquisition-related liabilities (2,000 ) — (8,935 ) — — (10,935 ) Financing costs (9,085 ) — — — — (9,085 ) Other (88 ) — (2,000 ) — 2,000 (88 ) Net cash provided by (used for) financing activities 227,714 4,545 153,819 (1,663 ) (3,926 ) 380,489 Net increase (decrease) in cash 462 (7 ) (2,747 ) 5,162 (4,572 ) (1,702 ) Cash—Beginning of period 10,375 9 3,442 3,631 (2,540 ) 14,917 Cash—End of period $ 10,837 $ 2 $ 695 $ 8,793 $ (7,112 ) $ 13,215 Condensed Consolidating Statements of Cash Flows For the year ended December 28, 2013 Summit Non- wholly- owned Wholly- Non- Eliminations Consolidated Net cash (used for) provided by operating activities $ (232 ) $ 9,003 $ 44,746 $ 12,895 $ — $ 66,412 Cash flow from investing activities: Acquisitions, net of cash acquired — — (61,601 ) — — (61,601 ) Purchase of property, plant and equipment (3,359 ) (24,896 ) (36,629 ) (1,115 ) — (65,999 ) Proceeds from the sale of property, plant, and equipment — 3 16,020 62 — 16,085 Net cash used for investing activities (3,359 ) (24,893 ) (82,210 ) (1,053 ) — (111,515 ) Cash flow from financing activities Net proceeds from debt issuance 234,681 — — — — 234,681 Loans received from and payments made on loans from other Summit Companies (29,121 ) 15,502 19,726 (8,891 ) 2,784 — Payments on long-term debt (188,424 ) — — — — (188,424 ) Payments on acquisition-related liabilities — — (9,801 ) — — (9,801 ) Financing costs (3,864 ) (3,864 ) Other (3 ) — — — — (3 ) Net cash provided by (used for) financing activities 13,269 15,502 9,925 (8,891 ) 2,784 32,589 Net decrease (increase) in cash 9,678 (388 ) (27,539 ) 2,951 2,784 (12,514 ) Cash—Beginning of period 697 397 30,981 680 (5,324 ) 27,431 Cash—End of period $ 10,375 $ 9 $ 3,442 $ 3,631 $ (2,540 ) $ 14,917 Condensed Consolidating Statements of Cash Flows For the year ended December 29, 2012 Summit Non- wholly- owned Wholly- Non- Eliminations Consolidated Net cash provided by operating activities $ 4,845 $ 12,806 $ 36,649 $ 8,217 $ (238 ) $ 62,279 Cash flow from investing activities: Acquisitions, net of cash acquired — — (48,757 ) — — (48,757 ) Purchase of property, plant and equipment (762 ) (12,174 ) (31,818 ) (734 ) — (45,488 ) Proceeds from the sale of property, plant, and equipment — 69 8,577 190 — 8,836 Other — — 69 — — 69 Net cash used for investing activities (762 ) (12,105 ) (71,929 ) (544 ) — (85,340 ) Cash flow from financing activities Net proceeds from debt issuance 726,459 (17 ) — — — 726,442 Loans received from and payments made on loans from other Summit Companies (25,371 ) (295 ) 39,783 (8,793 ) (5,324 ) — Payments on long-term debt (697,438 ) — — — — (697,438 ) Payments on acquisition-related liabilities — — (7,519 ) — — (7,519 ) Financing costs (13,081 ) — — — — (13,081 ) Other (656 ) — — (284 ) 238 (702 ) Net cash (used for) provided by financing activities (10,087 ) (312 ) 32,264 (9,077 ) (5,086 ) 7,702 Net decrease (increase) in cash (6,004 ) 389 (3,016 ) (1,404 ) (5,324 ) (15,359 ) Cash—Beginning of period 6,701 8 33,997 2,084 — 42,790 Cash—End of period $ 697 $ 397 $ 30,981 $ 680 $ (5,324 ) $ 27,431

Supplementary Data (Unaudited)

Supplementary Data (Unaudited) (Tables)	12 Months Ended
	Dec. 27, 2014
Quarterly Financial Information Disclosure [Abstract]
Supplemental Financial Information	Supplemental financial information (unaudited) by quarter is as follows for the years ended December 27, 2014 and December 28, 2013: 2014 2013 4Q 3Q 2Q 1Q 4Q 3Q 2Q 1Q Revenue $ 334,086 $ 394,759 $ 324,295 $ 151,091 $ 238,267 $ 316,263 $ 254,842 $ 106,829 Operating income (loss) 23,307 47,749 33,922 (35,019 ) (57,742 ) 37,895 13,731 (41,861 ) Income (loss) from continuing operations 4,753 28,110 13,832 (53,048 ) (70,191 ) 22,950 244 (56,154 ) Loss (income) from discontinued operations 285 (7 ) (369 ) 20 271 160 (26 ) 123 Net income (loss) 4,468 28,117 14,201 (53,068 ) $ (70,462 ) $ 22,790 $ 270 $ (56,277 )

Summary of Organization and S54

Summary of Organization and Significant Accounting Policies - Additional Information (Detail)	Aug. 11, 2015USD ($)$ / sharesshares	Oct. 03, 2014USD ($)	Jan. 17, 2014USD ($)	Sep. 26, 2015USD ($)Customer$ / sharesshares	Sep. 27, 2014USD ($)Customer	Sep. 26, 2015USD ($)CustomerSegmentState$ / sharesshares	Sep. 27, 2014USD ($)Customer	Dec. 27, 2014USD ($)CustomerSegmentStateshares	Dec. 28, 2013USD ($)Customer	Dec. 29, 2012USD ($)Customer	Jan. 31, 2012USD ($)	May. 31, 2010
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Number of operating states | State						18		17
Number of operating segments | Segment						3		3
Number of customers accounted for more than 10% of total revenue | Customer				0	0	0	0	0	0	0
Net (gain) loss from asset dispositions						$ 4,990,000	$ 219,000	$ (6,500,000)	$ (12,419,000)	$ (2,564,000)
Impairment charges								$ 0	0	0
Inflation rate								2.50%
Amortization expense								$ 900,000	800,000	600,000
Increase in contingent consideration liability		$ 1,900,000	$ 4,500,000
Reductions recognized in contingent consideration				$ 0	$ 0	0	0	500,000	400,000
Carrying value of long-term debt				1,156,193,000		$ 1,156,193,000		$ 1,064,917,000	662,987,000
Date of incorporation						Sep. 23, 2014
Class A common shares | shares								28,571,429
Senior notes, redemption date								May 31, 2016
Interest rate derivatives				200,000,000		$ 200,000,000
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		$ 15,000,000
Annual installments amount of non-interest bearing notes payable						2,500,000		2,500,000
Decrease in other assets (noncurrent)						524,000	$ 675,000	(4,767,000)	1,708,000	$ (1,189,000)
10 1/2% Senior Notes, due 2020 [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Carrying value of long-term debt				$ 159,365,000		$ 159,365,000		$ 651,548,000	245,971,000
Senior notes, interest rate				10.50%		10.50%		10.50%
Debt instrument, face amount				$ 153,800,000		$ 153,800,000		$ 625,000,000	250,000,000
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] | 10 1/2% Senior Notes, due 2020 [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
Debt instrument, face amount				$ 288,200,000		$ 288,200,000
Debt Instrument, redemption premium						38,200,000
Accrued and unpaid interest				5,200,000		5,200,000
Follow On Public Offering [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Class A common shares | shares	22,425,000
Class A Common stock offering price per share | $ / shares	$ 25.75
Net proceeds from IPO	$ 555,800,000
Number of newly-issued shares purchased from Summit Holdings | shares	3,750,000
Number of shares purchased from outstanding shares of Summit Holding | shares	18,675,000
Amount of purchase price due	$ 80,000,000
Class B Units [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Redeemable noncontrolling interest percentage												30.00%
Revolving Credit Facility [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Revolving credit facility, fair value									26,000,000
Debt instrument, face amount				235,000,000		$ 235,000,000					$ 150,000,000
Level 3 [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Discount rate						11.00%		11.00%
Fair value of deferred consideration								$ 49,000,000	28,300,000
Fair value of noncompete obligations								4,400,000	4,200,000
Level 2 [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Fair value of long-term debt				1,155,557,000		$ 1,155,557,000		1,101,873,000	696,500,000
Carrying value of long-term debt				$ 1,156,193,000		$ 1,156,193,000		$ 1,064,917,000	$ 663,000,000
Customer Concentration Risk [Member] | Sales Revenue, Net [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Customer accounted revenue				10.00%	10.00%	10.00%	10.00%	10.00%	10.00%	10.00%
Accounting Standards Update (ASU) 2015-03 [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Decrease in other assets (noncurrent)				$ (8,800,000)
Decrease in long-term debt								$ (16,800,000)
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] | Initial Public Offering [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
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%		30.00%
Continental Cement Company, L.L.C. [Member] | Class B Units [Member] | Initial Public Offering [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Class B capital units purchased | shares				71,428,571		71,428,571
Ohio Valley Asphalt, LLC [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Redeemable noncontrolling interest percentage				20.00%		20.00%		20.00%
Blackstone Management Partners L.L.C. [Member] | Initial Public Offering [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Payment of termination fee to affiliates of Sponsors						$ 13,800,000
Minimum [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Ownership investment percentage								20.00%
Maximum [Member]
Summary Of Significant Accounting Policies And Recent Accounting Pronouncements [Line Items]
Ownership investment percentage								50.00%

Summary of Organization and S55

Summary of Organization and Significant Accounting Policies - Estimated Useful Lives of Assets (Detail)	12 Months Ended
	Dec. 27, 2014
Minimum [Member] | Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
Minimum [Member] | Plants, Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Minimum [Member] | Mobile Equipment and Barges [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Minimum [Member] | Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Minimum [Member] | Truck and Auto Fleet [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Minimum [Member] | Landfill Airspace and Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Minimum [Member] | Property, Plant and Equipment, Other Types [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	2 years
Maximum [Member] | Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years
Maximum [Member] | Plants, Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years
Maximum [Member] | Mobile Equipment and Barges [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Maximum [Member] | Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	6 years
Maximum [Member] | Truck and Auto Fleet [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Maximum [Member] | Landfill Airspace and Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	60 years
Maximum [Member] | Property, Plant and Equipment, Other Types [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years

Summary of Organization and S56

Summary of Organization and Significant Accounting policies - Intangible Assets by Type and in Total (Detail) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		$ 20,720	$ 17,340
Accumulated Amortization	$ (4,851)	(3,073)	(2,193)
Net Carrying Amount		17,647	15,147
Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		10,357	10,430
Accumulated Amortization		(2,031)	(1,604)
Net Carrying Amount		8,326	8,826
Reserve Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		9,094	5,890
Accumulated Amortization		(540)	(221)
Net Carrying Amount		8,554	5,669
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		1,020	1,020
Accumulated Amortization		(470)	(368)
Net Carrying Amount		550	$ 652
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		249
Accumulated Amortization		(32)
Net Carrying Amount		$ 217

Summary of Organization and S57

Summary of Organization and Significant Accounting Policies - Estimated Amortization Expense for Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Accounting Policies [Abstract]
2,015		$ 3,105
2,016		1,675
2,017		956
2,018		956
2,019		956
Thereafter		9,999
Total	$ 15,481	$ 17,647	$ 15,147

Summary of Organization and S58

Summary of Organization and Significant Accounting Policies - Schedule of Contingent Consideration Obligations Measured at Fair Value (Detail) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration	$ 4,559	$ 2,375
Cash flow hedge	114
Contingent consideration	2,711	$ 5,379	$ 1,908
Cash flow hedge	$ 897

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) - USD ($)	Sep. 26, 2015	Jul. 17, 2015	Sep. 26, 2015	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012	Jan. 17, 2014
Business Acquisition [Line Items]
Proforma effect on revenue						$ 1,326,861,000	$ 1,230,491,000	$ 1,022,535,000
Net income from the acquisition						$ 8,181,000	(104,705,000)	(46,405,000)
West Region [Member] | Senior Notes [Member]
Business Acquisition [Line Items]
Debt instrument, face amount									$ 260,000,000
Interest rate									10.50%
2014 Acquisitions [Member] | West Region [Member]
Business Acquisition [Line Items]
Business acquisition date						Mar. 31, 2014
2014 Acquisitions [Member] | Central Region [Member]
Business Acquisition [Line Items]
Business acquisition date						Oct. 3, 2014
2014 Acquisitions [Member] | West Region [Member]
Business Acquisition [Line Items]
Business acquisition date						Jan. 17, 2014
2014 Acquisitions [Member] | West Region [Member]
Business Acquisition [Line Items]
Business acquisition date						Sep. 30, 2014
2014 Acquisitions [Member] | East Region [Member]
Business Acquisition [Line Items]
Business acquisition date						Jun. 9, 2014
2014 Acquisitions [Member]
Business Acquisition [Line Items]
Proforma effect on revenue							305,700,000	82,400,000
Net income from the acquisition							33,700,000	4,700,000
2014 Acquisitions [Member] | West Region [Member]
Business Acquisition [Line Items]
Business acquisition date						Sep. 19, 2014
2014 Acquisitions [Member] | West Region [Member]
Business Acquisition [Line Items]
Business acquisition date						Sep. 4, 2014
2014 Acquisitions [Member] | West Region [Member] | Senior Notes [Member]
Business Acquisition [Line Items]
Debt instrument, face amount						$ 115,000,000
Interest rate						10.50%
2014 Acquisitions [Member] | West Region [Member]
Business Acquisition [Line Items]
Business acquisition date						Jul. 29, 2014
2013 Acquisitions [Member]
Business Acquisition [Line Items]
Proforma effect on revenue							8,600,000	13,800,000
Net income from the acquisition							$ (3,400,000)	$ (500,000)
2013 Acquisitions [Member] | West Region [Member]
Business Acquisition [Line Items]
Business acquisition date					Apr. 1, 2013
2013 Acquisitions [Member] | Central Region [Member]
Business Acquisition [Line Items]
Business acquisition date						Apr. 1, 2013
2012 Acquisitions [Member]
Business Acquisition [Line Items]
Proforma effect on revenue						$ 197,500,000
Net income from the acquisition						35,600,000
2012 Acquisitions [Member] | Alleyton, Southwest Ready Mix [Member]
Business Acquisition [Line Items]
Proforma effect on revenue						150,900,000
2012 Acquisitions [Member] | Colorado County S&G [Member]
Business Acquisition [Line Items]
Net income from the acquisition						$ 32,600,000
2012 Acquisitions [Member] | West Region [Member]
Business Acquisition [Line Items]
Business acquisition date						Nov. 30, 2012
2012 Acquisitions [Member] | East Region [Member]
Business Acquisition [Line Items]
Business acquisition date						Oct. 5, 2012
2012 Acquisitions [Member] | Central Region [Member]
Business Acquisition [Line Items]
Business acquisition date						Feb. 29, 2012
Davenport Acquisition [Member]
Business Acquisition [Line Items]
Proforma effect on revenue			$ 477,706,000	$ 1,069,305,000
Net income from the acquisition			$ 67,229,000	24,506,000
Net cash paid for acquisitions	$ 448,710,000	$ 450,000,000
Pro forma adjustment, reduction of transaction costs				6,500,000
Pro forma adjustment, additional depreciation, depletion, amortization and accretion				$ 7,500,000

Acquisitions - Summary of Profo

Acquisitions - Summary of Proforma Information (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Acquisition Date [Line Items]
Revenue			$ 1,326,861	$ 1,230,491	$ 1,022,535
Net income			$ 8,181	$ (104,705)	$ (46,405)
Davenport Acquisition [Member]
Acquisition Date [Line Items]
Revenue	$ 477,706	$ 1,069,305
Net income	$ 67,229	$ 24,506

Acquisitions - Summary of Asset

Acquisitions - Summary of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Sep. 26, 2015	Jul. 17, 2015	Jan. 17, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Business Acquisition [Line Items]
Goodwill	$ 567,836			$ 419,270	$ 127,038	$ 179,120
Davenport Acquisition [Member]
Business Acquisition [Line Items]
Inventories	21,538
Property, plant and equipment	272,815
Other assets	6,537
Financial liabilities	(1,509)
Other long-term liabilities	(95)
Net assets acquired	299,286
Goodwill	150,710
Purchase price	449,996
Net cash paid for acquisitions	448,710	$ 450,000
Transfer of assets	(2,182)
Working capital true-up	$ 896
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Financial assets			$ 15,489	22,101	8,302	1,397
Inventories			2,548	8,249	3,954	6,988
Property, plant and equipment			47,985	74,687	40,580	21,543
Intangible assets				3,398	7,428	3,172
Other assets			2,595	3,337	52	1,330
Financial liabilities			(10,054)	(17,610)	(6,164)	(944)
Other long-term liabilities			(990)	(11,727)	(1,050)	(364)
Net assets acquired			57,573	82,435	53,102	33,122
Goodwill			147,064	148,838	16,120	26,230
Purchase price			204,637	231,273	69,222	59,352
Acquisition related liabilities			(22,123)	(10,656)	(7,902)	(10,547)
Other			(2,087)	(3,190)	281	(48)
Net cash paid for acquisitions			$ 180,427	$ 217,427	$ 61,601	$ 48,757

Acquisitions - Summary of Ass62

Acquisitions - Summary of Assets Acquired and Liabilities Assumed (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Business Acquisition [Line Items]
Acquired intangible assets weighted average life	18 years
Aggregate reserves	$ 5.9
Reserve Rights [Member]
Business Acquisition [Line Items]
Acquired intangible assets weighted average life		20 years
Leases [Member]
Business Acquisition [Line Items]
Acquired intangible assets weighted average life			11 years

Goodwill - Additional Informati

Goodwill - Additional Information (Detail)	Dec. 29, 2014Unit	Dec. 27, 2014USD ($)	Dec. 28, 2013USD ($)	Dec. 29, 2012USD ($)
Goodwill [Line Items]
Reporting unit percentage of fair value less than carrying amount		50.00%
Weightage for DCF valuation and market assessment to estimate fair value of operating unit			50.00%
Goodwill impairment			$ 68,202,000
Impairment charges recognized		$ 0	$ 0	$ 0
Subsequent Event [Member]
Goodwill [Line Items]
Total number of reporting units | Unit	11
Goodwill [Member]
Goodwill [Line Items]
Discount rate			11.00%

Goodwill - Summary of Recogniti

Goodwill - Summary of Recognition of the Goodwill Impairment Charges (Detail) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Goodwill:
East region	$ 567,836	$ 419,270	$ 127,038	$ 179,120
Utah Operations in the West Region [Member]
Goodwill:
East region			$ 36,589

Goodwill - Summary of Changes i

Goodwill - Summary of Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Goodwill [Line Items]
Beginning balance	$ 419,270	$ 127,038	$ 179,120
Acquisitions	155,508	295,902	16,120
Foreign currency translation adjustments	(6,942)	(3,670)
Impairment			(68,202)
Ending balance	567,836	419,270	127,038
West Region [Member]
Goodwill [Line Items]
Beginning balance	297,085	54,249	91,393
Acquisitions	4,579	246,506	16,120
Foreign currency translation adjustments	(6,942)	(3,670)
Impairment			(53,264)
Ending balance	294,722	297,085	54,249
Central Region [Member]
Goodwill [Line Items]
Beginning balance	96,025	72,789	72,789
Acquisitions	150,929	23,236
Ending balance	246,954	96,025	72,789
East Region [Member]
Goodwill [Line Items]
Beginning balance	26,160		14,938
Acquisitions	0	26,160
Impairment			$ (14,938)
Ending balance	$ 26,160	$ 26,160

Discontinued Operations - Addit

Discontinued Operations - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 29, 2012USD ($)
Discontinued Operations and Disposal Groups [Abstract]
Sale of railroad construction, repair business and environmental business	$ 3.1

Discontinued Operations - Reven

Discontinued Operations - Revenue and Loss before Income Tax Expense from Discontinued Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Discontinued Operations and Disposal Groups [Abstract]
Total revenue	$ 1,260	$ 3,884	$ 50,152
(Income) loss from discontinued operations before income taxes	$ (71)	$ 528	$ 3,546

Accounts Receivable, Net - Summ

Accounts Receivable, Net - Summary of Accounts Receivable, Net (Detail) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade accounts receivable	$ 194,235	$ 131,060	$ 85,188
Retention receivables	13,396	12,053	15,966
Receivables from related parties	705	333	202
Accounts receivable	208,336	143,446	101,356
Less: Allowance for doubtful accounts	(2,397)	(2,144)	(2,019)
Accounts receivable, net	$ 205,939	$ 141,302	$ 99,337

Inventories - Components of Inv

Inventories - Components of Inventories (Detail) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Inventory [Line Items]
Aggregate stockpiles	$ 90,776	$ 88,211	$ 70,300
Finished goods	11,284	8,826	11,207
Work in process	6,511	1,801	2,623
Raw materials	29,465	12,715	12,302
Total	$ 138,036	$ 111,553	$ 96,432

Property, Plant and Equipment70

Property, Plant and Equipment, Net - Components of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		$ 1,229,976	$ 1,044,160
Less accumulated depreciation, depletion and amortization	$ (343,087)	(279,375)	(212,382)
Property, plant and equipment, net	$ 1,276,227	950,601	831,778
Land (Mineral Bearing) and Asset Retirement Costs [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		129,957	107,007
Land (Non-Mineral Bearing) [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		112,932	81,331
Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		86,702	77,535
Plants, Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		622,466	553,113
Mobile Equipment and Barges [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		182,334	117,828
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		14,087	10,001
Truck and Auto Fleet [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		22,821	19,165
Landfill Airspace and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		48,513	46,841
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		8,445	29,560
Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross		$ 1,719	$ 1,779

Property, Plant and Equipment71

Property, Plant and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012	Sep. 26, 2015
Property, Plant and Equipment [Line Items]
Depreciation, depletion and amortization expense	$ 85,800	$ 71,400	$ 68,600
Property, plant and equipment, net	950,601	831,778		$ 1,276,227
Less accumulated depreciation, depletion and amortization	279,375	212,382		$ 343,087
Future minimum rental commitments year one	18,100
Future minimum rental commitments year two	5,100
Future minimum rental commitments year three	5,300
Future minimum rental commitments year four	700
Future minimum rental commitments year five	$ 700
Building lease original term	30 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Equipment leases terms	5 years
Capital Leases for Equipment and Building [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 30,000	11,300
Less accumulated depreciation, depletion and amortization	3,600	$ 1,300
Capital leases, accrued expenses obligations	$ 17,500

Accrued Expenses - Components o

Accrued Expenses - Components of Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014		Dec. 28, 2013
Schedule Of Accrued Expenses [Line Items]
Interest	$ 12,973	$ 32,475		$ 17,294
Payroll and benefits	22,095	20,326		16,368
Capital lease obligations	16,065	17,530		2,068
Insurance	13,710	11,402		7,445
Non-income taxes	10,221	5,520		4,168
Professional fees	1,305	3,299		2,352
Other	14,511	10,944	[1]	7,556	[1]
Total	$ 90,880	$ 101,496		$ 57,251
[1]	Consists primarily of subcontractor and working capital settlement accruals.

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Detail) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Debt Instrument [Line Items]
Revolving credit facility	$ 60,000		$ 26,000
Long-term debt:
Long-term debt, total	1,156,193	$ 1,064,917	662,987
Current portion of long-term debt	8,125	5,275	4,220
Long-term debt	1,148,068	1,059,642	658,767
10 1/2% Senior Notes, due 2020 [Member]
Long-term debt:
Long-term debt, total	159,365	651,548	245,971
Term Loan, due 2022 [Member] | Credit Facility [Member]
Long-term debt:
Long-term debt, total	646,828	$ 413,369	$ 417,016
6 1/8% Senior Notes, due 2023 [Member]
Long-term debt:
Long-term debt, total	$ 350,000

Debt - Schedule of Debt (Parent

Debt - Schedule of Debt (Parenthetical) (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
10 1/2% Senior Notes, due 2020 [Member]
Debt Instrument [Line Items]
Long-term debt, face value	$ 153.8	$ 625	$ 250
Original issuance discount	$ 5.5	$ 26.5	4
Debt instrument interest rate	10.50%	10.50%
Debt instrument maturity year	Dec. 1, 2020	Dec. 1, 2020
Term Loan, due 2022 [Member] | Credit Facility [Member]
Debt Instrument [Line Items]
Long-term debt, face value	$ 650	$ 415.7	419.9
Original issuance discount	$ 3.1	$ 2.3	$ 2.9
Debt instrument maturity year	Dec. 1, 2022	Dec. 1, 2022
6 1/8% Senior Notes, due 2023 [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	6.125%
Debt instrument maturity year	Jul. 15, 2023

Debt - Schedule of Contractual

Debt - Schedule of Contractual Payments of Long-Term Debt (Detail) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Debt Disclosure [Abstract]
2015 (three months)	$ 3,250
2,015		$ 5,275
2,016	6,500	4,220
2,017	6,500	4,220
2,018	4,875	3,165
2,019	6,500	398,790
2,020	161,925
Thereafter(After five years)		625,000
Thereafter (After six years)	964,250
Total	1,153,800	1,040,670
Plus: Original issue net premium	2,393	24,247
Total debt	$ 1,156,193	$ 1,064,917	$ 662,987

Debt - Senior Notes - Additiona

Debt - Senior Notes - Additional Information (Detail) - USD ($)	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 26, 2015	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012	Aug. 31, 2015	Apr. 30, 2015	Mar. 17, 2015	Mar. 11, 2015	Sep. 08, 2014	Jan. 17, 2014	Jan. 31, 2012
Debt Instrument [Line Items]
Original issuance discount													$ 9,500,000
Proceeds from issuance of debt		$ 1,415,750,000	$ 657,217,000	$ 762,250,000	$ 234,681,000	$ 726,442,000
Premium of debt instrument	$ 2,393,000	2,393,000		24,247,000
Write off of deferred financing fees		12,135,000			3,100,000
Term Loan Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity on credit facility													422,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 235,000,000	$ 235,000,000											150,000,000
Maximum borrowing capacity on credit facility									$ 235,000,000	$ 150,000,000
6 1/8% Senior Notes, due 2023 [Member]
Debt Instrument [Line Items]
Interest rate	6.125%	6.125%
Maturity date		Jul. 15, 2023
10 1/2% Senior Notes, due 2020 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 153,800,000	$ 153,800,000		$ 625,000,000	$ 250,000,000
Interest rate	10.50%	10.50%		10.50%
Maturity date		Dec. 1, 2020		Dec. 1, 2020
10 1/2% Senior Notes, due 2020 [Member] | Initial Public Offering [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 288,200,000	$ 288,200,000
Interest rate	10.50%	10.50%
Debt Instrument, redemption premium		$ 38,200,000
Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument financing fees						$ 9,500,000
Refinance of existing senior secured term loan facility							$ 183,000,000
Senior Notes [Member] | Davenport Acquisition [Member]
Debt Instrument [Line Items]
Initial purchase price		370,000,000
Senior Notes [Member] | 6 1/8% Senior Notes, due 2023 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 350,000,000	$ 350,000,000
Interest rate	6.125%	6.125%
Maturity date		Jul. 15, 2023
Percentage of par value of senior notes		100.00%
Notes payable commencing date		Jan. 15, 2016
Senior Notes [Member] | 10 1/2% Senior Notes, due 2020 [Member]
Debt Instrument [Line Items]
Debt instrument, amount redeemed		$ 183,000,000
Charges on redemption	$ 14,100,000	45,400,000
Debt Instrument, redemption premium	18,200,000	56,400,000
Write off of deferred financing fees	2,800,000	7,500,000
Net benefit from the write-off the original issuance premium and discount	6,900,000	18,500,000
Senior Notes [Member] | 10 1/2% Senior Notes, due 2020 [Member] | Initial Public Offering [Member]
Debt Instrument [Line Items]
Debt instrument, face amount								$ 288,200,000
Summit Materials And Summit Materials Finance Corp [Member] | Senior Notes (Additional Notes) [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
Summit Materials And Summit Materials Finance Corp [Member] | Existing Secured Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount				$ 250,000,000
Summit Materials And Summit Materials Finance Corp [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount													$ 250,000,000
Interest rate													10.50%
Maturity date				Jan. 31, 2020
Summit Materials And Summit Materials Finance Corp [Member] | Senior Notes [Member] | Senior Notes (Additional Notes) [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] | Senior Notes [Member] | Existing Secured Notes [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 250,000,000	$ 250,000,000

Debt - Senior Secured Credit Fa

Debt - Senior Secured Credit Facilities - Additional Information (Detail) - USD ($)

Jul. 17, 2015

Mar. 17, 2015

Sep. 26, 2015

Sep. 27, 2014

Sep. 26, 2015

Sep. 27, 2014

Dec. 27, 2014

Dec. 28, 2013

Dec. 29, 2012

Jul. 16, 2015

Mar. 11, 2015

Jan. 31, 2012

Debt Instrument [Line Items]

Proceeds from issuance of debt

$ 1,415,750,000

$ 657,217,000

$ 762,250,000

$ 234,681,000

$ 726,442,000

Write-off of costs from extinguishment of debt

12,135,000

3,100,000

Outstanding letters of credit

$ 60,000,000

60,000,000

26,000,000

Deferred financing fees, net

17,200,000

11,500,000

Financing fees

(32,641,000)

(64,313,000)

$ (3,115,000)

$ (9,469,000)

Interest expense

17,800,000

$ 19,900,000

54,600,000

$ 56,400,000

Senior Secured Credit Facilities [Member]

Debt Instrument [Line Items]

Debt instrument, face amount

650,000,000

$ 650,000,000

$ 422,000,000

Quarterly principal repayments percentage

0.25%

0.25%

Frequency of periodic payment

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

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

Proceeds from issuance of debt

$ 25,000,000

Change in interest rate

1.00%

Maturity date

Jul. 17, 2022

Jan. 30, 2019

Credit facility revolving commitments

$ 150,000,000

Basis spread description

25 basis point

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

Debt Instrument [Line Items]

First lien leverage ratio

4.751

Senior Secured Credit Facilities [Member] | Base Rate [Member]

Debt Instrument [Line Items]

Debt instrument interest rate

2.25%

Senior Secured Credit Facilities [Member] | London Interbank Offered Rate (LIBOR) [Member]

Debt Instrument [Line Items]

Basis spread on variable rate

3.25%

Senior Secured Credit Facilities [Member] | Libor Floor Rate [Member]

Debt Instrument [Line Items]

Basis spread on variable rate

1.00%

Senior Secured Credit Facilities [Member] | Uncommitted Incremental Facility [Member]

Debt Instrument [Line Items]

Line of credit facility additional borrowing capacity

$ 135,000,000

Effective interest rate

5.00%

Senior Secured Credit Facilities [Member] | Uncommitted Incremental Facility [Member] | Federal Funds Effective Rate [Member]

Debt Instrument [Line Items]

Basis spread on variable rate

0.50%

Senior Secured Credit Facilities [Member] | Uncommitted Incremental Facility [Member] | Libor Plus Rate [Member]

Debt Instrument [Line Items]

Basis spread on variable rate

1.00%

Senior Secured Credit Facilities [Member] | Uncommitted Incremental Facility [Member] | Base Rate [Member]

Debt Instrument [Line Items]

Line of credit facility minimum interest rate

2.25%

Interest rate - Revolving credit commitments, minimum interest rate

2.75%

Senior Secured Credit Facilities [Member] | Uncommitted Incremental Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]

Debt Instrument [Line Items]

Basis spread on variable rate

3.75%

Line of credit facility minimum interest rate

1.25%

Senior Secured Credit Facilities [Member] | First Lien Leverage Ratio January 1, 2013 To June 30, 2014 [Member] | Maximum [Member]

Debt Instrument [Line Items]

First lien leverage ratio

4.75

Senior Secured Credit Facilities [Member] | First Lien Net Leverage Ratio - July 1, 2014 to June 30, 2015 [Member] | Maximum [Member]

Debt Instrument [Line Items]

First lien leverage ratio

4.50

Senior Secured Credit Facilities [Member] | First Lien Net Leverage Ratio - Thereafter [Member] | Maximum [Member]

Debt Instrument [Line Items]

First lien leverage ratio

4.25

Senior Secured Credit Facilities [Member] | Interest Coverage Ratio - January 1, 2013 to December 31, 2014 [Member] | Minimum [Member]

Debt Instrument [Line Items]

Interest coverage ratio, maximum

1.70

Senior Secured Credit Facilities [Member] | Interest Coverage Ratio - Thereafter [Member] | Minimum [Member]

Debt Instrument [Line Items]

Interest coverage ratio, maximum

1.85

Senior Secured Credit Facilities [Member] | Term Loan Facility [Member]

Debt Instrument [Line Items]

Line of credit facility, maximum borrowing capacity

$ 650,000,000

$ 422,000,000

Revolving Credit Facility [Member]

Debt Instrument [Line Items]

Debt instrument, face amount

235,000,000

$ 235,000,000

$ 150,000,000

Effective interest rate

4.20%

Revolving credit facility, maturity date

Mar. 11, 2020

Jan. 30, 2017

Outstanding letters of credit

$ 60,000,000

$ 60,000,000

$ 0

Line of credit facility, maximum borrowing capacity

$ 235,000,000

$ 150,000,000

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

Debt Instrument [Line Items]

Basis spread on variable rate

0.50%

0.50%

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

Debt Instrument [Line Items]

Basis spread on variable rate

1.00%

1.00%

Effective interest rate

3.60%

3.60%

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

Debt Instrument [Line Items]

Basis spread on variable rate

2.50%

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%

3.50%

Letter of Credit [Member]

Debt Instrument [Line Items]

Outstanding letters of credit

$ 24,400,000

$ 24,400,000

$ 23,300,000

Line of credit facility, maximum borrowing capacity

$ 150,600,000

$ 150,600,000

$ 126,700,000

Debt - Other - Additional Infor

Debt - Other - Additional Information (Detail) - Other Debt [Member] - Canada [Member] CAD in Millions	Jan. 15, 2015CAD
Revolving Credit Commitment to be Used for Operating Activities [Member] | Prime Rate [Member]
Debt Instrument [Line Items]
Prime rate	0.20%
Revolving Credit Commitment to be Used for Operating Activities [Member] | Prime Rate [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Prime rate	0.20%
Revolving Credit Commitment to be Used for Capital Equipment [Member] | Prime Rate [Member]
Debt Instrument [Line Items]
Prime rate	0.90%
Revolving Credit Commitment to be Used for Capital Equipment [Member] | Prime Rate [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Prime rate	0.90%
Revolving Credit Facility [Member] | Revolving Credit Commitment to be Used for Operating Activities [Member]
Debt Instrument [Line Items]
Revolving credit commitment	CAD 6
Revolving Credit Facility [Member] | Revolving Credit Commitment to be Used for Operating Activities [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Revolving credit commitment	6
Revolving Credit Facility [Member] | Revolving Credit Commitment to be Used for Capital Equipment [Member]
Debt Instrument [Line Items]
Revolving credit commitment	0.5
Revolving Credit Facility [Member] | Revolving Credit Commitment to be Used for Capital Equipment [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Revolving credit commitment	0.5
Revolving Credit Facility [Member] | Credit Commitment to Provide Guarantees on Behalf of Mainland [Member]
Debt Instrument [Line Items]
Revolving credit commitment	0.4
Revolving Credit Facility [Member] | Credit Commitment to Provide Guarantees on Behalf of Mainland [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Revolving credit commitment	CAD 0.4

Accumulated Other Comprehensi79

Accumulated Other Comprehensive Loss - Summary of Changes in Each Component of Accumulated Comprehensive Income Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			$ (15,546)	$ (6,045)	$ (6,045)
Postretirement adjustment				2,164	(3,919)	$ 4,407	$ (3,648)
Foreign currency translation adjustment	$ (6,296)	$ (1,764)	(11,531)	(1,764)	(5,816)
Loss on cash flow hedges	(1,010)		(1,010)
Ending Balance	(28,087)		(28,087)		(15,546)	(6,045)
Pension And Other Postretirement Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(9,730)	(6,045)	$ (6,045)	(9,130)	(6,577)
Foreign currency translation adjustment
Ending Balance	(9,730)	(5,472)	(9,730)	(5,472)	$ (9,730)	(6,045)	(9,130)
Pension And Other Postretirement Benefit Plans [Member] | Postretirement Curtailment Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Postretirement adjustment				(942)	(942)
Pension And Other Postretirement Benefit Plans [Member] | Postretirement Liability Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Postretirement adjustment				$ 1,515	$ (2,743)	$ 3,085	$ (2,553)
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(5,816)
Foreign currency translation adjustment			(11,531)	$ (1,764)	$ (5,816)
Ending Balance	(17,347)	(1,764)	(17,347)	(1,764)	$ (5,816)
Foreign Currency Translation Adjustments [Member] | Postretirement Curtailment Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Postretirement adjustment
Foreign Currency Translation Adjustments [Member] | Postretirement Liability Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Postretirement adjustment
Cash Flow Hedge Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Loss on cash flow hedges			(1,010)
Ending Balance	(1,010)		(1,010)
Accumulated Other Comprehensive Loss (AOCI) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(15,546)	(6,045)	$ (6,045)	$ (9,130)	$ (6,577)
Foreign currency translation adjustment			(11,531)	(1,764)	(5,816)
Loss on cash flow hedges			(1,010)
Ending Balance	$ (28,087)	$ (7,236)	$ (28,087)	(7,236)	(15,546)	(6,045)	(9,130)
Accumulated Other Comprehensive Loss (AOCI) [Member] | Postretirement Curtailment Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Postretirement adjustment				(942)	(942)
Accumulated Other Comprehensive Loss (AOCI) [Member] | Postretirement Liability Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Postretirement adjustment				$ 1,515	$ (2,743)	$ 3,085	$ (2,553)

Income Taxes - Components of In

Income Taxes - Components of Income Tax Benefit (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Provision for income taxes:
Current					$ (905)	$ 1,761	$ (452)
Deferred				$ (525)	(5,927)	(4,408)	(3,468)
Income tax benefit	$ (2,655)	$ (1,038)	$ (12,468)	$ (2,498)	$ (6,983)	$ (2,647)	$ (3,920)

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Tax Benefit (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Income Tax Disclosure [Abstract]
Income tax benefit at federal statutory tax rate					$ (4,643)	$ (37,160)	$ (19,074)
Less: Income tax benefit at federal statutory tax rate for LLC entities					(2,272)	32,801	16,167
State and local income taxes					(224)	130	(90)
Depletion expense					(129)	(411)	(377)
Goodwill impairment						1,046
Effective rate change					(241)		(532)
Valuation allowance					1,693	729	36
Impact of international operations					(73)
Prior year true-up adjustments and amended returns					(624)
Other					(470)	218	(50)
Income tax benefit	$ (2,655)	$ (1,038)	$ (12,468)	$ (2,498)	$ (6,983)	$ (2,647)	$ (3,920)

Income Taxes - Components of Ne

Income Taxes - Components of Net Deferred Income Tax Liability (Detail) - USD ($) $ in Thousands	Dec. 27, 2014	Dec. 28, 2013
Deferred tax (liabilities) assets:
Accelerated depreciation	$ (40,141)	$ (33,146)
Mining reclamation reserve	2,180	1,502
Net operating loss	7,106	2,227
Capital losses on securities		997
Net intangible assets	(1,072)	(607)
Inventory purchase accounting adjustments	1,275	1,288
Working capital (e.g., accrued compensation, prepaid assets)	(10)	1,655
Deferred tax liabilities, net	(30,662)	(26,084)
Less valuation allowance on loss carryforwards	(2,523)	(1,826)
Total	(33,185)	(27,910)
Other current assets	1,167	2,316
Other noncurrent liabilities	(34,352)	(30,226)
Total	$ (33,185)	$ (27,910)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Income Taxes [Line Items]
Liabilities for uncertain tax positions	$ 0		$ 0		$ 0
Income tax expense or benefit recognized in other comprehensive loss					0	$ 0	$ 0
Interest and penalties recognized in income tax expense	0	$ 0	0	$ 0
Total dividend distribution	23,500,000		39,900,000
Distributions paid in cash to Summit Holdings' partners	14,600,000		39,952,000
Distributions paid in cash to Summit Inc.	$ 8,900,000		13,500,000
Scenario, Previously Reported [Member]
Income Taxes [Line Items]
Distributions paid in cash to Summit Holdings' partners			$ 26,400,000
Federal [Member]
Income Taxes [Line Items]
Net operating loss carryforwards					18,900,000
State and Local Jurisdiction [Member]
Income Taxes [Line Items]
Net operating loss carryforwards					$ 800,000
Federal and State Jurisdiction [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiry year					2,033
Minimum [Member]
Income Taxes [Line Items]
Tax years open subject to audit					2,011
Maximum [Member]
Income Taxes [Line Items]
Tax years open subject to audit					2,014

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Detail)	12 Months Ended
	Dec. 26, 2015USD ($)	Dec. 27, 2014USD ($)Pension_Plan	Dec. 28, 2013USD ($)	Dec. 29, 2012USD ($)
Defined Benefit Plan Disclosure [Line Items]
Expense for defined contribution plans		$ 3,800,000	$ 2,300,000	$ 2,200,000
Number of noncontributory defined benefit pension plans | Pension_Plan		2
Effective date of plan amended to eliminate		Jan. 1, 2014
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of investments		$ 0	$ 0
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation		30.00%
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation		63.00%
Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation		5.00%
Precious Metals [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation		2.00%
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Assumed health care cost trend rates		6.00%	7.00%
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Assumed health care cost trend rates		8.00%	9.00%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss expected to be amortized from AOCI		$ 300,000
Pension Benefits [Member] | Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to plans	$ 1,100,000
Healthcare & Life Ins [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss expected to be amortized from AOCI		$ 100,000
Healthcare & Life Ins [Member] | Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to plans	$ 1,000,000

Employee Benefit Plans - Obliga

Employee Benefit Plans - Obligations and Funded Status (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Pension Benefits [Member]
Change in benefit obligations:
Beginning of period	$ 25,644	$ 28,674
Service cost	75	295	$ 276
Interest cost	1,081	963	1,055
Actuarial loss (gain)	3,798	(2,674)
Benefits paid	(1,689)	(1,614)
End of period	28,909	25,644	28,674
Change in fair value of plan assets:
Beginning of period	19,074	17,863
Actual return on plan assets	526	1,512
Employer contributions	961	1,313
Benefits paid	(1,689)	(1,614)
End of period	18,872	19,074	17,863
Funded status of plans	(10,037)	(6,570)
Noncurrent liabilities	(10,037)	(6,570)
Liability recognized	(10,037)	(6,570)
Amounts recognized in accumulated other comprehensive loss:
Net actuarial loss	9,365	4,831
Total amount recognized	9,365	4,831
Healthcare & Life Ins [Member]
Change in benefit obligations:
Beginning of period	14,155	15,810
Service cost	106	236	207
Interest cost	493	513	585
Actuarial loss (gain)	1,992	(1,048)
Special termination benefits		39
Change in plan provision	(2,553)
Benefits paid	(837)	(1,395)
End of period	13,356	14,155	$ 15,810
Change in fair value of plan assets:
Employer contributions	837	1,395
Benefits paid	(837)	(1,395)
Funded status of plans	(13,356)	(14,155)
Current liabilities	(1,041)	(1,268)
Noncurrent liabilities	(12,315)	(12,887)
Liability recognized	(13,356)	(14,155)
Amounts recognized in accumulated other comprehensive loss:
Net actuarial loss	5,904	4,139
Prior service cost	(2,380)	(1,346)
Total amount recognized	$ 3,524	$ 2,793

Employee Benefit Plans - Amount

Employee Benefit Plans - Amounts Recognized in Other Comprehensive (Gain) Loss (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Amounts recognized in other comprehensive loss (income):
Total amount recognized	$ (2,164)	$ 3,919	$ (4,407)	$ 3,648
Pension Benefits [Member]
Amounts recognized in other comprehensive loss (income):
Net actuarial gain (loss)		4,650	(2,838)	2,444
Amortization of gain		(117)	(387)	(261)
Total amount recognized		4,533	(3,225)	2,183
Healthcare & Life Ins [Member]
Amounts recognized in other comprehensive loss (income):
Net actuarial gain (loss)		1,992	(1,048)	1,597
Prior service cost		(2,553)
Amortization of prior year service cost		174	180	180
Curtailment benefit		1,346
Amortization of gain		(227)	(314)	(312)
Total amount recognized		$ 732	$ (1,182)	$ 1,465

Employee Benefit Plans - Compon

Employee Benefit Plans - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Pension Benefits [Member]
Components of net periodic benefit cost:
Service cost	$ 75	$ 295	$ 276
Interest cost	1,081	963	1,055
Amortization of loss	117	387	261
Expected return on plan assets	(1,378)	(1,348)	(1,300)
Net periodic benefit cost	(105)	297	292
Healthcare & Life Ins [Member]
Components of net periodic benefit cost:
Service cost	106	236	207
Interest cost	493	513	585
Amortization of loss	227	314	312
Expected return on plan assets			(180)
Curtailment benefit	(1,346)
Special termination benefits		39
Amortization of prior service credit	(174)	(180)
Net periodic benefit cost	$ (694)	$ 922	$ 924

Employee Benefit Plans - Weight

Employee Benefit Plans - Weighted-Average Assumptions Used to Determine Benefit Obligations (Detail)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets	7.30%	7.50%	7.50%
Pension Benefits [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.50%	4.21%
Pension Benefits [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.65%	4.46%
Healthcare & Life Ins [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.52%	4.33%

Employee Benefit Plans - Weig89

Employee Benefit Plans - Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost (Detail)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets	7.30%	7.50%	7.50%
Pension Benefits [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.21%	3.30%	3.89%
Pension Benefits [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.46%	3.57%	4.07%
Healthcare & Life Ins [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.33%	3.41%	4.00%

Employee Benefit Plans - Effect

Employee Benefit Plans - Effects of One Percentage-Point Change in Assumed Health Care Cost Trend Rates (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013
Compensation and Retirement Disclosure [Abstract]
Total service cost and interest cost components, Increase	$ 39	$ 66
APBO, Increase	1,333	1,251
Total service cost and interest cost components, Decrease	(34)	(55)
APBO, Decrease	$ (1,136)	$ (1,073)

Employee Benefit Plans - Fair V

Employee Benefit Plans - Fair Value of Company's Pension Plans' Assets (Detail) - Pension Benefits [Member] - USD ($) $ in Thousands	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	$ 18,872	$ 19,074	$ 17,863
Fixed Income Securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	18,872
Fixed Income Securities [Member] | Intermediate - Government [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	1,468	1,647
Fixed Income Securities [Member] | Intermediate - Corporate [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	3,342	3,138
Fixed Income Securities [Member] | Short Term - Government [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	2,435	2,168
Fixed Income Securities [Member] | Short Term - Corporate [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	3,700	4,040
Equity Securities [Member] | U.S. Large Cap Value [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	1,180	1,221
Equity Securities [Member] | U.S. Large Cap Growth [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	1,173	1,536
Equity Securities [Member] | U.S. Mid Cap Value [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	590	600
Equity Securities [Member] | U.S. Mid Cap Growth [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	598	603
Equity Securities [Member] | U.S. Small Cap Value [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	597	610
Equity Securities [Member] | U.S. Small Cap Growth [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	611	599
Equity Securities [Member] | International [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	1,098	889
Cash [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	1,712	1,665
Precious Metals [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	368	358
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value		8,081
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed Income Securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	7,927
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities [Member] | U.S. Large Cap Value [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	1,180	1,221
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities [Member] | U.S. Large Cap Growth [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	1,173	1,536
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities [Member] | U.S. Mid Cap Value [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	590	600
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities [Member] | U.S. Mid Cap Growth [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	598	603
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities [Member] | U.S. Small Cap Value [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	597	610
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities [Member] | U.S. Small Cap Growth [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	611	599
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities [Member] | International [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	1,098	889
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	1,712	1,665
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Precious Metals [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	368	358
Level 2 [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value		10,993
Level 2 [Member] | Fixed Income Securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	10,945
Level 2 [Member] | Fixed Income Securities [Member] | Intermediate - Government [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	1,468	1,647
Level 2 [Member] | Fixed Income Securities [Member] | Intermediate - Corporate [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	3,342	3,138
Level 2 [Member] | Fixed Income Securities [Member] | Short Term - Government [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	2,435	2,168
Level 2 [Member] | Fixed Income Securities [Member] | Short Term - Corporate [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total fair value	$ 3,700	$ 4,040

Employee Benefit Plans - Estima

Employee Benefit Plans - Estimated Benefit Payments (Detail) $ in Thousands	Dec. 27, 2014USD ($)
Pension Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
2,015	$ 1,715
2,016	1,743
2,017	1,740
2,018	1,773
2,019	1,777
2020 - 2024	8,524
Total	17,272
Healthcare & Life Ins [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
2,015	1,041
2,016	1,015
2,017	893
2,018	893
2,019	823
2020 - 2024	3,912
Total	$ 8,577

Accrued Mining and Landfill R93

Accrued Mining and Landfill Reclamation - Additional Information (Detail) - USD ($) $ in Millions	Dec. 27, 2014	Dec. 28, 2013
Asset Retirement Obligation Disclosure [Abstract]
Current portion of liabilities	$ 1.6	$ 0.5

Accrued Mining and Landfill R94

Accrued Mining and Landfill Reclamation - Activity for Asset Retirement Obligations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013
Asset Retirement Obligation Disclosure [Abstract]
Beginning balance	$ 15,781	$ 14,844
Acquired obligations	140	286
Change in cost estimate	2,233	721
Settlement of reclamation obligations	(1,178)	(1,201)
Additional liabilities incurred	463	414
Accretion expense	871	717
Ending balance	$ 18,310	$ 15,781

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Apr. 02, 2015	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012	Dec. 31, 2011
Loss Contingencies [Line Items]
Amount funded for loss incurred by joint venture		$ 8.8	$ 8.8		$ 4	$ 4.8
Accrual recorded in other noncurrent liabilities		4.3	4.3	$ 4.3
Recognized losses on indemnification agreement					$ 8	$ 1.9
Unapproved change orders and claims			3.9	3.2
Unapproved change orders within costs in excess of billings			0.5	0.5
Unapproved change orders within other current assets			2.2	2.7
Unapproved change orders within accounts receivable		$ 1.2	$ 1.2
Percentage of ownership interest in joint venture		40.00%
Value of damages sought	$ 29.4
Maximum [Member]
Loss Contingencies [Line Items]
Duration of commitments		1 year	1 year
Loss from Catastrophes [Member]
Loss Contingencies [Line Items]
Charge for costs to remove the barge				0.8
Charges recognized for lost product included in accrued expenses			$ 0.4	$ 0.9

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Detail)	Sep. 26, 2015USD ($)	Aug. 13, 2015USD ($)	Jul. 17, 2015USD ($)Business	Sep. 30, 2014USD ($)	Jan. 31, 2014USD ($)	Mar. 11, 2015USD ($)	Mar. 17, 2015USD ($)	Sep. 27, 2014USD ($)	Sep. 26, 2015USD ($)	Sep. 27, 2014USD ($)	Dec. 27, 2014USD ($)	Dec. 28, 2013USD ($)	Dec. 29, 2012USD ($)	Dec. 28, 2014USD ($)
Related Party Transaction [Line Items]
Transaction fees paid											$ 3,900,000
Revenue from unconsolidated affiliates												$ 600,000	$ 7,900,000
Costs incurred in connection with several transactions with unconsolidated affiliates												200,000	200,000
Accounts receivable from affiliates												400,000
Related party transactions				$ 5,750,000	$ 13,000,000
Assets sold to related party										$ 2,300,000
Davenport Acquisition [Member]
Related Party Transaction [Line Items]
Net cash paid for acquisitions	$ 448,710,000		$ 450,000,000
Blackstone Management Partners L.L.C. [Member]
Related Party Transaction [Line Items]
Management fees incurred							$ 1,000,000	$ 1,300,000		2,300,000	$ 4,400,000	2,600,000	2,100,000
Agreement date											Jul. 30, 2009
Percentage transaction fee on value of entity acquired									1.00%		1.00%
Consideration paid / received on assets acquired / disposed	1.00%								1.00%		1.00%
Transaction fees paid								600,000		2,300,000
Related party transactions				$ 13,000,000	$ 5,750,000
Consideration of Consolidated profit									Greater of $300,000 or 2.0%
Payment for services									$ 300,000
Threshold of annual consolidated profits									2.00%
Management fee agreement termination date									Mar. 17, 2015
Management fee paid as of termination									$ 13,800,000
Continental Cement Company, L.L.C. [Member]
Related Party Transaction [Line Items]
Sales to related parties						$ 1,400,000		$ 4,700,000		10,900,000	$ 14,300,000	12,700,000	$ 12,500,000
Accounts receivables due from related parties											$ 1,200,000	$ 200,000		$ 200,000
Non controlling interest owned										$ 700,000
Blackstone And Affiliates [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
Lafarge Na [Member] | Davenport Acquisition [Member]
Related Party Transaction [Line Items]
Net cash paid for acquisitions			$ 450,000,000
Purchase agreement date for assets acquired			Apr. 16, 2015
Purchase price paid	$ 370,000,000	$ 80,000,000
Lafarge Na [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

Acquisition-Related Liabiliti97

Acquisition-Related Liabilities - Additional Information (Detail)	12 Months Ended
	Dec. 27, 2014
Minimum [Member]
Business Acquisition [Line Items]
Period identified for deferred consideration due	5 years
Maximum [Member]
Business Acquisition [Line Items]
Period identified for deferred consideration due	20 years

Acquisition-Related Liabiliti98

Acquisition-Related Liabilities - Remaining Payments Due under Noncompete and Deferred Consideration Agreements (Detail) $ in Thousands	Dec. 27, 2014USD ($)
Business Combinations [Abstract]
2,015	$ 16,051
2,016	13,240
2,017	10,200
2,018	9,660
2,019	5,435
Thereafter	16,272
Total scheduled payments	70,858
Present value adjustments	(17,474)
Total noncompete obligations and deferred consideration	$ 53,384

Supplemental Cash Flow Inform99

Supplemental Cash Flow Information - Schedule of Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Cash payments:
Interest	$ 75,990	$ 59,179	$ 64,097	$ 52,001	$ 36,357
Income taxes	1,516	$ 1,345	$ 1,361	$ 457	$ 799
Non cash financing activities:
Purchase of noncontrolling interest in Continental Cement	$ (64,102)

Leasing Arrangements - Addition

Leasing Arrangements - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Leases [Abstract]
Rent expense, including short-term rentals	$ 5.5	$ 4	$ 3.5
Royalty expense recorded in cost of revenue	$ 9	$ 4.5	$ 3.9

Leasing Arrangements - Minimum

Leasing Arrangements - Minimum Contractual Commitments under Long-Term Operating Leases (Detail) $ in Thousands	Dec. 27, 2014USD ($)
Leases [Abstract]
2015, Operating Leases	$ 5,048
2016, Operating Leases	4,061
2017, Operating Leases	3,223
2018, Operating Leases	2,018
2019, Operating Leases	1,469
2015, Royalty Agreements	3,303
2016, Royalty Agreements	4,711
2017, Royalty Agreements	4,973
2018, Royalty Agreements	4,522
2019, Royalty Agreements	$ 4,265

Redeemable Noncontrolling In102

Redeemable Noncontrolling Interest - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014	May. 31, 2010
Redeemable Noncontrolling Interest [Line Items]
Anticipated redemption date of the instrument		2016-05
Redemption date of the debt instrument		May 31, 2016
Accretion redemption value		$ 65.1
Shares transferred		28,571,429
Percentage of number of outstanding shares		1.4695%
Shares transferred in connection with initial public offering		71,428,571
initial public offering, cash paid		$ 35
Initial public offering Non-interest bearing notes paid	$ 15	15
Initial public offering, cash paid installments	$ 2.5	$ 2.5
Class A Units [Member]
Redeemable Noncontrolling Interest [Line Items]
Economic interest of redeemable noncontrolling interest, approximately		70.00%
Class B Units [Member]
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interest percentage, approximately			30.00%
Continental Cement Company, L.L.C. [Member]
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interest percentage, approximately	30.00%	30.00%
Continental Cement Company, L.L.C. [Member] | Class A Units [Member]
Redeemable Noncontrolling Interest [Line Items]
Number of class units issued		100
Priority return percentage		11.00%
Allowable sharing percentage in distributions and liquidation proceeds		80.00%
Continental Cement Company, L.L.C. [Member] | Class B Units [Member]
Redeemable Noncontrolling Interest [Line Items]
Number of class units issued			100,000,000

Employee Long Term Incentive103

Employee Long Term Incentive Plan - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
The estimated fair value	$ 1,500,000
Dividend yield	0.00%
Share-based compensation expense	$ 2,200,000	$ 2,300,000	$ 2,500,000
Unrecognized compensation cost	$ 3,100,000
Weighted average remaining contractual term	1 year 8 months 12 days
Class D Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cumulative amount of units vested	$ 3,321	$ 2,531
Dividend yield
Class D Units [Member] | Time-Vesting Interests [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units vesting on first anniversary	20.00%
Units vesting monthly following the first anniversary	80.00%
Number of years required for remaining units to be vested under vesting condition	4 years
Period for non vested units for automatic forfeiture without consideration	8 years
Fair value of time-vesting units	$ 600,000	$ 1,600,000	$ 1,100,000
Weighted-average grant-date fair value	$ 1,368	$ 2,786	$ 3,761

Employee Long Term Incentive104

Employee Long Term Incentive Plan - Summary of Information for Class D Unit Interests (Detail) - Class D Units [Member] - $ / shares shares in Thousands	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Time-Vesting Interests [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units, Beginning balance	1,819
Number of units, Granted	410
Number of units, Vested	(1,070)
Number of units, Cancelled	(280)
Number of units, Ending balance	879	1,819
Weighted average grant-date fair value, Beginning balance	$ 2,929
Weighted average grant-date fair value, Granted	1,368	$ 2,786	$ 3,761
Weighted average grant-date fair value, Vested	3,553
Weighted average grant-date fair value, Cancelled	3,938
Weighted average grant-date fair value, Ending balance	$ 2,374	$ 2,929
Performance-Vesting Interests [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units, Beginning balance	4,877
Number of units, Granted	533
Number of units, Cancelled	(48)
Number of units, Ending balance	5,362	4,877
Weighted average grant-date fair value, Beginning balance	$ 2,928
Weighted average grant-date fair value, Granted	1,956
Weighted average grant-date fair value, Cancelled	1,388
Weighted average grant-date fair value, Ending balance	$ 2,845	$ 2,928

Employee Long Term Incentive105

Employee Long Term Incentive Plan - Weighted Average Assumptions Used to Estimate the Fair Value of Grants (Detail)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Class D Units
Dividend yield	0.00%
Class D Units [Member]
Class D Units
Risk-free interest rate, Minimum	0.50%
Risk-free interest rate		0.50%	1.62%
Risk-free interest rate, Maximum	0.68%
Dividend yield
Volatility	58.00%	58.00%	47.00%
Expected term		4 years
Class D Units [Member] | Minimum [Member]
Class D Units
Expected term	3 years		6 years
Class D Units [Member] | Maximum [Member]
Class D Units
Expected term	4 years		8 years

Segment Information - Additiona

Segment Information - Additional Information (Detail) - Segment	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Segment Reporting [Abstract]
Number of operating segments	3	3

Segment Information - Summary o

Segment Information - Summary of Financial Data for Company's Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 117,834		$ 72,412							$ 182,443	$ 112,901
Total revenue	471,905	$ 334,086	394,759	$ 324,295	$ 151,091	$ 238,267	$ 316,263	$ 254,842	$ 106,829	1,030,835	870,145	$ 1,204,231	$ 916,201	$ 926,254
Interest expense	20,436		22,085							61,649	62,555	86,742	56,443	58,079
Total assets	2,316,736	1,729,777				1,247,794				2,316,736		1,729,777	1,247,794	1,284,479
Depreciation, depletion, amortization and accretion	33,306		23,255							86,818	63,950	87,826	72,934	68,290
Initial public offering costs										28,296
Goodwill impairment													68,202
Loss on debt financings	32,641									64,313			3,115	9,469
Income (loss) from continuing operations before taxes	31,451		27,072							(58,633)	(13,604)	(13,336)	(105,798)	(50,951)
Total capital expenditures										69,672	64,244	76,162	65,999	45,488
West Region [Member]
Segment Reporting Information [Line Items]
Goodwill impairment													53,264
East Region [Member]
Segment Reporting Information [Line Items]
Goodwill impairment													14,938
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	2,280,801	1,703,713				1,233,451				2,280,801		1,703,713	1,233,451	1,262,721
Depreciation, depletion, amortization and accretion	32,678		22,849							85,132	62,902	86,358	72,468	68,209
Total capital expenditures										65,928	60,571	71,629	62,639	44,725
Operating Segments [Member] | Aggregates [Member]
Segment Reporting Information [Line Items]
Total revenue	86,070		68,636							218,336	160,002	229,047	159,019	146,991
Operating Segments [Member] | Cement [Member]
Segment Reporting Information [Line Items]
Total revenue	68,481		34,171							110,477	69,435	89,911	76,211	77,676
Operating Segments [Member] | Ready Mixed Concrete [Member]
Segment Reporting Information [Line Items]
Total revenue	95,481		75,429							254,878	189,198	274,970	112,878	100,941
Operating Segments [Member] | Asphalt [Member]
Segment Reporting Information [Line Items]
Total revenue	113,249		104,862							219,492	203,944	278,867	219,811	242,458
Operating Segments [Member] | Paving And Related Services [Member]
Segment Reporting Information [Line Items]
Total revenue	185,092		191,157							366,321	391,925	528,817	478,280	505,189
Operating Segments [Member] | West Region [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	59,574		39,105							110,940	71,646
Total revenue	261,742		211,302							597,484	478,432	665,716	426,195	484,922
Total assets	866,516	777,981				383,544				866,516		777,981	383,544	428,115
Depreciation, depletion, amortization and accretion	13,786		9,155							38,508	23,569	33,271	24,167	23,771
Income (loss) from continuing operations before taxes												96,133	28,607	14,429
Total capital expenditures										32,192	25,496	31,968	21,856	14,993
Operating Segments [Member] | Central Region [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	53,756		30,820							89,984	59,220
Total revenue	164,084		126,882							338,613	283,541	391,553	329,621	302,113
Total assets	1,189,565	704,134				657,421				1,189,565		704,134	657,421	610,003
Depreciation, depletion, amortization and accretion	15,778		9,710							37,198	28,061	38,793	33,808	30,215
Income (loss) from continuing operations before taxes												83,912	72,918	65,767
Total capital expenditures										24,335	28,485	32,114	33,030	20,996
Operating Segments [Member] | East Region [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	13,383		11,868							15,096	10,462
Total revenue	46,079		56,575							94,738	108,172	146,962	160,385	139,219
Total assets	224,720	221,598				192,486				224,720		221,598	192,486	224,603
Depreciation, depletion, amortization and accretion	3,114		3,984							9,426	11,272	14,294	14,493	14,223
Income (loss) from continuing operations before taxes												17,955	15,134	10,782
Total capital expenditures										9,401	6,590	7,547	7,753	8,736
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	(8,879)		(9,381)							(33,577)	(28,427)
Total assets	35,935	$ 26,064				$ 14,343				35,935		26,064	14,343	21,758
Depreciation, depletion, amortization and accretion	628		406							1,686	1,048	1,468	466	81
Income (loss) from continuing operations before taxes												(36,768)	(24,878)	(15,560)
Total capital expenditures										3,744	3,673	4,533	3,360	763
Operating Segment and Corporate and Other [Member]
Segment Reporting Information [Line Items]
Income (loss) from continuing operations before taxes												161,232	91,781	75,418
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Interest expense												86,742	56,443	58,079
Depreciation, depletion, amortization and accretion												87,826	72,934	68,290
Goodwill impairment													68,202
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenue	$ (76,468)		$ (79,496)							$ (138,669)	$ (144,359)	$ (197,381)	$ (129,998)	$ (147,001)

Guarantor and Non-Guarantor 108

Guarantor and Non-Guarantor Financial Information - Schedule of Condensed Consolidating Balance Sheets (Detail) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014	Sep. 27, 2014	Dec. 28, 2013	Dec. 29, 2012	Dec. 31, 2011
Current assets:
Cash	$ 5,482	$ 13,215	$ 6,729	$ 14,917	$ 27,431	$ 42,790
Cash and cash equivalents	5,482	13,215		14,917
Accounts receivable, net	205,939	141,302		99,337
Cost and estimated earnings in excess of billings	34,175	10,174		10,767
Inventories	138,036	111,553		96,432
Other current assets	21,762	17,172		13,181
Total current assets	405,394	293,416		234,634
Property, plant and equipment, net	1,276,227	950,601		831,778
Goodwill	567,836	419,270		127,038	179,120
Intangible assets, net	15,481	17,647		15,147
Other assets	51,798	48,843		39,197
Total assets	2,316,736	1,729,777		1,247,794	1,284,479
Current liabilities:
Current portion of debt	68,125	5,275		30,220
Current portion of acquisition-related liabilities	17,691	18,402		10,635
Accounts payable	113,226	78,854		72,104
Accrued expenses	90,880	101,496		57,251
Billings in excess of costs and estimated earnings	11,005	8,958		9,263
Total current liabilities	300,927	212,985		179,473
Long-term debt	1,148,068	1,059,642		658,767
Acquisition-related liabilities	33,320	42,736		23,756
Other noncurrent liabilities	114,575	93,691		77,480
Total liabilities	1,596,890	1,409,054		939,476
Redeemable noncontrolling interest		33,740		24,767
Total stockholders' equity/partners' interest	719,846	286,983		283,551
Total liabilities, redeemable noncontrolling interest and member's interest	2,316,736	1,729,777		1,247,794
Consolidation, Eliminations [Member]
Current assets:
Cash	(12,662)	(7,112)	(10,469)	(2,540)	(5,324)
Cash and cash equivalents	(12,662)	(7,112)
Accounts receivable, net	(344)	(1,233)		(1,452)
Intercompany receivables	(1,345,915)	(415,030)		(72,354)
Other current assets		(1,853)
Total current assets	(1,358,921)	(425,228)		(76,346)
Other assets	(963,928)	(1,256,418)		(314,108)
Total assets	(2,322,849)	(1,681,646)		(390,454)
Current liabilities:
Current portion of debt		(5,263)
Accounts payable	(344)	(1,233)		(1,452)
Accrued expenses	(12,662)	(8,965)		(2,540)
Intercompany payables	(1,345,915)	(415,030)		(72,354)
Total current liabilities	(1,358,921)	(430,491)		(76,346)
Long-term debt	(61,377)	(633,917)
Other noncurrent liabilities	(55,107)	(55,107)
Total liabilities	(1,475,405)	(1,119,515)		(76,346)
Redeemable noncontrolling interest		33,740		24,767
Redeemable members' interest		(34,543)		(23,450)
Total stockholders' equity/partners' interest	(847,444)	(561,328)		(315,425)
Total liabilities, redeemable noncontrolling interest and member's interest	(2,322,849)	(1,681,646)		(390,454)
Issuers [Member]
Current assets:
Cash	8,989	10,837	12,936	10,375
Cash and cash equivalents	8,989	10,837
Accounts receivable, net		1
Intercompany receivables	1,322,050	376,344		38,134
Other current assets	1,088	7,148		750
Total current assets	1,332,127	394,330		49,259
Property, plant and equipment, net	9,433	7,035		3,969
Other assets	881,923	1,153,204		296,494
Total assets	2,223,483	1,554,569		349,722
Current liabilities:
Current portion of debt	68,125	5,275		26,010
Current portion of acquisition-related liabilities		166		2,000
Accounts payable	7,436	3,655		5,455
Accrued expenses	30,998	37,101		12,041
Intercompany payables	67,671	162,728
Total current liabilities	174,230	208,925		45,506
Long-term debt	1,148,068	1,059,642		19,587
Acquisition-related liabilities				85
Other noncurrent liabilities	1,558	796		959
Total liabilities	1,323,856	1,269,363		66,137
Total stockholders' equity/partners' interest	899,627	285,206		283,585
Total liabilities, redeemable noncontrolling interest and member's interest	2,223,483	1,554,569		349,722
Non-Wholly Owned Guarantors [Member]
Current assets:
Cash		2	3	9	397	8
Cash and cash equivalents		2
Accounts receivable, net		6,629		4,587
Intercompany receivables		4,095		3,433
Inventories		8,696		10,402
Other current assets		464		444
Total current assets		19,886		18,875
Property, plant and equipment, net		302,524		301,908
Goodwill		23,124		23,124
Intangible assets, net		542		642
Other assets		25,233		17,973
Total assets		371,309		362,522
Current liabilities:
Current portion of debt		1,273		1,018
Accounts payable		6,845		9,387
Accrued expenses		10,178		9,185
Intercompany payables		4,052
Total current liabilities		22,348		19,590
Long-term debt		153,318		154,590
Other noncurrent liabilities		24,787		20,306
Total liabilities		200,453		194,486
Redeemable members' interest		34,543		23,450
Total stockholders' equity/partners' interest		136,313		144,586
Total liabilities, redeemable noncontrolling interest and member's interest		371,309		362,522
Wholly Owned Guarantors [Member]
Current assets:
Cash	1,025	697	1,013	3,442	30,981	33,997
Cash and cash equivalents	1,025	695
Accounts receivable, net	195,120	124,380		93,102
Intercompany receivables	14,869	30,539		30,787
Cost and estimated earnings in excess of billings	33,447	9,819		10,539
Inventories	132,734	98,188		85,372
Other current assets	19,319	9,638		11,715
Total current assets	396,514	273,259		234,957
Property, plant and equipment, net	1,240,126	610,717		518,935
Goodwill	519,759	340,969		102,942
Intangible assets, net	14,044	14,245		14,505
Other assets	132,532	125,462		37,535
Total assets	2,302,975	1,364,652		908,874
Current liabilities:
Current portion of debt		3,990		3,192
Current portion of acquisition-related liabilities	17,691	18,236		8,635
Accounts payable	102,571	65,018		57,142
Accrued expenses	70,386	59,477		37,342
Intercompany payables	1,274,510	245,416		71,556
Billings in excess of costs and estimated earnings	10,983	8,931		8,837
Total current liabilities	1,476,141	401,068		186,704
Long-term debt	61,377	480,599		484,590
Acquisition-related liabilities	33,320	42,736		23,671
Other noncurrent liabilities	110,856	65,479		56,215
Total liabilities	1,681,694	989,882		751,180
Total stockholders' equity/partners' interest	621,281	374,770		157,694
Total liabilities, redeemable noncontrolling interest and member's interest	2,302,975	1,364,652		908,874
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash		8,793		3,631	$ 680	$ 2,084
Accounts receivable, net				3,100
Cost and estimated earnings in excess of billings				228
Inventories				658
Other current assets				272
Total current assets				7,889
Property, plant and equipment, net				6,966
Goodwill				972
Other assets				1,303
Total assets				17,130
Current liabilities:
Accounts payable				1,572
Accrued expenses				1,223
Intercompany payables				798
Billings in excess of costs and estimated earnings				426
Total current liabilities				4,019
Total liabilities				4,019
Total stockholders' equity/partners' interest				13,111
Total liabilities, redeemable noncontrolling interest and member's interest				17,130
Non Guarantor [Member]
Current assets:
Cash	8,130	8,793	$ 3,246	$ 3,631
Cash and cash equivalents	8,130	8,793
Accounts receivable, net	11,163	11,525
Intercompany receivables	8,996	4,052
Cost and estimated earnings in excess of billings	728	355
Inventories	5,302	4,669
Other current assets	1,355	1,775
Total current assets	35,674	31,169
Property, plant and equipment, net	26,668	30,325
Goodwill	48,077	55,177
Intangible assets, net	1,437	2,860
Other assets	1,271	1,362
Total assets	113,127	120,893
Current liabilities:
Accounts payable	3,563	4,569
Accrued expenses	2,158	3,705
Intercompany payables	3,734	2,834
Billings in excess of costs and estimated earnings	22	27
Total current liabilities	9,477	11,135
Other noncurrent liabilities	57,268	57,736
Total liabilities	66,745	68,871
Total stockholders' equity/partners' interest	46,382	52,022
Total liabilities, redeemable noncontrolling interest and member's interest	$ 113,127	$ 120,893

Guarantor and Non-Guarantor 109

Guarantor and Non-Guarantor Financial Information - Schedule of Condensed Consolidating Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Condensed Financial Statements, Captions [Line Items]
Revenue	$ 471,905	$ 334,086	$ 394,759	$ 324,295	$ 151,091	$ 238,267	$ 316,263	$ 254,842	$ 106,829	$ 1,030,835	$ 870,145	$ 1,204,231	$ 916,201	$ 926,254
Cost of revenue (excluding items shown separately below)	312,399		285,497							719,838	645,934	887,160	677,052	713,346
General and administrative expenses	42,843		38,258							157,528	113,609	159,286	145,990	129,203
Goodwill impairment													68,202
Depreciation, depletion, amortization and accretion	33,306		23,255							86,818	63,950	87,826	72,934	68,290
Operating (loss) income	83,357	23,307	47,749	33,922	(35,019)	(57,742)	37,895	13,731	(41,861)	66,651	46,652	69,959	(47,977)	15,415
Other (income) expense, net	31,470		(1,408)							63,635	(2,299)	(3,447)	1,378	8,287
Interest expense	20,436		22,085							61,649	62,555	86,742	56,443	58,079
(Loss) income from continuing operations before taxes	31,451		27,072							(58,633)	(13,604)	(13,336)	(105,798)	(50,951)
Income tax benefit	(2,655)		(1,038)							(12,468)	(2,498)	(6,983)	(2,647)	(3,920)
(Loss) income from continuing operations	34,106	4,753	28,110	13,832	(53,048)	(70,191)	22,950	244	(56,154)	(46,165)	(11,106)	(6,353)	(103,151)	(47,031)
Income (loss) from discontinued operations	(57)	285	(7)	(369)	20	271	160	(26)	123	(815)	(356)	(71)	528	3,546
Net (loss) income	34,163	$ 4,468	28,117	$ 14,201	$ (53,068)	$ (70,462)	$ 22,790	$ 270	$ (56,277)	(45,350)	(10,750)	(6,282)	(103,679)	(50,577)
Net income attributable to minority interest	52		1,243							(1,917)	674	2,495	3,112	1,919
Net (loss) income attributable to member of Summit Materials, LLC	34,111		26,874							(43,433)	(11,424)	(8,777)	(106,791)	(52,496)
Comprehensive (loss) income attributable to member of Summit Materials, LLC	26,805		25,110							(55,974)	(12,615)	(18,278)	(103,706)	(55,049)
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue	(4,068)		(10,823)							(28,139)	(19,692)	(27,933)	(14,389)	(13,132)
Cost of revenue (excluding items shown separately below)	(4,068)		(10,823)							(28,139)	(19,692)	(27,933)	(14,389)	(13,132)
Other (income) expense, net	86,514		46,119							111,436	40,369	71,514	(90,834)	(48,577)
Interest expense	(10,796)		(2,408)							(21,568)	(5,934)	(9,113)	(4,232)	(1,892)
(Loss) income from continuing operations before taxes	(75,718)		(43,711)							(89,868)	(34,435)	(62,401)	95,066	50,469
(Loss) income from continuing operations	(75,718)		(43,711)							(89,868)	(34,435)	(62,401)	95,066	50,469
Net (loss) income	(75,718)		(43,711)							(89,868)	(34,435)	(62,401)	95,066	50,469
Net income attributable to minority interest	52		1,243							(1,917)	674	2,495	3,112	1,919
Net (loss) income attributable to member of Summit Materials, LLC	(75,770)		(44,954)							(87,951)	(35,109)	(64,896)	91,954	48,550
Comprehensive (loss) income attributable to member of Summit Materials, LLC	(68,464)		(43,190)							(75,410)	(34,163)	(53,815)	90,632	49,645
Summit Materials LLC (Parent) [Member]
Condensed Financial Statements, Captions [Line Items]
General and administrative expenses													7,241	8
Depreciation, depletion, amortization and accretion													465	81
Operating (loss) income													(7,706)	(89)
Other (income) expense, net													99,085	52,400
(Loss) income from continuing operations before taxes													(106,791)	(52,489)
Income tax benefit														5
(Loss) income from continuing operations													(106,791)	(52,494)
Net (loss) income													(106,791)	(52,494)
Net (loss) income attributable to member of Summit Materials, LLC													(106,791)	(52,494)
Comprehensive (loss) income attributable to member of Summit Materials, LLC													(106,791)	(52,494)
Non-Wholly Owned Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue			34,171								69,435	94,402	80,759	81,516
Cost of revenue (excluding items shown separately below)			25,603								53,229	67,951	55,241	58,319
General and administrative expenses			1,651								5,225	6,763	7,673	6,235
Depreciation, depletion, amortization and accretion			3,708								10,484	14,500	11,378	10,093
Operating (loss) income			3,209								497	5,188	6,467	6,869
Other (income) expense, net			(945)								(2,303)	(14,444)	(3,737)	(2,065)
Interest expense			2,931								8,788	11,608	10,702	12,045
(Loss) income from continuing operations before taxes			1,223								(5,988)	8,024	(498)	(3,111)
(Loss) income from continuing operations			1,223								(5,988)	8,024	(498)	(3,111)
Net (loss) income			1,223								(5,988)	8,024	(498)	(3,111)
Net (loss) income attributable to member of Summit Materials, LLC			1,223								(5,988)	8,024	(498)	(3,111)
Comprehensive (loss) income attributable to member of Summit Materials, LLC			1,223								(5,170)	2,759	3,909	(6,759)
Wholly Owned Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue	454,501		348,785							980,153	776,502	1,065,590	807,921	824,796
Cost of revenue (excluding items shown separately below)	304,204		253,284							696,068	581,602	796,078	611,799	649,577
General and administrative expenses	32,362		27,418							90,959	80,938	119,250	129,768	121,633
Goodwill impairment													68,202
Depreciation, depletion, amortization and accretion	31,374		18,618							80,997	51,351	70,116	60,078	57,080
Operating (loss) income	86,561		49,465							112,129	62,611	80,146	(61,926)	(3,494)
Other (income) expense, net	3,639		(2,679)							7,140	(4,233)	(6,687)	(3,410)	6,630
Interest expense	15,286		13,416							45,332	37,831	51,248	49,591	47,293
(Loss) income from continuing operations before taxes	67,636		38,728							59,657	29,013	35,585	(108,107)	(57,417)
Income tax benefit	(2,690)		(1,038)							(12,852)	(1,071)	(5,766)	(2,647)	(3,925)
(Loss) income from continuing operations	70,326		39,766							72,509	30,084	41,351	(105,460)	(53,492)
Income (loss) from discontinued operations	(57)		(7)							(815)	(356)	(71)	528	3,546
Net (loss) income	70,383		39,773							73,324	30,440	41,422	(105,988)	(57,038)
Net (loss) income attributable to member of Summit Materials, LLC	70,383		39,773							73,324	30,440	41,422	(105,988)	(57,038)
Comprehensive (loss) income attributable to member of Summit Materials, LLC	69,373		39,773							72,314	30,440	41,422	(105,988)	(57,038)
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue	21,472											72,172	41,910	33,074
Cost of revenue (excluding items shown separately below)	12,263											51,064	24,401	18,582
General and administrative expenses	1,600											2,537	1,308	1,327
Depreciation, depletion, amortization and accretion	1,304											1,742	1,013	1,036
Operating (loss) income	6,305											16,829	15,188	12,129
Other (income) expense, net	(17)											(3)	274	(101)
Interest expense	900											1,172	382	633
(Loss) income from continuing operations before taxes	5,422											15,660	14,532	11,597
Income tax benefit	35											210
(Loss) income from continuing operations	5,387											15,450	14,532	11,597
Net (loss) income	5,387											15,450	14,532	11,597
Net (loss) income attributable to member of Summit Materials, LLC	5,387											15,450	14,532	11,597
Comprehensive (loss) income attributable to member of Summit Materials, LLC	(909)											9,634	$ 14,532	$ 11,597
Issuers [Member]
Condensed Financial Statements, Captions [Line Items]
General and administrative expenses	8,881		8,694							61,634	26,384	30,736
Depreciation, depletion, amortization and accretion	628		406							1,686	1,047	1,468
Operating (loss) income	(9,509)		(9,100)							(63,320)	(27,431)	(32,204)
Other (income) expense, net	(58,666)		(43,887)							(55,083)	(36,161)	(53,827)
Interest expense	15,046		7,913							35,196	21,581	31,827
(Loss) income from continuing operations before taxes	34,111		26,874							(43,433)	(12,851)	(10,204)
Income tax benefit											(1,427)	(1,427)
(Loss) income from continuing operations	34,111		26,874							(43,433)	(11,424)	(8,777)
Net (loss) income	34,111		26,874							(43,433)	(11,424)	(8,777)
Net (loss) income attributable to member of Summit Materials, LLC	34,111		26,874							(43,433)	(11,424)	(8,777)
Comprehensive (loss) income attributable to member of Summit Materials, LLC	$ 26,805		25,110							(55,974)	(12,615)	$ (18,278)
Non Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Revenue			22,626							78,821	43,900
Cost of revenue (excluding items shown separately below)			17,433							51,909	30,795
General and administrative expenses			495							4,935	1,062
Depreciation, depletion, amortization and accretion			523							4,135	1,068
Operating (loss) income			4,175							17,842	10,975
Other (income) expense, net			(16)							142	29
Interest expense			233							2,689	289
(Loss) income from continuing operations before taxes			3,958							15,011	10,657
Income tax benefit										384
(Loss) income from continuing operations			3,958							14,627	10,657
Net (loss) income			3,958							14,627	10,657
Net (loss) income attributable to member of Summit Materials, LLC			3,958							14,627	10,657
Comprehensive (loss) income attributable to member of Summit Materials, LLC			$ 2,194							$ 3,096	$ 8,893

Senior Notes' Guarantor and Non

Senior Notes' Guarantor and Non-Guarantor Financial Information - Schedule of Condensed Consolidating Statements of Cash Flows (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 26, 2015	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Condensed Financial Statements, Captions [Line Items]
Cash - end of period	$ 5,482	$ 5,482	$ 6,729	$ 13,215	$ 14,917	$ 27,431
Net cash (used in) provided by operating activities		(18,927)	(10,836)	79,089	66,412	62,279
Cash flow from investing activities:
Acquisitions, net of cash acquired		(505,466)	(351,941)	(397,854)	(61,601)	(48,757)
Purchase of property, plant and equipment		(69,672)	(64,244)	(76,162)	(65,999)	(45,488)
Proceeds from the sale of property, plant, and equipment		8,883	9,575	13,366	16,085	8,836
Other		610	757	(630)		69
Net cash (used for) provided by investing activities		(565,645)	(405,853)	(461,280)	(111,515)	(85,340)
Cash flow from financing activities:
Proceeds from investment by member		490,916	24,350	27,617
Capital issuance costs		(12,539)
Net proceeds from debt issuance		1,415,750	657,217	762,250	234,681	726,442
Payments on long-term debt		(1,251,407)	(258,337)	(389,270)	(188,424)	(697,438)
Payments on long-term debt				(389,270)	(188,424)	(697,438)
Payments on acquisition-related liabilities		(15,018)	(5,807)	(10,935)	(9,801)	(7,519)
Financing costs		(10,911)	(8,834)	(9,085)	(3,864)	(13,081)
Distributions from partnership	(14,600)	(39,952)
Other			(88)	(88)	(3)	(702)
Net cash provided by (used for) financing activities		576,839	408,501	380,489	32,589	7,702
Net increase (decrease) in cash		(7,733)	(8,188)	(1,702)	(12,514)	(15,359)
Cash - Beginning of period		13,215	14,917	14,917	27,431	42,790
Cash - end of period	5,482	5,482	6,729	13,215	14,917	27,431
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Cash - end of period	(12,662)	(12,662)	(10,469)	(7,112)	(2,540)	(5,324)
Net cash (used in) provided by operating activities		(167)	(1,319)	(2,000)		(238)
Cash flow from investing activities:
Other			1,166	1,354
Net cash (used for) provided by investing activities			1,166	1,354
Cash flow from financing activities:
Proceeds from investment by member			(1,353)	(1,354)
Loans received from and payments made on loans from other Summit Companies		(6,439)	(7,923)	(4,572)	2,784	(5,324)
Payments on long-term debt		1,056
Other			1,500	2,000		238
Net cash provided by (used for) financing activities		(5,383)	(7,776)	(3,926)	2,784	(5,086)
Net increase (decrease) in cash		(5,550)	(7,929)	(4,572)	2,784	(5,324)
Cash - Beginning of period		(7,112)	(2,540)	(2,540)	(5,324)
Cash - end of period	(12,662)	(12,662)	(10,469)	(7,112)	(2,540)	(5,324)
Scenario, Previously Reported [Member]
Cash flow from financing activities:
Distributions from partnership		(26,400)
Summit Materials LLC (Parent) [Member]
Condensed Financial Statements, Captions [Line Items]
Cash - end of period				10,837	10,375	697
Net cash (used in) provided by operating activities				(40,964)	(232)	4,845
Cash flow from investing activities:
Acquisitions, net of cash acquired				(181,754)
Purchase of property, plant and equipment				(4,534)	(3,359)	(762)
Net cash (used for) provided by investing activities				(186,288)	(3,359)	(762)
Cash flow from financing activities:
Proceeds from investment by member				27,617
Net proceeds from debt issuance				762,250	234,681	726,459
Loans received from and payments made on loans from other Summit Companies				(170,915)	(29,121)	(25,371)
Payments on long-term debt				(380,065)	(188,424)	(697,438)
Payments on acquisition-related liabilities				(2,000)
Financing costs				(9,085)	(3,864)	(13,081)
Other				(88)	(3)	(656)
Net cash provided by (used for) financing activities				227,714	13,269	(10,087)
Net increase (decrease) in cash				462	9,678	(6,004)
Cash - Beginning of period		10,837	10,375	10,375	697	6,701
Cash - end of period				10,837	10,375	697
Non-Wholly Owned Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Cash - end of period			3	2	9	397
Net cash (used in) provided by operating activities			(2,408)	11,776	9,003	12,806
Cash flow from investing activities:
Purchase of property, plant and equipment			(13,472)	(14,941)	(24,896)	(12,174)
Proceeds from the sale of property, plant, and equipment					3	69
Other				(1,387)
Net cash (used for) provided by investing activities			(13,472)	(16,328)	(24,893)	(12,105)
Cash flow from financing activities:
Net proceeds from debt issuance						(17)
Loans received from and payments made on loans from other Summit Companies			16,383	5,338	15,502	(295)
Payments on long-term debt			(509)
Payments on long-term debt				(793)
Net cash provided by (used for) financing activities			15,874	4,545	15,502	(312)
Net increase (decrease) in cash			(6)	(7)	(388)	389
Cash - Beginning of period		2	9	9	397	8
Cash - end of period			3	2	9	397
Wholly Owned Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Cash - end of period	1,025	1,025	1,013	697	3,442	30,981
Net cash (used in) provided by operating activities		112,541	28,727	102,219	44,746	36,649
Cash flow from investing activities:
Acquisitions, net of cash acquired		(505,466)	(170,187)	(216,100)	(61,601)	(48,757)
Purchase of property, plant and equipment		(65,001)	(46,575)	(55,222)	(36,629)	(31,818)
Proceeds from the sale of property, plant, and equipment		8,821	9,345	13,134	16,020	8,577
Other		610	(409)	(597)		69
Net cash (used for) provided by investing activities		(561,036)	(207,826)	(258,785)	(82,210)	(71,929)
Cash flow from financing activities:
Loans received from and payments made on loans from other Summit Companies		1,047,015	189,243	173,166	19,726	39,783
Payments on long-term debt		(583,340)	(6,766)
Payments on long-term debt				(8,412)
Payments on acquisition-related liabilities		(14,852)	(4,307)	(8,935)	(9,801)	(7,519)
Other			(1,500)	(2,000)
Net cash provided by (used for) financing activities		448,823	176,670	153,819	9,925	32,264
Net increase (decrease) in cash		328	(2,429)	(2,747)	(27,539)	(3,016)
Cash - Beginning of period		697	3,442	3,442	30,981	33,997
Cash - end of period	1,025	1,025	1,013	697	3,442	30,981
Wholly Owned Guarantors [Member] | Scenario, Previously Reported [Member]
Condensed Financial Statements, Captions [Line Items]
Cash - end of period				695
Cash flow from financing activities:
Cash - Beginning of period		695
Cash - end of period				695
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Cash - end of period				8,793	3,631	680
Net cash (used in) provided by operating activities				8,058	12,895	8,217
Cash flow from investing activities:
Purchase of property, plant and equipment				(1,465)	(1,115)	(734)
Proceeds from the sale of property, plant, and equipment				232	62	190
Net cash (used for) provided by investing activities				(1,233)	(1,053)	(544)
Cash flow from financing activities:
Proceeds from investment by member				1,354
Loans received from and payments made on loans from other Summit Companies				(3,017)	(8,891)	(8,793)
Other						(284)
Net cash provided by (used for) financing activities				(1,663)	(8,891)	(9,077)
Net increase (decrease) in cash				5,162	2,951	(1,404)
Cash - Beginning of period		8,793	3,631	3,631	680	2,084
Cash - end of period				8,793	3,631	$ 680
Issuers [Member]
Condensed Financial Statements, Captions [Line Items]
Cash - end of period	8,989	8,989	12,936	10,837	10,375
Net cash (used in) provided by operating activities		(140,504)	(36,504)
Cash flow from investing activities:
Acquisitions, net of cash acquired			(181,754)
Purchase of property, plant and equipment		(3,743)	(3,674)
Net cash (used for) provided by investing activities		(3,743)	(185,428)
Cash flow from financing activities:
Proceeds from investment by member		490,916	24,350
Capital issuance costs		(12,539)
Net proceeds from debt issuance		1,415,750	657,217
Loans received from and payments made on loans from other Summit Companies		(1,031,576)	(195,590)
Payments on long-term debt		(669,123)	(251,062)
Payments on acquisition-related liabilities		(166)	(1,500)
Financing costs		(10,911)	(8,834)
Distributions from partnership		(39,952)
Other			(88)
Net cash provided by (used for) financing activities		142,399	224,493
Net increase (decrease) in cash		(1,848)	2,561
Cash - Beginning of period		10,837	10,375	10,375
Cash - end of period	8,989	8,989	12,936	10,837	10,375
Non Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Cash - end of period	8,130	8,130	3,246	8,793	3,631
Net cash (used in) provided by operating activities		9,203	668
Cash flow from investing activities:
Purchase of property, plant and equipment		(928)	(523)
Proceeds from the sale of property, plant, and equipment		62	230
Net cash (used for) provided by investing activities		(866)	(293)
Cash flow from financing activities:
Proceeds from investment by member			1,353
Loans received from and payments made on loans from other Summit Companies		(9,000)	(2,113)
Net cash provided by (used for) financing activities		(9,000)	(760)
Net increase (decrease) in cash		(663)	(385)
Cash - Beginning of period		8,793	3,631	3,631
Cash - end of period	$ 8,130	$ 8,130	$ 3,246	$ 8,793	$ 3,631

Supplementary Data (Unaudite111

Supplementary Data (Unaudited) - Supplemental Financial Information (Detail) - USD ($) $ in Thousands	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Selected Quarterly Financial Data [Abstract]
Revenue	$ 471,905	$ 334,086	$ 394,759	$ 324,295	$ 151,091	$ 238,267	$ 316,263	$ 254,842	$ 106,829	$ 1,030,835	$ 870,145	$ 1,204,231	$ 916,201	$ 926,254
Operating income (loss)	83,357	23,307	47,749	33,922	(35,019)	(57,742)	37,895	13,731	(41,861)	66,651	46,652	69,959	(47,977)	15,415
Income (loss) from continuing operations	34,106	4,753	28,110	13,832	(53,048)	(70,191)	22,950	244	(56,154)	(46,165)	(11,106)	(6,353)	(103,151)	(47,031)
Loss (income) from discontinued operations	(57)	285	(7)	(369)	20	271	160	(26)	123	(815)	(356)	(71)	528	3,546
Net income (loss)	$ 34,163	$ 4,468	$ 28,117	$ 14,201	$ (53,068)	$ (70,462)	$ 22,790	$ 270	$ (56,277)	$ (45,350)	$ (10,750)	$ (6,282)	$ (103,679)	$ (50,577)

Summary of Organization and 112

Summary of Organization and Significant Accounting Policies - Schedule of Carrying Value and Fair Value of Financial Instruments (Detail) - USD ($)	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Debt Instrument [Line Items]
Long-term debt, Carrying Value	$ 1,156,193,000	$ 1,064,917,000	$ 662,987,000
Level 2 [Member]
Debt Instrument [Line Items]
Long-term debt, Fair Value	1,155,557,000	1,101,873,000	696,500,000
Long-term debt, Carrying Value	1,156,193,000	1,064,917,000	$ 663,000,000
Level 3 [Member]
Debt Instrument [Line Items]
Current portion of deferred consideration and noncompete obligations, Fair Value	13,132,000	16,027,000
Long term portion of deferred consideration and noncompete obligations, Fair Value	30,609,000	37,357,000
Current portion of deferred consideration and noncompete obligations, Carrying Value	13,132,000	16,027,000
Long term portion of deferred consideration and noncompete obligations, Carrying Value	$ 30,609,000	$ 37,357,000

Summary of Organization and 113

Summary of Organization and Significant Accounting Policies - Schedule of Carrying Value and Fair Value of Financial Instruments (Parenthetical) (Detail) - USD ($)	Sep. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Debt Instrument [Line Items]
Current portion of debt	$ 8,100,000	$ 5,300,000
Remaining borrowing capacity	60,000,000		$ 26,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Remaining borrowing capacity	$ 60,000,000	$ 0

Reorganization - Additional Inf

Reorganization - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Reorganization Items [Line Items]
Number of LP Units outstanding	69,007,297
Class A common shares		28,571,429
Vesting period of leverage restoration options	4 years
General and Administrative Expense Costs [Member]
Reorganization Items [Line Items]
Modification charge recognized in general and administrative costs	$ 14.5
Common Class A [Member]
Reorganization Items [Line Items]
Class A common shares	1,029,183
2015 Omnibus Equity Incentive Plan [Member] | Common Class A [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
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
Share-based Compensation Award, Tranche One [Member] | 2015 Omnibus Equity Incentive Plan [Member]
Reorganization Items [Line Items]
Percentage of performance-vesting options	25.00%
Class C Units [Member] | Common Class A [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

Debt - Summary of Activity for

Debt - Summary of Activity for Deferred Financing Fees (Detail) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Equity Method Investments And Cost Method Investments [Abstract]
Beginning balance	$ 17,215	$ 11,485	$ 11,485
Loan origination fees	10,911	9,281
Amortization	(2,731)	(2,875)	(252)	$ (3,256)	$ (3,266)
Write off of deferred financing fees	(12,135)			(3,100)
Ending balance	$ 13,260	$ 17,891	$ 17,215	$ 11,485