Continental Cement Company, L.L.C. 10-K 23 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 27, 2014	Jun. 28, 2014	Feb. 23, 2015
Document Information [Line Items]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	27-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	CK0001571274
Entity Registrant Name	Continental Cement Company, L.L.C.
Entity Central Index Key	1571274
Current Fiscal Year End Date	-15
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Public Float		$0
Common Class A [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding			100
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding			100,000,000

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Current assets:
Cash	$2	$9
Accounts receivable, net	9,469	7,353
Due from Summit Materials	4,095	2,990
Inventories	8,696	10,402
Other current assets	509	482
Total current assets	22,771	21,236
Property, plant and equipment, net	307,286	306,204
Goodwill	24,096	24,096
Other assets	14,607	12,576
Total assets	368,760	364,112
Current liabilities:
Current portion of long-term debt due to Summit Materials	1,273	1,018
Accounts payable	7,599	10,165
Accrued expenses	10,926	9,997
Total current liabilities	19,798	21,180
Long-term debt due to Summit Materials	153,318	154,590
Pension and post-retirement benefit obligations	22,352	19,457
Other noncurrent liabilities	2,435	850
Total liabilities	197,903	196,077
Commitments and contingencies (see note 9)
Redeemable members' interest (100,000,000 Class B units issued and authorized)	34,543	23,450
Member's interest:
Member's equity (100 Class A units issued and authorized)	135,242	135,180
Retained earnings	13,961	17,029
Accumulated other comprehensive loss	-12,889	-7,624
Total member's interest	136,314	144,585
Total liabilities, redeemable members' interest and member's interest	$368,760	$364,112

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical)	Dec. 27, 2014	Dec. 28, 2013
Class B Units [Member]
Redeemable, Class B units issued	100,000,000	100,000,000
Redeemable, Class B units authorized	100,000,000	100,000,000
Member's equity, units issued	100,000,000
Class A Units [Member]
Member's equity, units issued	100	100
Member's equity, units authorized	100	100

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
Revenue from third parties:
Product	$75,627	$64,181	$65,213
Service	15,662	15,490	13,366
Revenue from related parties:
Product	18,775	16,578	16,303
Total revenue	110,064	96,249	94,882
Cost of revenue (excluding items shown separately below):
Product	58,716	46,137	49,541
Service	9,234	9,105	8,778
Total cost of revenue	67,950	55,242	58,319
General and administrative expenses	7,356	8,367	6,706
Depreciation, depletion, amortization and accretion	15,052	11,812	10,479
Operating income	19,706	20,828	19,378
Other expense (income), net	3	-90	131
Interest expense	11,678	11,053	12,622
Net income	$8,025	$9,865	$6,625

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$8,025	$9,865	$6,625
Other comprehensive (loss) income:
Postretirement curtailment adjustment	-1,346
Postretirement liability adjustment	-3,919	4,407	-3,648
Other comprehensive income (loss)	-5,265	4,407	-3,648
Comprehensive income	$2,760	$14,272	$2,977

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income	$8,025	$9,865	$6,625
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion, amortization and accretion	15,031	11,812	10,479
Other	1,244	801	-78
(Increase) decrease in operating assets:
Accounts receivable, net	-2,456	2,695	-1,924
Inventories	1,705	-3,329	2,841
Other current assets	-27	333	58
Other assets	-892	-1,304	308
(Decrease) increase in operating liabilities:
Accounts payable	-1,032	2,093	-907
Accrued expenses	-2,102	-1,574	6,685
Pension and post-retirement benefit obligations	-2,370	-1,704	-1,368
Other liabilities		-1,099	-340
Net cash provided by operating activities	17,126	18,589	22,379
Cash flows from investing activities:
Loans to affiliates		7,118	-10,220
Purchase of property, plant and equipment	-15,959	-25,594	-12,805
Other	-1,387	3	-10
Net cash used for investing activities	-17,346	-18,473	-23,035
Cash flows from financing activities:
Proceeds from borrowing			7,000
Principal payments on long-term debt	-1,048	-750	-5,783
Book overdraft	2,820	44
Net payments to Summit Materials	-1,559
Other			-17
Net cash provided by (used for) financing activities	213	-706	1,200
Net (decrease) increase in cash	-7	-590	544
Cash - beginning of period	9	599	55
Cash - end of period	2	9	599
Supplemental disclosures of cash flow information
Cash interest paid	11,728	11,488	7,353
Non cash financing activities:
Proceeds on borrowings due to Summit Materials			156,842
Repayment by Summit Materials of long-term debt and accrued interest			($156,842)

Consolidated_Statements_of_Cha

Consolidated Statements of Changes in Redeemable Members' Interest and Member's Interest (USD $)	3 Months Ended				12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Mar. 29, 2014	Dec. 28, 2013	Mar. 30, 2013	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
Beginning balance, Redeemable members' interest		$23,450		$22,850	$23,450	$22,850	$22,250
Accretion, Redeemable members' interest					11,093	600	600
Other comprehensive income, Redeemable members' interest					0	0	0
Net income, Redeemable members' interest					0	0	0
Share-based compensation, Redeemable members' interest					0	0	0
Ending balance, Redeemable members' interest	34,543		23,450		34,543	23,450	22,850
Beginning balance		144,585		130,851	144,585	130,851	128,412
Accretion					-11,093	-600	-600
Other comprehensive income					-5,265	4,407	-3,648
Net income	6,034	-8,153	6,668	-11,232	8,025	9,865	6,625
Share-based compensation					62	62	62
Ending balance	136,314		144,585		136,314	144,585	130,851
Member's Equity [Member]
Beginning balance		135,180		135,118	135,180	135,118	135,056
Accretion
Other comprehensive income
Net income
Share-based compensation					62	62	62
Ending balance	135,242		135,180		135,242	135,180	135,118
Retained Earnings [Member]
Beginning balance		17,029		7,764	17,029	7,764	1,739
Accretion					-11,093	-600	-600
Other comprehensive income
Net income					8,025	9,865	6,625
Share-based compensation
Ending balance	13,961		17,029		13,961	17,029	7,764
Accumulated Other Comprehensive Loss [Member]
Beginning balance		-7,624		-12,031	-7,624	-12,031	-8,383
Accretion
Other comprehensive income					-5,265	4,407	-3,648
Net income
Share-based compensation
Ending balance	($12,889)		($7,624)		($12,889)	($7,624)	($12,031)

Summary_of_Organization_and_Si

Summary of Organization and Significant Accounting Policies	12 Months Ended
	Dec. 27, 2014
Accounting Policies [Abstract]
Summary of Organization and Significant Accounting Policies	-1	Summary of Organization and Significant Accounting Policies
		(a)	Business Activities and Organization
	Continental Cement Company, L.L.C. ( “Continental Cement”) produces Portland cement at its plant located in Hannibal, Missouri. Cement distribution terminals are maintained in Hannibal and St. Louis, Missouri and Bettendorf, Iowa. Continental Cement’s primary customers are ready-mixed concrete and concrete products producers and contractors located in the Midwestern United States.
	Green America Recycling, L.L.C. (“GAR”), a wholly owned subsidiary of Continental Cement, is engaged in the business of securing, processing and blending hazardous and nonhazardous waste materials primarily for use as supplemental fuels in Continental Cement’s manufacturing process. GAR’s primary customers are commercial transportation disposal facilities and petroleum and chemical manufacturers located in the continental United States.
	Continental Cement, a Delaware limited liability company, is governed by the Amended and Restated Continental Cement Limited Liability Company Agreement (as amended, the “LLC Agreement”). As such, liability of the Continental Cement’s members is generally limited to the amount of their net investment in Continental Cement. Continental Cement is an indirect non–wholly owned subsidiary of Summit Materials, LLC (“Summit Materials”).
	In 2013, Continental Cement changed its fiscal year from a calendar year to a 52-53 week year with each quarter composed of 13 weeks ending on a Saturday, consistent with that of Summit Materials. Continental Cement’s fiscal year end in 2014 and 2013 was December 27 and December 28, respectively, compared to the calendar year ended December 31 in 2012. The effect of this change to Continental Cement’s financial position, results of operations and liquidity was immaterial.
		(b)	Principles of Consolidation
	The consolidated financial statements include the accounts of Continental Cement and its wholly owned subsidiary, GAR (collectively the “Company”). All significant intercompany balances and transactions have been eliminated.
		(c)	Use of Estimates
	The consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America, which require management to make estimates and assumptions that affect the reported amounts and disclosures in the consolidated financial statements. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities and reported amounts of expenses. Such estimates include the valuation of accounts receivable, inventories, goodwill, intangible and other long-lived assets, pension and other postretirement obligations, asset retirement obligations and the redeemable members’ interest. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment. Management adjusts such estimates and assumptions when circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ significantly from estimates made. Changes in estimates, including those resulting from continuing changes in the economic environment, will be reflected in the Company’s consolidated financial statements when the change in estimate occurs.
		(d)	Business and Credit Concentrations
	The Company’s customers are primarily located in Missouri, Iowa and Illinois. The Company’s accounts receivable balances are due primarily from ready-mixed concrete and concrete products producers and contractors within this area. Collection of these accounts is therefore dependent on the economic conditions of the area. However, credit granted within the Company’s trade area has been granted to a wide variety of customers, and management does not believe that any significant concentrations of credit exist with respect to individual customers or groups of customers who are engaged in similar activities that would be similarly affected by changes in economic or other conditions. The Company had approximately 15%, 16% and 13%, of cement sales with companies owned by a certain minority owner of the Company for the years ended December 27, 2014, December 28, 2013 and December 31, 2012, respectively.
		(e)	Accounts Receivable
	Accounts receivable are stated at the amount management expects to collect from outstanding balances. Management provides for probable uncollected amounts through a charge to earnings and a credit to the allowance for doubtful accounts based on its assessment of the status of individual accounts. In establishing the allowance, management considers historical losses adjusted to take into account current market conditions and customers’ financial condition, the amount of receivables in dispute, the current receivables aging and current payment terms. Balances that are still outstanding after management has used reasonable collection efforts are written off through a charge to the allowance for doubtful accounts. Changes in the allowance for doubtful accounts have not been material to the consolidated financial statements.
		(f)	Revenue Recognition
	Revenue from the sale of cement is recognized when evidence of an arrangement exists, the fee is fixed or determinable, title passes, which is generally when the product is shipped, and collection is reasonably assured. Cement sales are recorded net of discounts, allowances and sales taxes, as applicable. The Company records freight revenue on a net basis together with freight costs within cost of sales.
	Revenue from the receipt of waste fuels is recognized when the waste is accepted and a corresponding liability is recognized for the costs to process the waste into fuel for the manufacturing of cement or to ship the waste offsite for disposal in accordance with applicable regulations.
		(g)	Inventories
	Inventories of raw materials, work in process and finished goods are carried at the lower of cost (determined using the average cost method) or market. If items become obsolete or otherwise unusable, they will be charged to costs of production when that determination is made by management.
		(h)	Property, Plant and Equipment, net
	Property, plant and equipment are recorded at cost, less accumulated depreciation and depletion. Expenditures for additions and improvements that significantly add to the productive capacity or extend the useful life of an asset are capitalized. Repair and maintenance costs that do not substantially expand productive capacity or extend the life of property, plant and equipment are expensed as incurred.
	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 is computed on a straight-line basis. These estimated useful lives are 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
	Other			2—10 years
	Depletion of mineral reserves is calculated over proven and probable reserves by the units of production method on a site-by-site basis.
	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 may be at a significantly lower level than the level at which goodwill is tested for impairment. The lowest level of largely independent identifiable cash flows is at the cement operations. 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 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, considering the estimated future cash flows from its use and eventual disposition. Such indicators may include, among others, deterioration in general economic conditions, negative developments in equity and credit markets, 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.
		(i)	Accrued Mining Reclamation
	The Company's mining reclamation obligations are based on management’s estimate of future cost requirements to reclaim property at quarry sites. Estimates of these obligations have been developed based on management’s interpretation of current requirements and proposed regulatory changes and are intended to approximate fair value. The obligations were estimated based on reclamation costs at the time of the estimate, inflated until the expected time of payment using an inflation rate of 2.5%, and then discounted back to present value using a risk-free rate on obligations of similar maturity, adjusted to reflect the Company’s credit rating. Changes in the credit-adjusted, risk-free rate do not change recorded liabilities. However, subsequent increases in the recognized obligations are measured using a current credit-adjusted, risk-free rate. Decreases in the recognized obligations are measured at the initial credit-adjusted, risk-free rate.
	Significant changes in inflation rates or the amount or timing of future cost estimates typically result in both (1) a current adjustment to the recorded liability (and corresponding adjustment to the asset) and (2) a change in accretion of the liability and depreciation of the asset to be recorded prospectively over the remaining capacity of the unmined quarry.
		(j)	Goodwill
	Goodwill is the excess of cost over the fair value of net assets of businesses acquired and was $24.1 million as of December 27, 2014 and December 28, 2013. Goodwill is not amortized, but is tested annually for impairment and whenever events or circumstances change that would make it more likely than not that an impairment may have occurred.
	The Company performs an annual impairment analysis as of the first day of the fourth quarter of each fiscal year for its one reporting unit. The goodwill impairment test first uses a qualitative approach to determine whether it is more likely than not that the estimated fair value of a reporting unit is less than its carrying amount. If, as a result of the qualitative assessment, it is determined that an impairment is more likely than not, the two-step quantitative impairment test is then performed, otherwise further analysis is not required. The two-step quantitative impairment test compares the fair value of the reporting unit to its carrying value. Management estimates the fair value of the reporting unit primarily based on the discounted projected cash flows of the underlying operations. A number of significant assumptions and estimates are required to forecast operating cash flows, including macroeconomic trends in the private construction and public infrastructure industries, expected success in securing future sales and the appropriate interest rate used to discount the projected cash flows. During the 2014 qualitative review of goodwill, management concluded that it was more likely than not that the estimated fair value of the Company exceeded its carrying value and during the 2013 quantitative review of goodwill, management concluded that the estimated fair value of the reporting unit was substantially in excess of its carrying value, resulting in no indication of impairment. The Company has recorded no goodwill impairment charges to date.
		(k)	Income Taxes
	Continental Cement and GAR are limited liability companies that pass their tax attributes for federal and state tax purposes to their members and are generally not subject to federal or state income tax.
		(l)	Reclassifications
	Certain amounts have been reclassified in prior periods to conform to the presentation in the consolidated financial statements as of and for the year ended December 27, 2014.

Accounts_Receivable_Net

Accounts Receivable, Net	12 Months Ended
	Dec. 27, 2014
Receivables [Abstract]
Accounts Receivable, Net	-2	Accounts Receivable, net
	Accounts receivable, net consisted of the following as of December 27, 2014 and December 28, 2013:
			2014			2013
	Trade accounts receivable from unaffiliated entities		$	8,366		$	6,961
	Trade accounts receivable from related parties			1,470			422
	Accounts receivable			9,836			7,383
	Less: allowance for doubtful accounts			(367	)		(30	)
	Accounts receivable, net		$	9,469		$	7,353

Inventories

Inventories	12 Months Ended
	Dec. 27, 2014
Inventory Disclosure [Abstract]
Inventories	-3	Inventories
	Inventories consisted of the following as of December 27, 2014 and December 28, 2013:
			2014		2013
	Raw materials		$	1,099	$	972
	Work-in-process			1,801		2,623
	Finished goods			5,796		6,807
	Total inventories		$	8,696	$	10,402

Property_Plant_and_Equipment_N

Property, Plant and Equipment, Net	12 Months Ended
	Dec. 27, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, Net	-4	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		$	32,195		$	16,524
	Land (non-mineral bearing)			4,605			4,605
	Buildings and improvements			40,962			40,795
	Plants, machinery and equipment			266,310			247,681
	Mobile equipment and barges			8,244			8,060
	Office equipment			2,420			1,845
	Construction in progress			1,611			23,394
	Other			1,721			—
	Property, plant and equipment			358,068			342,904
	Less accumulated depreciation, depletion and amortization			(50,782	)		(36,700	)
	Property, plant and equipment, net		$	307,286		$	306,204
	The Company completed development of an underground mine in 2014 through which over 200 years of limestone reserves may be accessed. Limestone is a raw material used in the production of cement. The $15.6 million of underground mine development costs included in construction in progress as of December 28, 2013 were included in land (mineral bearing) as of December 27, 2014. Capitalized costs for mine development include costs incurred for site preparation and development of the mine.
	Depreciation and depletion expense of property, plant and equipment was $14.8 million, $11.6 million and $10.3 million, for the years ended December 27, 2014, December 28, 2013 and December 31, 2012, respectively.
	Property, plant and equipment at December 27, 2014 included $1.7 million of capital leases for certain equipment with accumulated amortization of approximately $22 thousand. The equipment leases generally have terms of less than five years.
	Approximately $0.2 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 sheet.

Accrued_Expenses

Accrued Expenses	12 Months Ended
	Dec. 27, 2014
Payables and Accruals [Abstract]
Accrued Expenses	-5	Accrued Expenses
	Accrued expenses and other liabilities consisted of the following as of December 27, 2014 and December 28, 2013:
			2014		2013
	Interest due to Summit Materials		$	3,804	$	3,848
	Interest due to noncontrolling member			—		723
	Postretirement benefits other than pensions, current portion			1,041		1,268
	Bonus liability			903		884
	Payroll, insurance and benefits			911		758
	Costs to remove barge from waterway			380		880
	Professional fees			70		340
	Current portion of capital lease obligations			215		—
	Other			3,602		1,296
	Total		$	10,926	$	9,997

LongTerm_Debt

Long-Term Debt	12 Months Ended
	Dec. 27, 2014
Debt Disclosure [Abstract]
Long-Term Debt	-6	Long-Term Debt
	Long-term debt due to Summit Materials, including the current portion of long-term debt, was $154.6 million and
	$155.6 million as of December 27, 2014 and December 28, 2013, respectively. Interest costs incurred were $11.1 million in each of the years ended December 27, 2014 and December 28, 2013 and $12.6 million in the year ended December 31, 2012. The interest rate in effect at December 27, 2014 was 3.7%.
	The terms of the agreements governing Summit Materials’ debt limit certain transactions of its subsidiaries, including those of the Company, such as its ability to incur additional indebtedness or issue certain preferred shares, pay dividends to noncontrolling members, redeem stock or make other distributions, make certain investments, sell or transfer certain assets, create liens, consolidate, merge, sell or otherwise dispose of all or substantially all of its assets, enter into certain transactions with affiliates.
	Continental Cement is named as a guarantor of Summit Materials’ debt, for which it has pledged substantially all of its assets as collateral. Continental Cement provides a joint and several, full and unconditional guarantee of Summit Materials’ debt. Summit Materials is and has been current on all required principal and interest payments. As of December 27, 2014, approximately $94.3 million and $60.3 million of the Company’s long-term debt due to Summit Materials represented the amount of Summit Materials’ debt under a senior secured credit facility and senior notes, respectively, that has been allocated to the Company.
	Future maturities of long-term debt due to Summit Materials as of December 27, 2014 are as follows:
	2015			1,273
	2016			1,018
	2017			1,018
	2018			764
	2019			90,194
	Thereafter			60,324
	Total		$	154,591

Members_Interest

Members' Interest	12 Months Ended
	Dec. 27, 2014
Equity [Abstract]
Members' Interest	-7	Members’ Interest
	Business affairs of the Company are managed by a board of directors (the “Board”) composed of up to seven Directors. As of December 27, 2014 and December 28, 2013, Summit Materials was entitled to appoint four directors to the Board and members representing the noncontrolling interest were entitled to appoint three directors to the Board. Any director may be removed from the Board with or without cause at any time by the directors entitled to appoint such Director. The LLC Agreement provides that resolutions of the Board generally require the consent of at least a majority of the Directors.
	Summit Materials indirectly owns 100 Class A Units of Continental Cement, which represent an approximately 70% economic interest in the Company and have a preference in liquidation to the Class B Units. The non-contolling members own 100,000,000 Class B Units, which 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, that Continental Cement Class A Units receive, prior to any distributions to the Class B Unitholders (the “Class B Unitholders”), 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 LLC Agreement provides Summit Materials 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 the Company, 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 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 Holdings, L.P.(“Summit Holdings”), an indirect parent of Summit Materials, or a parent entity of Summit Holdings. In December 2014, Summit Holdings 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., which will become the direct parent of Summit Holdings upon consummation of the proposed initial public offering, 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, an entity 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_Benefit_Plans

Employee Benefit Plans	12 Months Ended
	Dec. 27, 2014
Postemployment Benefits [Abstract]
Employee Benefit Plans	-8	Employee Benefit Plans
	Deferred Compensation Plan
	The Company sponsors an Employee 401(k) Savings Plan for all salaried employees and certain union employees. The plan provides for various required and discretionary Company matches of employees’ eligible compensation contributed to the plan and a discretionary profit sharing contribution as determined by the Company’s Board of Directors. The Company’s contributions to the plan were $0.6 million, $0.5 million and $0.4 million for the years ended December 27, 2014, December 28, 2013 and December 31, 2012, respectively.
	Defined Benefit Plans and Other Postretirement Benefits
	Continental Cement sponsors two noncontributory defined benefit pension plans for hourly and salaried employees. The plans are closed to new participants and benefits are frozen. Pension benefits for eligible hourly employees are based on a monthly pension factor for each year of credited service. Pension benefits for eligible salaried employees are generally based on years of service and average eligible compensation.
	Continental Cement also sponsors 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—The following information is as of December 27, 2014 and December 28, 2013 and for the years ended December 27, 2014, December 28, 2013 and December 29, 2012:
			2014						2013
			Pension			Healthcare			Pension			Healthcare
			benefits			& Life Ins.			benefits			& Life Ins.
	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, which has not yet been recognized in periodic benefit cost. 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
			benefits			& Life Ins.			benefits			& Life Ins.			benefits			& Life Ins.
	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 benefits			—			(1,346	)		—			—			—			—
	Special termination benefits			—			—			—			39			—			—
	Amortization of prior service credit			—			(174	)		—			(180	)		—			—
	Net periodic benefit cost		$	(105	)	$	(694	)	$	297		$	922		$	292		$	924
	Assumptions—Weighted-average assumptions used to determine the benefit obligations as of year-end 2014 and 2013 are:
			2014			2013
			Pension		Healthcare	Pension		Healthcare
			benefits		& Life Ins.	benefits		& Life Ins.
	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 the years ended December 27, 2014, December 28, 2013 and December 31, 2012:
			2014			2013			2012
			Pension		Healthcare	Pension		Healthcare	Pension		Healthcare
benefits			& Life Ins.		benefits	& Life Ins.		benefits	& Life Ins.
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 December 27, 2014 and December 28, 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 December 27, 2014 and December 28, 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—The defined benefit pension plans’ (the “Plans”) investment strategy is to minimize investment risk while generating acceptable returns. The Plans currently invest a relatively high proportion of their assets in fixed income securities, while the remainder is invested in equity securities, cash reserves and precious metals. The equity securities are diversified into funds with growth and value investment strategies. The target allocation for plan assets is as follows: fixed income securities –63%; equity securities – 30%; cash reserves –5%; and precious metals –2%. The Plans’ current investment allocations are within the tolerance of the target allocation.
Fair value determinations are based on the following hierarchy, which prioritizes the inputs used to measure fair value:
	•		Level 1—Quoted prices in active markets for identical assets and liabilities
	•		Level 2—Observable inputs, other than quoted prices, for similar assets or liabilities in active markets
	•		Level 3—Unobservable inputs, which includes the use of valuation models
The Company had no Level 3 investments as of or during the years ended December 27, 2014 and December 28, 2013.
At December 27, 2014 and December 28, 2013, the Plans’ assets were invested predominantly in publicly traded fixed-income securities and 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 equities include U.S. and international securities and equity funds. The Company estimates the fair value of the Plans’ assets using various valuation techniques and, to the extent available, quoted market prices in active markets or observable market inputs. The descriptions and fair value methodologies for the Plans’ assets are as follows:
Fixed Income Securities – Corporate and government bonds are classified as Level 2 assets, as they are either valued at quoted market prices from observable pricing sources at the reporting date or valued based upon comparable securities with similar yields and credit ratings.
Equity Securities — Equity securities are valued at the closing market price reported on a U.S. exchange where the security is actively traded and are therefore classified as Level 1 assets.
Cash - The carrying amounts of cash approximate fair value due to the short-term maturity.
Precious Metals — Precious metals are valued at the closing market price reported on a U.S. exchange where the security is actively traded and are therefore classified as Level 1 assets.
The fair value of the Plans’ assets by asset class and fair value hierarchy level as of December 27, 2014 and December 28, 2013 were as follows:
		2014
		Total fair			Quoted prices in active			Observable
		value			markets for identical			inputs (Level 2)
					assets (Level 1)
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
		value			markets for identical			inputs (Level 2)
					assets (Level 1)
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 Company expects to contribute approximately $1.1 million to its pension plans and $1.0 million to its healthcare and life insurance benefits plans in 2015.
The estimated benefit payments for each of the next five years and the five-year period thereafter are as follows:
		Pension			Healthcare and Life
		benefits			Insurance Benefits
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

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 27, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	-9	Commitments and Contingencies
	Litigation and Claims
	The Company is party to certain legal actions arising from the ordinary course of business activities. In the opinion of management, these actions are without merit or that the ultimate disposition, if any, resulting from them will not have a material effect on the Company’s financial position, results of operations or liquidity. The Company’s policy is to record legal fees as incurred.
	In February 2011, the Company incurred a property loss related to a sunken barge with cement product aboard. As of December 27, 2014 and December 28, 2013, the Company had a $0.4 million and $0.9 million, respectively, accrual for the estimated remaining costs to remove the barge.
	Environmental Remediation
	The Company’s manufacturing operations are subject to and affected by Federal, state and local laws and regulations relating to the environment, health and safety and other regulatory matters. These operations require environmental operating permits, which are subject to modification, renewal and revocation. The Company regularly monitors and reviews its operations, procedures and policies for compliance with these laws and regulations. Despite these compliance efforts, risk of environmental liability is inherent in the operation of Continental Cement’s business, as it is with other companies engaged in similar businesses and there can be no assurance that environmental liabilities will not have a material adverse effect on the Company in the future.
	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.

RelatedParty_Transactions

Related-Party Transactions	12 Months Ended
	Dec. 27, 2014
Related Party Transactions [Abstract]
Related-Party Transactions	-10	Related-Party Transactions
	Cement sales to companies owned by certain noncontrolling members of Continental Cement were approximately $14.3 million, $12.7 million and $12.5 million during the years ended December 27, 2014, December 28, 2013 and December 31, 2012, respectively, and accounts receivables due from these parties were approximately $1.2 million and $0.2 million as of December 27, 2014 and December 28, 2013, respectively.
	Cement sales to a subsidiary of Summit Materials were approximately $4.5 million, $4.5 million and $3.8 million for the years ended December 27, 2014, December 28, 2013 and December 31, 2012, respectively, and accounts receivable due from this party was approximately $0.3 million and $0.2 million as of December 27, 2014 and December 28, 2013, respectively.
	As of December 28, 2013, the Company had accrued interest payments of $0.7 million, respectively, due to a certain noncontrolling member for a related-party note, which was paid in 2014. The principal balance on the note was repaid in January 2012.
	The Company purchased equipment from a certain noncontrolling member for approximately $2.3 million in 2011, which was paid for in 2012.

Leasing_Arrangements

Leasing Arrangements	12 Months Ended
	Dec. 27, 2014
Leases [Abstract]
Leasing Arrangements	-11	Leasing Arrangements
	Rent expense incurred, including short term rentals, primarily related to land and equipment, was $0.4 million in each of the years ended December 27, 2014 and December 28, 2013 and $0.5 million in the year ended December 31, 2012.
	Minimum rental commitments under long-term operating and capital leases as of December 27, 2014, are as follows:
			Operating		Capital
			Leases		Leases
	2015		$	132	$	334
	2016			115		328
	2017			79		328
	2018			76		328
	2019			73		328

Supplementary_Data_Unaudited

Supplementary Data (Unaudited)	12 Months Ended
	Dec. 27, 2014
Quarterly Financial Information Disclosure [Abstract]
Supplementary Data (Unaudited)	-12	Supplementary Data (Unaudited)
	Supplemental financial information (unaudited) by quarter was as follows for the years ended December 27, 2014 and December 28, 2013:
			2014									2013
	(in thousands)		4Q		3Q		2Q		1Q			4Q		3Q		2Q		1Q
	Revenues		$	29,446	$	38,168	$	31,822	$	10,628		$	22,509	$	34,155	$	27,224	$	12,361
	Operating income (loss)			8,876		6,920		9,201		(5,291	)		9,259		10,965		9,053		(8,449	)
	Net income (loss)		$	6,034	$	3,964	$	6,180	$	(8,153	)	$	6,668	$	8,157	$	6,272	$	(11,232	)

Summary_of_Organization_and_Si1

Summary of Organization and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 27, 2014
Accounting Policies [Abstract]
Business Activities and Organization		(a)	Business Activities and Organization
	Continental Cement Company, L.L.C. ( “Continental Cement”) produces Portland cement at its plant located in Hannibal, Missouri. Cement distribution terminals are maintained in Hannibal and St. Louis, Missouri and Bettendorf, Iowa. Continental Cement’s primary customers are ready-mixed concrete and concrete products producers and contractors located in the Midwestern United States.
	Green America Recycling, L.L.C. (“GAR”), a wholly owned subsidiary of Continental Cement, is engaged in the business of securing, processing and blending hazardous and nonhazardous waste materials primarily for use as supplemental fuels in Continental Cement’s manufacturing process. GAR’s primary customers are commercial transportation disposal facilities and petroleum and chemical manufacturers located in the continental United States.
	Continental Cement, a Delaware limited liability company, is governed by the Amended and Restated Continental Cement Limited Liability Company Agreement (as amended, the “LLC Agreement”). As such, liability of the Continental Cement’s members is generally limited to the amount of their net investment in Continental Cement. Continental Cement is an indirect non–wholly owned subsidiary of Summit Materials, LLC (“Summit Materials”).
	In 2013, Continental Cement changed its fiscal year from a calendar year to a 52-53 week year with each quarter composed of 13 weeks ending on a Saturday, consistent with that of Summit Materials. Continental Cement’s fiscal year end in 2014 and 2013 was December 27 and December 28, respectively, compared to the calendar year ended December 31 in 2012. The effect of this change to Continental Cement’s financial position, results of operations and liquidity was immaterial.
Principles of Consolidation		(b)	Principles of Consolidation
	The consolidated financial statements include the accounts of Continental Cement and its wholly owned subsidiary, GAR (collectively the “Company”). All significant intercompany balances and transactions have been eliminated.
Use of Estimates		(c)	Use of Estimates
	The consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America, which require management to make estimates and assumptions that affect the reported amounts and disclosures in the consolidated financial statements. These estimates and the underlying assumptions affect the amounts of assets and liabilities reported, disclosures about contingent assets and liabilities and reported amounts of expenses. Such estimates include the valuation of accounts receivable, inventories, goodwill, intangible and other long-lived assets, pension and other postretirement obligations, asset retirement obligations and the redeemable members’ interest. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment. Management adjusts such estimates and assumptions when circumstances dictate. As future events and their effects cannot be determined with precision, actual results could differ significantly from estimates made. Changes in estimates, including those resulting from continuing changes in the economic environment, will be reflected in the Company’s consolidated financial statements when the change in estimate occurs.
Business and Credit Concentrations		(d)	Business and Credit Concentrations
	The Company’s customers are primarily located in Missouri, Iowa and Illinois. The Company’s accounts receivable balances are due primarily from ready-mixed concrete and concrete products producers and contractors within this area. Collection of these accounts is therefore dependent on the economic conditions of the area. However, credit granted within the Company’s trade area has been granted to a wide variety of customers, and management does not believe that any significant concentrations of credit exist with respect to individual customers or groups of customers who are engaged in similar activities that would be similarly affected by changes in economic or other conditions. The Company had approximately 15%, 16% and 13%, of cement sales with companies owned by a certain minority owner of the Company for the years ended December 27, 2014, December 28, 2013 and December 31, 2012, respectively.
Accounts Receivable		(e)	Accounts Receivable
	Accounts receivable are stated at the amount management expects to collect from outstanding balances. Management provides for probable uncollected amounts through a charge to earnings and a credit to the allowance for doubtful accounts based on its assessment of the status of individual accounts. In establishing the allowance, management considers historical losses adjusted to take into account current market conditions and customers’ financial condition, the amount of receivables in dispute, the current receivables aging and current payment terms. Balances that are still outstanding after management has used reasonable collection efforts are written off through a charge to the allowance for doubtful accounts. Changes in the allowance for doubtful accounts have not been material to the consolidated financial statements.
Revenue Recognition		(f)	Revenue Recognition
	Revenue from the sale of cement is recognized when evidence of an arrangement exists, the fee is fixed or determinable, title passes, which is generally when the product is shipped, and collection is reasonably assured. Cement sales are recorded net of discounts, allowances and sales taxes, as applicable. The Company records freight revenue on a net basis together with freight costs within cost of sales.
	Revenue from the receipt of waste fuels is recognized when the waste is accepted and a corresponding liability is recognized for the costs to process the waste into fuel for the manufacturing of cement or to ship the waste offsite for disposal in accordance with applicable regulations.
Inventories		(g)	Inventories
	Inventories of raw materials, work in process and finished goods are carried at the lower of cost (determined using the average cost method) or market. If items become obsolete or otherwise unusable, they will be charged to costs of production when that determination is made by management.
Property, Plant and Equipment, net		(h)	Property, Plant and Equipment, net
	Property, plant and equipment are recorded at cost, less accumulated depreciation and depletion. Expenditures for additions and improvements that significantly add to the productive capacity or extend the useful life of an asset are capitalized. Repair and maintenance costs that do not substantially expand productive capacity or extend the life of property, plant and equipment are expensed as incurred.
	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 is computed on a straight-line basis. These estimated useful lives are 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
	Other			2—10 years
	Depletion of mineral reserves is calculated over proven and probable reserves by the units of production method on a site-by-site basis.
	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 may be at a significantly lower level than the level at which goodwill is tested for impairment. The lowest level of largely independent identifiable cash flows is at the cement operations. 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 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, considering the estimated future cash flows from its use and eventual disposition. Such indicators may include, among others, deterioration in general economic conditions, negative developments in equity and credit markets, 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.
Accrued Mining Reclamation		(i)	Accrued Mining Reclamation
	The Company's mining reclamation obligations are based on management’s estimate of future cost requirements to reclaim property at quarry sites. Estimates of these obligations have been developed based on management’s interpretation of current requirements and proposed regulatory changes and are intended to approximate fair value. The obligations were estimated based on reclamation costs at the time of the estimate, inflated until the expected time of payment using an inflation rate of 2.5%, and then discounted back to present value using a risk-free rate on obligations of similar maturity, adjusted to reflect the Company’s credit rating. Changes in the credit-adjusted, risk-free rate do not change recorded liabilities. However, subsequent increases in the recognized obligations are measured using a current credit-adjusted, risk-free rate. Decreases in the recognized obligations are measured at the initial credit-adjusted, risk-free rate.
	Significant changes in inflation rates or the amount or timing of future cost estimates typically result in both (1) a current adjustment to the recorded liability (and corresponding adjustment to the asset) and (2) a change in accretion of the liability and depreciation of the asset to be recorded prospectively over the remaining capacity of the unmined quarry.
Goodwill		(j)	Goodwill
	Goodwill is the excess of cost over the fair value of net assets of businesses acquired and was $24.1 million as of December 27, 2014 and December 28, 2013. Goodwill is not amortized, but is tested annually for impairment and whenever events or circumstances change that would make it more likely than not that an impairment may have occurred.
	The Company performs an annual impairment analysis as of the first day of the fourth quarter of each fiscal year for its one reporting unit. The goodwill impairment test first uses a qualitative approach to determine whether it is more likely than not that the estimated fair value of a reporting unit is less than its carrying amount. If, as a result of the qualitative assessment, it is determined that an impairment is more likely than not, the two-step quantitative impairment test is then performed, otherwise further analysis is not required. The two-step quantitative impairment test compares the fair value of the reporting unit to its carrying value. Management estimates the fair value of the reporting unit primarily based on the discounted projected cash flows of the underlying operations. A number of significant assumptions and estimates are required to forecast operating cash flows, including macroeconomic trends in the private construction and public infrastructure industries, expected success in securing future sales and the appropriate interest rate used to discount the projected cash flows. During the 2014 qualitative review of goodwill, management concluded that it was more likely than not that the estimated fair value of the Company exceeded its carrying value and during the 2013 quantitative review of goodwill, management concluded that the estimated fair value of the reporting unit was substantially in excess of its carrying value, resulting in no indication of impairment. The Company has recorded no goodwill impairment charges to date.
Income Taxes		(k)	Income Taxes
	Continental Cement and GAR are limited liability companies that pass their tax attributes for federal and state tax purposes to their members and are generally not subject to federal or state income tax.
Reclassifications		(l)	Reclassifications
	Certain amounts have been reclassified in prior periods to conform to the presentation in the consolidated financial statements as of and for the year ended December 27, 2014.

Summary_of_Organization_and_Si2

Summary of Organization and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 27, 2014
Accounting Policies [Abstract]
Estimated Useful Lives of Assets	These estimated useful lives are 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
	Other	2—10 years

Accounts_Receivable_Net_Tables

Accounts Receivable, Net (Tables)	12 Months Ended
	Dec. 27, 2014
Receivables [Abstract]
Summary of Accounts Receivable, Net	Accounts receivable, net consisted of the following as of December 27, 2014 and December 28, 2013:
		2014			2013
	Trade accounts receivable from unaffiliated entities	$	8,366		$	6,961
	Trade accounts receivable from related parties		1,470			422
	Accounts receivable		9,836			7,383
	Less: allowance for doubtful accounts		(367	)		(30	)
	Accounts receivable, net	$	9,469		$	7,353

Inventories_Tables

Inventories (Tables)	12 Months Ended
	Dec. 27, 2014
Inventory Disclosure [Abstract]
Components of Inventories	Inventories consisted of the following as of December 27, 2014 and December 28, 2013:
		2014		2013
	Raw materials	$	1,099	$	972
	Work-in-process		1,801		2,623
	Finished goods		5,796		6,807
	Total inventories	$	8,696	$	10,402

Property_Plant_and_Equipment_N1

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	$	32,195		$	16,524
	Land (non-mineral bearing)		4,605			4,605
	Buildings and improvements		40,962			40,795
	Plants, machinery and equipment		266,310			247,681
	Mobile equipment and barges		8,244			8,060
	Office equipment		2,420			1,845
	Construction in progress		1,611			23,394
	Other		1,721			—
	Property, plant and equipment		358,068			342,904
	Less accumulated depreciation, depletion and amortization		(50,782	)		(36,700	)
	Property, plant and equipment, net	$	307,286		$	306,204

Accrued_Expenses_Tables

Accrued Expenses (Tables)	12 Months Ended
	Dec. 27, 2014
Payables and Accruals [Abstract]
Components of Accrued Expenses	Accrued expenses and other liabilities consisted of the following as of December 27, 2014 and December 28, 2013:
		2014		2013
	Interest due to Summit Materials	$	3,804	$	3,848
	Interest due to noncontrolling member		—		723
	Postretirement benefits other than pensions, current portion		1,041		1,268
	Bonus liability		903		884
	Payroll, insurance and benefits		911		758
	Costs to remove barge from waterway		380		880
	Professional fees		70		340
	Current portion of capital lease obligations		215		—
	Other		3,602		1,296
	Total	$	10,926	$	9,997

LongTerm_Debt_Tables

Long-Term Debt (Tables)	12 Months Ended
	Dec. 27, 2014
Debt Disclosure [Abstract]
Summary of Future Maturities of Long-Term Debt	Future maturities of long-term debt due to Summit Materials as of December 27, 2014 are as follows:
	2015		1,273
	2016		1,018
	2017		1,018
	2018		764
	2019		90,194
	Thereafter		60,324
	Total	$	154,591

Employee_Benefit_Plans_Tables

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 27, 2014
Postemployment Benefits [Abstract]
Changes in Projected Benefit Obligations Fair Value of Plan Assets and Funded Status of Plan	Obligations and Funded Status—The following information is as of December 27, 2014 and December 28, 2013 and for the years ended December 27, 2014, December 28, 2013 and December 29, 2012:
		2014						2013
		Pension			Healthcare			Pension			Healthcare
		benefits			& Life Ins.			benefits			& Life Ins.
	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
Schedule of Net Periodic Pension Benefit Cost and Other Comprehensive Income
		2014						2013						2012
		Pension			Healthcare			Pension			Healthcare			Pension			Healthcare
		benefits			& Life Ins.			benefits			& Life Ins.			benefits			& Life Ins.
	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 benefits		—			(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—Weighted-average assumptions used to determine the benefit obligations as of year-end 2014 and 2013 are:
		2014			2013
		Pension		Healthcare	Pension		Healthcare
		benefits		& Life Ins.	benefits		& Life Ins.
	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 the years ended December 27, 2014, December 28, 2013 and December 31, 2012:
		2014			2013			2012
		Pension		Healthcare	Pension		Healthcare	Pension		Healthcare
		benefits		& Life Ins.	benefits		& Life Ins.	benefits		& Life Ins.
	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 December 27, 2014 and December 28, 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 were as follows:
		2014
		Total fair			Quoted prices in active			Observable
		value			markets for identical			inputs (Level 2)
					assets (Level 1)
	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
		value			markets for identical			inputs (Level 2)
					assets (Level 1)
	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
		benefits			Insurance Benefits
	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

Leasing_Arrangements_Tables

Leasing Arrangements (Tables)	12 Months Ended
	Dec. 27, 2014
Leases [Abstract]
Minimum Rental Commitments under Long-Term Operating and Capital Leases	Minimum rental commitments under long-term operating and capital leases as of December 27, 2014, are as follows:
		Operating		Capital
		Leases		Leases
	2015	$	132	$	334
	2016		115		328
	2017		79		328
	2018		76		328
	2019		73		328

Supplementary_Data_Unaudited_T

Supplementary Data (Unaudited) (Tables)	12 Months Ended
	Dec. 27, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly Supplemental Financial Information	Supplemental financial information (unaudited) by quarter was as follows for the years ended December 27, 2014 and December 28, 2013:
		2014									2013
	(in thousands)	4Q		3Q		2Q		1Q			4Q		3Q		2Q		1Q
	Revenues	$	29,446	$	38,168	$	31,822	$	10,628		$	22,509	$	34,155	$	27,224	$	12,361
	Operating income (loss)		8,876		6,920		9,201		(5,291	)		9,259		10,965		9,053		(8,449	)
	Net income (loss)	$	6,034	$	3,964	$	6,180	$	(8,153	)	$	6,668	$	8,157	$	6,272	$	(11,232	)

Summary_of_Organization_and_Si3

Summary of Organization and Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
Organization And Significant Accounting Policies [Line Items]
Inflation rate	2.50%
Value of goodwill	24,096,000	24,096,000
Number of reporting unit for annual impairment analysis	1
Goodwill impairment charges	0	0
Impairment	0	0
Continental Cement Company L.L.C [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Organization And Significant Accounting Policies [Line Items]
Percentage of sale of cement	15.00%	16.00%	13.00%

Summary_of_Organization_and_Si4

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 lives of assets	7 years
Minimum [Member] | Plants, Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	20 years
Minimum [Member] | Mobile Equipment and Barges [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	15 years
Minimum [Member] | Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	3 years
Minimum [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	2 years
Maximum [Member] | Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	40 years
Maximum [Member] | Plants, Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	40 years
Maximum [Member] | Mobile Equipment and Barges [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	20 years
Maximum [Member] | Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	6 years
Maximum [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	10 years

Accounts_Receivable_Net_Summar

Accounts Receivable, Net - Summary of Accounts Receivable, Net (Detail) (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Receivables [Abstract]
Trade accounts receivable from unaffiliated entities	$8,366	$6,961
Trade accounts receivable from related parties	1,470	422
Accounts receivable	9,836	7,383
Less: allowance for doubtful accounts	-367	-30
Accounts receivable, net	$9,469	$7,353

Inventories_Components_of_Inve

Inventories - Components of Inventories (Detail) (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]
Raw materials	$1,099	$972
Work-in-process	1,801	2,623
Finished goods	5,796	6,807
Total inventories	$8,696	$10,402

Property_Plant_and_Equipment_N2

Property, Plant and Equipment, Net - Components of Property, Plant and Equipment (Detail) (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$358,068	$342,904
Less accumulated depreciation, depletion and amortization	-50,782	-36,700
Property, plant and equipment, net	307,286	306,204
Land (Mineral Bearing) and Asset Retirement Costs [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	32,195	16,524
Land (Non-Mineral Bearing) [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,605	4,605
Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	40,962	40,795
Plants, Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	266,310	247,681
Mobile Equipment and Barges [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	8,244	8,060
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2,420	1,845
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,611	23,394
Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$1,721

Property_Plant_and_Equipment_N3

Property, Plant and Equipment, Net - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
Impairment Effects on Earnings Per Share [Line Items]
Underground mine development costs	$15,600,000
Depreciation and depletion expense	14,800,000	11,600,000	10,300,000
Capital lease future obligation payments	200,000
Property, Plant and Equipment [Member]
Impairment Effects on Earnings Per Share [Line Items]
Capital leases for certain equipment	1,700,000
Capital leases for certain equipment accumulated amortization	$22,000
Capital lease term	5 years

Accrued_Expenses_Components_of

Accrued Expenses - Components of Accrued Expenses (Detail) (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Payables and Accruals [Abstract]
Interest due to Summit Materials	$3,804	$3,848
Interest due to noncontrolling member		723
Postretirement benefits other than pensions, current portion	1,041	1,268
Bonus liability	903	884
Payroll, insurance and benefits	911	758
Costs to remove barge from waterway	380	880
Professional fees	70	340
Current portion of capital lease obligations	215
Other	3,602	1,296
Total	$10,926	$9,997

LongTerm_Debt_Additional_Infor

Long-Term Debt - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
Long Term Debt Maturities Repayments Of Principal [Line Items]
Debt due to Summit Materials	$154,591,000	$155,600,000
Interest costs on debt	11,100,000	11,100,000	12,600,000
Senior Notes [Member]
Long Term Debt Maturities Repayments Of Principal [Line Items]
Debt due to Summit Materials	60,300,000
Senior Secured Credit Facility, Revolver [Member]
Long Term Debt Maturities Repayments Of Principal [Line Items]
Interest rate on borrowings	3.70%
Senior Secured Credit Facilities [Member]
Long Term Debt Maturities Repayments Of Principal [Line Items]
Debt due to Summit Materials	$94,300,000

LongTerm_Debt_Summary_of_Futur

Long-Term Debt - Summary of Future Maturities of Long-Term Debt (Detail) (USD $)	Dec. 27, 2014	Dec. 28, 2013
In Thousands, unless otherwise specified
Debt Disclosure [Abstract]
2015	$1,273
2016	1,018
2017	1,018
2018	764
2019	90,194
Thereafter	60,324
Total	$154,591	$155,600

Members_Interest_Additional_In

Members' Interest - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Sep. 27, 2014
	Directors	Directors
Equity [Line Items]
Number of directors	7
Directors to be appointed	4	4
Directors to be appointed by noncontrolling interest members	3	3
Anticipated redemption date	2016-05
Percentage of number of outstanding units	1.47%
Common units issued, value	$35
Non interest bearing note payable	15
Debt instrument payment term	Six aggregate annual installments of $2.5 million, beginning on the first anniversary of the closing of the initial public offering.
Amount of annual installment	2.5
Class A Units [Member]
Equity [Line Items]
Member's equity, units issued	100
Economic interest percentage of classes of capital units	70.00%
Interest on capital contributions	11.00%
Percentage of priority return	80.00%
Class B Units [Member]
Equity [Line Items]
Member's equity, units issued	100,000,000
Economic interest percentage of classes of capital units	30.00%
Value of redeemable members' interest			$65.10
Contribution to initial public offering	28,571,429
Class B Units [Member] | Initial Public Offering [Member]
Equity [Line Items]
Member's equity, units issued	71,428,571

Employee_Benefit_Plan_Addition

Employee Benefit Plan - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
	Pension_Plan
Defined Benefit Plan Disclosure [Line Items]
Company contributions to the plan	$600,000	$500,000	$400,000
Number of noncontributory defined benefit pension plans	2
Effective date of plan	1-Jan-14
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan fair value of investments	0	0
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation	63.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation	30.00%
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
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
Expected contribution to plans	$1,000,000

Employee_Benefit_Plans_Changes

Employee Benefit Plans - Changes in Projected Benefit Obligations Fair Value of Plan Assets and Funded Status of Plan (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
Change in fair value of plan assets:
Current liabilities	($1,041)	($1,268)
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:
Fair value of assets at 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
Fair value of assets at 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_Schedul

Employee Benefit Plans - Schedule of Net Periodic Pension Benefit Cost and Other Comprehensive Income (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
Amounts recognized in other comprehensive loss (income):
Curtailment benefit	($1,346)
Total amount recognized	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) loss	-117	-387	-261
Total amount recognized	4,533	-3,225	2,183
Components of net periodic benefit cost:
Service cost	75	295	276
Interest cost	1,081	963	1,055
Amortization of (gain) 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]
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) loss	-227	-314	-312
Total amount recognized	732	-1,182	1,465
Components of net periodic benefit cost:
Service cost	106	236	207
Interest cost	493	513	585
Amortization of (gain) loss	227	314	312
Expected return on plan assets			-180
Curtailment benefits	-1,346
Special termination benefits		39
Amortization of prior service credit	-174	-180
Net periodic benefit cost	($694)	$922	$924

Employee_Benefit_Plans_Weighte

Employee Benefit Plans - Weighted-Average Assumptions Used to Determine Benefit Obligations (Detail)	Dec. 27, 2014	Dec. 28, 2013
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets	7.30%	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_Weighte1

Employee Benefit Plans - Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost (Detail)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets	7.50%	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_Effects

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

Employee_Benefit_Plans_Fair_Va

Employee Benefit Plans - Fair Value of Company's Pension Plans' Assets (Detail) (Pension Benefits [Member], USD $)	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Defined Benefit Plan Disclosure [Line Items]
Total fair value	$18,872	$19,074	$17,863
Fixed Income Securities [Member] | Intermediate - Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	1,468	1,647
Fixed Income Securities [Member] | Intermediate - Corporate [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	3,342	3,138
Fixed Income Securities [Member] | Short-Term - Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	2,435	2,168
Fixed Income Securities [Member] | Short-Term - Corporate [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	3,700	4,040
Equity Securities [Member] | U.S. Large Cap Value [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	1,180	1,221
Equity Securities [Member] | U.S. Large Cap Growth [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	1,173	1,536
Equity Securities [Member] | U.S. Mid Cap Value [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	590	600
Equity Securities [Member] | U.S. Mid Cap Growth [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	598	603
Equity Securities [Member] | U.S. Small Cap Value [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	597	610
Equity Securities [Member] | U.S. Small Cap Growth [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	611	599
Equity Securities [Member] | International [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	1,098	889
Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	1,712	1,665
Precious Metals [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	368	358
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	7,927	8,081
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities [Member] | U.S. Large Cap Value [Member]
Defined Benefit Plan Disclosure [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]
Defined Benefit Plan Disclosure [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]
Defined Benefit Plan Disclosure [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]
Defined Benefit Plan Disclosure [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]
Defined Benefit Plan Disclosure [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]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	611	599
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Securities [Member] | International [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	1,098	889
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	1,712	1,665
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Precious Metals [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	368	358
Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	10,945	10,993
Observable Inputs (Level 2) [Member] | Fixed Income Securities [Member] | Intermediate - Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	1,468	1,647
Observable Inputs (Level 2) [Member] | Fixed Income Securities [Member] | Intermediate - Corporate [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	3,342	3,138
Observable Inputs (Level 2) [Member] | Fixed Income Securities [Member] | Short-Term - Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	2,435	2,168
Observable Inputs (Level 2) [Member] | Fixed Income Securities [Member] | Short-Term - Corporate [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	$3,700	$4,040

Employee_Benefit_Plans_Estimat

Employee Benefit Plans - Estimated Benefit Payments (Detail) (USD $)	Dec. 27, 2014
In Thousands, unless otherwise specified
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
2015	$1,715
2016	1,743
2017	1,740
2018	1,773
2019	1,777
2020 - 2024	8,524
Total	17,272
Healthcare & Life Ins. [Member]
Defined Benefit Plan Disclosure [Line Items]
2015	1,041
2016	1,015
2017	893
2018	893
2019	823
2020 - 2024	3,912
Total	$8,577

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013
Maximum [Member]
Commitment And Contingencies [Line Items]
Purchase commitment period	1 year
Sunken Barge [Member]
Commitment And Contingencies [Line Items]
Accrued costs to remove barge	0.4	$0.90

RelatedParty_Transactions_Addi

Related-Party Transactions - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012	Dec. 31, 2011
Related Party Transaction [Line Items]
Sales to related parties	$18,775,000	$16,578,000	$16,303,000
Accounts receivables due from related parties	1,470,000	422,000
Accrued interest due to non-controlling interest		723,000
Non-controlling [Member]
Related Party Transaction [Line Items]
Sales to related parties	14,300,000	12,700,000	12,500,000
Accounts receivables due from related parties	1,200,000	200,000
Accrued interest due to non-controlling interest		700,000
Purchased equipment				2,300,000
Summit Materials [Member]
Related Party Transaction [Line Items]
Sales to related parties	4,500,000	4,500,000	3,800,000
Accounts receivables due from related parties	$300,000	$200,000

Leasing_Arrangements_Additiona

Leasing Arrangements - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
Leases [Abstract]
Rent expense, including short-term rentals	$0.40	$0.40	$0.50

Leasing_Arrangements_Minimum_R

Leasing Arrangements - Minimum Rental Commitments under Long-Term Operating and Capital Leases (Detail) (USD $)	Dec. 27, 2014
In Thousands, unless otherwise specified
Leases [Abstract]
2015	$132
2016	115
2017	79
2018	76
2019	73
2015	334
2016	328
2017	328
2018	328
2019	$328

Supplementary_Data_Unaudited_Q

Supplementary Data (Unaudited) - Quarterly Supplemental Financial Information (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 27, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 28, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 27, 2014	Dec. 28, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Revenues	$29,446	$38,168	$31,822	$10,628	$22,509	$34,155	$27,224	$12,361	$110,064	$96,249	$94,882
Operating income (loss)	8,876	6,920	9,201	-5,291	9,259	10,965	9,053	-8,449	19,706	20,828	19,378
Net income (loss)	$6,034	$3,964	$6,180	($8,153)	$6,668	$8,157	$6,272	($11,232)	$8,025	$9,865	$6,625