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

Deferred tax assets capital losses on securities.

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Deferred tax assets liabilities net before valuation allowances.

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Deferred tax assets mining reclamation reserve.

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Deferred tax assets working capital.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from inventory.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences expected to be realized or consumed within one year or operating cycle, if longer.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount of deferred tax liability attributable to taxable temporary differences net of deferred tax asset attributable to deductible temporary differences and carryforwards after valuation allowances.

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Amount of deferred tax liability attributable to taxable temporary differences from intangible assets other than goodwill.

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Amount of deferred tax liability attributable to taxable temporary differences, net of deferred tax asset attributable to deductible temporary differences and carryforwards net of valuation allowances expected to be realized or consumed after one year (or the normal operating cycle, if longer).

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Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment.

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