Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 28, 2015	Dec. 27, 2014
Allowance on trade accounts receivable	$ 4,248	$ 4,338
Allowance on other receivables	4,235	4,189
Accumulated depreciation and amortization on operating property	$ 165,007	$ 160,681
Common stock, par value	$ 0.01	$ 0.01
Common stock, authorized shares	160,000,000us-gaap_CommonStockSharesAuthorized	160,000,000us-gaap_CommonStockSharesAuthorized
Common stock, issued shares	67,349,642us-gaap_CommonStockSharesIssued	67,268,817us-gaap_CommonStockSharesIssued
Treasury stock, shares	22,938,800us-gaap_TreasuryStockShares	22,474,331us-gaap_TreasuryStockShares

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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The valuation allowance as of the balance sheet date to reduce the gross amount of receivables to estimated net realizable value, which would be presented in parentheses on the face of the balance sheet.

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A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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Face amount or stated value per share of common stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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