Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Consolidated Balance Sheets [Abstract]
Allowance for doubtful accounts, accounts receivable	$ 2,918	$ 2,943
Accumulated Depreciation Depletion And Amortization Property Plant And Equipment	$ 369,128	$ 362,620
Preferred shares, par value	$ 0.1	$ 0.1
Preferred shares, shares authorized	5,000us-gaap_PreferredStockSharesAuthorized	5,000us-gaap_PreferredStockSharesAuthorized
Preferred shares, issued	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Common shares, par value	$ 0.1	$ 0.1
Common shares, shares authorized	145,000us-gaap_CommonStockSharesAuthorized	145,000us-gaap_CommonStockSharesAuthorized
Common shares, issued	52,478us-gaap_CommonStockSharesIssued	52,994us-gaap_CommonStockSharesIssued
Common shares, outstanding	52,478us-gaap_CommonStockSharesOutstanding	52,994us-gaap_CommonStockSharesOutstanding

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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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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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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