CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Trade accounts receivable, allowances	$ 6,515	$ 6,184
Preferred Stock, par value (in dollars per share)	$ 0us-gaap_PreferredStockNoParValue	$ 0us-gaap_PreferredStockNoParValue
Preferred Stock, authorized shares (in shares)	15,000,000us-gaap_PreferredStockSharesAuthorized	15,000,000us-gaap_PreferredStockSharesAuthorized
Preferred Stock, outstanding (in shares)	0us-gaap_PreferredStockSharesOutstanding	0us-gaap_PreferredStockSharesOutstanding
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	60,000,000us-gaap_CommonStockSharesAuthorized	60,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued (in shares)	41,755,000us-gaap_CommonStockSharesIssued	41,644,000us-gaap_CommonStockSharesIssued
Treasury stock, shares (in shares)	8,903,000us-gaap_TreasuryStockShares	8,903,000us-gaap_TreasuryStockShares

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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Face amount per share of no-par value preferred stock nonredeemable or redeemable solely at the option of the issuer.

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The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

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Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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