Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Trade Accounts receivable, allowances	$ 5,497	$ 5,717
Common Stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000us-gaap_CommonStockSharesAuthorized	200,000,000us-gaap_CommonStockSharesAuthorized
Common Stock shares issued	87,556,248us-gaap_CommonStockSharesIssued	87,556,248us-gaap_CommonStockSharesIssued
Common Stock, shares outstanding	63,203,361us-gaap_CommonStockSharesOutstanding	63,415,444us-gaap_CommonStockSharesOutstanding
Treasury stock, shares	24,352,887us-gaap_TreasuryStockShares	24,140,804us-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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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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