Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Consolidated Balance Sheets
Receivables, allowance for doubtful accounts	$ 9,842	$ 10,084
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	160,000,000us-gaap_CommonStockSharesAuthorized	160,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	95,065,638us-gaap_CommonStockSharesIssued	95,065,638us-gaap_CommonStockSharesIssued
Common stock, shares outstanding	57,587,566us-gaap_CommonStockSharesOutstanding	57,337,720us-gaap_CommonStockSharesOutstanding
Treasury stock, shares	37,478,072us-gaap_TreasuryStockShares	37,727,918us-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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