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 receivables, allowances	$ 2,040	$ 2,028
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	15,000,000us-gaap_PreferredStockSharesAuthorized	15,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, shares issued	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Preferred stock, shares outstanding	0us-gaap_PreferredStockSharesOutstanding	0us-gaap_PreferredStockSharesOutstanding
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	250,000,000us-gaap_CommonStockSharesAuthorized	250,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	70,029,000us-gaap_CommonStockSharesIssued	69,480,000us-gaap_CommonStockSharesIssued
Treasury stock, shares	40,616,000us-gaap_TreasuryStockShares	35,751,000us-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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