CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Receivables, allowances	$ 4,806,000	$ 4,459,000
Other noncurrent assets at fair value	$ 33,800,000
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000us-gaap_PreferredStockSharesAuthorized	5,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, shares issued	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Common stock, par value	$ 0.005	$ 0.005
Common stock, shares authorized	280,000,000us-gaap_CommonStockSharesAuthorized	280,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	139,820,388us-gaap_CommonStockSharesIssued	139,820,388us-gaap_CommonStockSharesIssued
Treasury stock, shares	24,182,584us-gaap_TreasuryStockShares	23,255,421us-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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Equity securities categorized neither as held-to-maturity nor trading which are intended be sold more than one year from the balance sheet date or operating cycle, if longer.

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Face amount or stated value per share of common stock.

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