| CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) (USD $) In Thousands, unless otherwise specified | Sep. 30, 2012 | Dec. 31, 2011 | 
|---|---|---|
| Current assets | ||
| Allowance for doubtful accounts | $ 13,947 | $ 16,986 | 
| X | ||||||||||
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- Definition 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. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Details 
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