| Amortization Period for Intangible Assets (Detail) | 9 Months Ended | 
|---|---|
| Sep. 30, 2012 | |
| Customer relationships | |
| Business Acquisition [Line Items] | |
| Remaining useful life | 10 years | 
| Developed technology | |
| Business Acquisition [Line Items] | |
| Remaining useful life | 10 years | 
| Trade names / Trademarks | |
| Business Acquisition [Line Items] | |
| Remaining useful life | 5 years | 
| Noncompete agreements | |
| Business Acquisition [Line Items] | |
| Remaining useful life | 4 years | 
| Goodwill | |
| Business Acquisition [Line Items] | |
| Useful life | Indefinite | 
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- Definition Intangible Assets Useful Life No definition available. 
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- Details 
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- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available. 
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