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Stock-Based Compensation (Schedule Of Assumptions To Calculate The Estimated Fair Value Of The Awards) (Details)
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12 Months Ended | ||
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Dec. 31, 2011
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Dec. 31, 2010
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Dec. 31, 2009
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| Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | |||
| Expected dividend yield | 0.00% | 0.00% | 0.00% |
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Stock Options [Member]
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| Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | |||
| Expected volatility | 29.00% | 31.00% | 35.00% |
| Expected term in years | 5.6 | 5.4 | 5.3 |
| Risk-free interest rate | 2.20% | 2.30% | 2.10% |
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ESPP [Member]
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| Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | |||
| Expected volatility | 30.00% | 35.00% | 37.00% |
| Expected term in years | 1.4 | 1.3 | 1.3 |
| Risk-free interest rate | 0.80% | 0.40% | 0.70% |