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Stock-Based Compensation Long-Term Performance Restricted Stock Unit Award Monte Carlo Pricing Model Assumptions (Details) (Restricted Stock Units (RSUs) [Member], USD $)
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3 Months Ended | 9 Months Ended | |||||||||
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Sep. 30, 2014
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Sep. 30, 2013
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Sep. 30, 2014
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Sep. 30, 2013
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||||||
| Weighted-average fair value | $ 35.64 | [1] | $ 42.51 | [1] | |||||||
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Long Term Performance Restricted Stock Award [Member]
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||||||
| Dividend yield | 0.00% | 0.00% | [2] | 0.00% | 0.00% | ||||||
| Expected volatility | 30.10% | 0.00% | [2] | 32.30% | 39.10% | ||||||
| Risk-free interest rate | 0.70% | 0.00% | [2] | 0.40% | 0.30% | ||||||
| Expected term (years) | 2 years 3 months 20 days | 0 years 0 months 1 day | [2] | 2 years 0 months 0 days | 2 years 6 months 10 days | ||||||
| Weighted-average fair value | $ 43.05 | $ 0.00 | [2] | $ 35.15 | $ 45.03 | ||||||
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