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Equity-Based Compensation (Weighted-Average Assumptions Used For Employee Grants Of Stock Options And SARs) (Details) (USD $)
12 Months Ended
Dec. 31, 2011
years
Dec. 31, 2010
years
Dec. 31, 2009
years
Expected dividend yield 0.00% 0.00% 0.00%
Forfeiture rate 11.50% 9.78% 9.92%
Risk free interest rate, minimum 0.01% 0.06% 0.15%
Risk free interest rate, maximum 3.18% 3.41% 3.29%
Expected weighted-average life, in years 5.42 5.36 5.23
Fair value of options and SARs granted $ 5,495,000 $ 6,527,000 $ 6,046,000
Weighted-average grant date fair value of options and SARs granted (per underlying share) $ 14.29 $ 10.64 $ 8.06
Stock Option And Stock Appreciation Rights (SARs) [Member]
     
Volatility 35.33% 39.50% 43.08%
Risk free interest rate 2.01% 2.26% 2.23%