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Stock-Based Compensation And Employee Benefit Plans (Weighted-Average Assumptions For Option Awards Granted) (Details) (Employee Stock Option [Member])
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Employee Stock Option [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate, minimum 0.80% 1.10% 1.60%
Risk-free interest rate, maximum 2.50% 3.10% 3.20%
Risk-free interest rate, weighted average 1.40% 2.10% 2.60%
Expected term (in years), minimum 5.2 5.3 5.4
Expected term (in years), maximum 6.8 8.0 5.9
Expected term (in years),weighted average 5.7 5.90 5.90
Expected volatility, minimum 34.00% 34.00% 36.00%
Expected volatility, maximum 36.00% 37.00% 40.00%
Expected volatility, weighted average 34.00% 35.00% 38.00%
Expected dividend yield 0.00% 0.00% 0.00%
Expected dividend yield, Weighted Average 0.00% 0.00% 0.00%