v2.4.0.8
Stock-Based Compensation (Asummptions used to estimate fair value for options) (Details) (USD $)
9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term 6 years 6 months [1] 6 years 6 months [1]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate 1.40% [2]  
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate 25.60% [3]  
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate 0.00% [4] 0.00% [4]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value $ 5.31 $ 5.18
Minimum [Member]
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate   1.20%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate   27.00% [3]
Maximum [Member]
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate   1.60%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate   30.50% [3]
[1] Expected term calculated using the simplified method prescribed by the SEC due to the lack of sufficient historical exercise data to provide a reasonable basis to estimate the expected term.
[2] Zero Coupon U.S. Treasury rate or equivalent based on expected term.
[3] Volatility calculated using the implied volatility of our exchange traded stock options.
[4] We have never paid cash dividends on our common stock, and we do not anticipate any cash dividend payments on our common stock in the near future.