Annual report pursuant to Section 13 and 15(d)

Stock Compensation and Long Term Incentive Plans - Valuation Assumptions (Details)

v2.4.0.8
Stock Compensation and Long Term Incentive Plans - Valuation Assumptions (Details)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected term (in years)     4 years 4 months 24 days
Expected volatility, minimum (as a percent) 35.90% 37.50% 31.90%
Expected volatility, maximum (as a percent) 41.40% 54.20% 54.20%
Risk-free rate of return. minimum (as a percent) 0.70% 0.50% 0.70%
Risk-free rate of return, maximum (as a percent) 1.40% 1.00% 1.90%
Minimum
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected term (in years) 4 years 7 months 7 days 4 years 6 months  
Maximum
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected term (in years) 6 years 10 months 25 days 7 years 0 months 29 days