Annual report pursuant to Section 13 and 15(d)

Stock-based Compensation Plans and Awards - Schedule of assumptions used for estimating the per-share fair value of stock options (Details)

v3.6.0.2
Stock-based Compensation Plans and Awards - Schedule of assumptions used for estimating the per-share fair value of stock options (Details) - Black-Scholes option pricing model - Stock options
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected life (in years) 6 years 29 days 6 years 29 days
Risk-free interest rate, minimum (as a percent) 1.75% 1.71%
Risk-free interest rate, maximum (as a percent) 1.92% 1.93%
Expected volatility, minimum (as a percent) 49.00% 58.00%
Expected volatility, maximum (as a percent) 50.00% 59.00%
Expected dividend yield (as a percent) 0.00% 0.00%