Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Assump) (Details)

v3.8.0.1
Stock-Based Compensation (Assump) (Details) - $ / shares
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Summary of weighted average assumptions used to value options granted      
Grant date fair value of options (in dollars per share) $ 14.46 $ 14.51 $ 9.56
Volatility (as a percent) 42.20% 43.80% 42.20%
Risk-free interest rate (as a percent) 1.10% 2.10% 1.40%
Expected term (in years) 5 years 6 years 3 months 18 days 6 years 3 months 18 days