Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Options) (Details)

v3.8.0.1
Stock-Based Compensation (Options) (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Sep. 30, 2017
Dec. 31, 2016
Weighted-Average Remaining Contractual Life          
Outstanding 4 years 1 month 6 days   4 years 6 months    
Aggregate Intrinsic Value          
Outstanding (in dollars) $ 89,739     $ 89,739  
Stock options          
Options          
Outstanding at the beginning of the period (in shares) 2,804,420 2,891,036 3,033,194 3,033,194  
Granted (in shares)     75,238    
Exercised (in shares) (134,890) (84,949) (208,334)    
Forfeited (in shares) (2,201) (1,667) (9,062)    
Outstanding at the end of the period (in shares) 2,667,329 2,804,420 2,891,036 2,667,329 3,033,194
Options exercisable (in shares) 2,435,815     2,435,815  
Weighted-Average Exercise Price          
Outstanding at the beginning of the period (in dollars per share) $ 17.41 $ 17.15 $ 16.33 $ 16.33  
Granted (in dollars per share)     31.70    
Exercised (in dollars per share) 13.71 8.46 9.12    
Forfeited (in dollars per share) 30.33 32.46 45.81    
Outstanding at the end of the period (in dollars per share) 17.58 $ 17.41 $ 17.15 17.58 $ 16.33
Options exercisable (in dollars per share) $ 16.11     $ 16.11  
Weighted-Average Remaining Contractual Life          
Outstanding   4 years 3 months 18 days     4 years 3 months 18 days
Options exercisable 3 years 8 months 12 days        
Aggregate Intrinsic Value          
Outstanding (in dollars)   $ 66,206 $ 50,792   $ 63,264
Options exercisable (in dollars) $ 85,448     $ 85,448  
Additional disclosures          
Unrecognized stock-based compensation expense related to unvested stock options $ 2,414     $ 2,414  
Unrecognized compensation expense weighted-average recognition period       1 year 9 months 18 days  
Stock options | Minimum          
Additional disclosures          
Exercise prices of stock options outstanding (in dollars per share) $ 0.11     $ 0.11  
Stock options | Maximum          
Additional disclosures          
Exercise prices of stock options outstanding (in dollars per share) $ 55.29     $ 55.29