Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Options) (Details)

v3.10.0.1
Stock-Based Compensation (Options) (Details) - Stock options - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2018
Mar. 31, 2018
Jun. 30, 2018
Dec. 31, 2017
Options        
Outstanding at the beginning of the period (in shares) 2,090,040 2,254,565 2,254,565  
Exercised (in shares) (12,166) (162,857)    
Forfeited (in shares)   (1,668)    
Outstanding at the end of the period (in shares) 2,077,874 2,090,040 2,077,874 2,254,565
Options exercisable (in shares) 1,975,716   1,975,716  
Weighted-Average Exercise Price        
Outstanding at the beginning of the period (in dollars per share) $ 19.57 $ 19.23 $ 19.23  
Exercised (in dollars per share) 11.42 14.76    
Forfeited (in dollars per share)   32.46    
Outstanding at the end of the period (in dollars per share) 19.62 $ 19.57 19.62 $ 19.23
Options exercisable (in dollars per share) $ 19.17   $ 19.17  
Weighted-Average Remaining Contractual Life        
Outstanding 3 years 10 months 24 days 4 years 1 month 6 days   4 years 3 months 18 days
Options exercisable 3 years 7 months 6 days      
Aggregate Intrinsic Value        
Outstanding (in dollars) $ 73,421 $ 78,859 $ 73,421 $ 69,939
Options exercisable (in dollars) 70,703   70,703  
Additional disclosures        
Unrecognized stock-based compensation expense related to unvested stock options $ 1,197   $ 1,197  
Unrecognized compensation expense weighted-average recognition period     1 year 4 months 24 days  
Minimum        
Additional disclosures        
Exercise prices of stock options outstanding (in dollars per share) $ 7.15   $ 7.15  
Maximum        
Additional disclosures        
Exercise prices of stock options outstanding (in dollars per share) $ 55.29   $ 55.29