Quarterly report pursuant to Section 13 or 15(d)

Share-Based Payments - Stock Option Activity (Details)

v3.19.1
Share-Based Payments - Stock Option Activity (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation expense $ 3,047 $ 2,261
Employee Stock Option [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock option grants expire (in years) 7 years  
Grants, vesting period (in years) 3 years  
Outstanding, beginning of period (in shares) 538  
Exercised (in shares) (18)  
Outstanding, end of period (in shares) 520  
Exercisable, end of period (in shares) 308  
Outstanding, beginning of period (in dollars per share) $ 51  
Exercises in Period (in dollars per share) 46  
Outstanding, end of period (in dollars per share) 52  
Exercisable, end of period (in dollars per share) $ 46  
Aggregate Intrinsic Value Outstanding, end of period $ 5,031  
Aggregate Intrinsic Value Exercisable, end of period $ 4,598  
Weighted-average remaining contractual term Outstanding, end of period (in years) 4 years 6 months 11 days  
Weighted-average remaining contractual term Exercisable, end of period (in years) 3 years 6 months 11 days  
Share-based compensation expense $ 439 342
Tax benefit related to share-based expense 105 88
Unrecognized share-based compensation, net of estimated forfeitures $ 2,768 $ 2,589
Weighted average period over which unrecognized compensation will be recognized (years) 1 year 10 months 11 days