Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Summary of Stock-Based Compensation Activity - Stock Options) (Details)

v3.10.0.1
Stock-Based Compensation (Summary of Stock-Based Compensation Activity - Stock Options) (Details)
$ / shares in Units, $ in Thousands
9 Months Ended
Sep. 30, 2018
USD ($)
$ / shares
shares
Shares  
Outstanding at December 31, 2017 | shares 274,110
Exercised | shares (25,745)
Forfeited | shares (1,043)
Outstanding at September 30, 2018 | shares 247,322
Exercisable at September 30, 2018 | shares 245,977
Weighted Average Exercise Price  
Outstanding at December 31, 2017 | $ / shares $ 19.54
Exercised | $ / shares 17.64
Forfeited | $ / shares 31.59
Outstanding at September 30, 2018 | $ / shares 19.69
Exercisable at September 30, 2018 | $ / shares $ 19.63
Weighted Average Remaining Contractual Term (Years)  
Outstanding at September 30, 2018 3 years 5 months 9 days
Exercisable at September 30, 2018 3 years 5 months 5 days
Aggregate Intrinsic Value  
Outstanding at September 30, 2018 | $ $ 1,907
Exercisable at September 30, 2018 | $ $ 1,906