Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation Plans and Awards - Stock Options Narrative (Details)

v3.8.0.1
Stock-based Compensation Plans and Awards - Stock Options Narrative (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock-based compensation expense $ 26,436 $ 29,618
Stock options    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock-based compensation expense $ 700 $ 1,900