Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation - Expense (Details)

v3.8.0.1
Share-Based Compensation - Expense (Details) - USD ($)
$ in Thousands, shares in Millions
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Share-Based Compensation    
Share-based compensation expense $ 2,402 $ 2,084
Income tax benefit realized from award vestings $ 2,614 $ 828
2015 Plan    
Share-Based Compensation    
Number of shares authorized 4.0  
Number of shares available 2.6