Stock-Based Compensation - Compensation Expense (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Total equity based compensation expense $ 3,825 $ 9,420
Restricted stock awards    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Total equity based compensation expense 1,490 3,364
Stock option awards    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Total equity based compensation expense 2,104 5,825
Performance stock units    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Total equity based compensation expense $ 231 $ 231