Share Based Compensation (Details)
3 Months Ended 6 Months Ended
Jun. 08, 2018
item
shares
Jan. 01, 2018
item
shares
Jun. 30, 2018
shares
Jun. 30, 2018
shares
Jun. 30, 2017
shares
Restricted shares          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total Number of restricted shares granted       1,694,941 502,981
Stock options          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Granted (in shares)       359,618 447,795
2013 Plan | Restricted shares          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total Number of restricted shares granted   1,678,743      
2013 Plan | Restricted shares | Time-vested and performance-vested          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total Number of restricted shares granted   1,609,857      
2013 Plan | Restricted shares | Vesting based on time          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Percentage of share instruments issued   50.00%      
2013 Plan | Restricted shares | Vesting based on time | Minimum          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Service based vesting period of awards   3 years      
2013 Plan | Restricted shares | Vesting based on time | Maximum          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Service based vesting period of awards   5 years      
2013 Plan | Restricted shares | Vesting based on performance          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Percentage of share instruments issued   50.00%      
Vesting installments | item   3      
2013 Plan | Restricted shares remaining | Vesting based on service          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total Number of restricted shares granted   68,886      
Service based vesting period of awards   4 years      
2013 Plan | Stock options          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total Number of options granted   357,256      
2013 Plan | Stock options | Vesting based on performance          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting percentage   40.00%      
2013 Plan | Stock options | Vesting based on service          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting percentage   60.00%      
Service based vesting period of awards   4 years      
2018 Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of shares authorized     3,372,484 3,372,484  
2018 Plan | Restricted shares          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total Number of restricted shares granted     16,198 16,198  
2018 Plan | Stock options          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total Number of options granted     2,362    
2018 Plan | Stock options | Vesting based on performance          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting percentage     50.00%    
2018 Plan | Stock options | Vesting based on service          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting percentage     50.00%    
Service based vesting period of awards     3 years    
2018 Plan | Employee Stock Purchase Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of shares authorized 350,388        
Term of the offering period 18 months        
Number of offering periods | item 3        
Term of individual offering periods 6 months        
Term established for purchasing stock under the employee stock purchase plan 3 months        
Discount percentage 5.00%        
Number of times a participant may make change or withdrawal from plan during a term | item 1