Share Based Compensation (Details)
3 Months Ended 9 Months Ended
Jun. 08, 2018
USD ($)
item
shares
Sep. 30, 2018
shares
Sep. 30, 2018
shares
Sep. 30, 2017
shares
Jul. 31, 2018
shares
Restricted shares          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total number of restricted shares granted     1,904,595 623,165  
Vested (in shares)     (209,765) (339,701)  
Stock options          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Granted (in shares)     359,618 774,357  
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   209,654 225,852    
Vested (in shares)   (6,771)      
2018 Plan | Restricted shares | Cliff vesting          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Total number of options granted   202,883      
Vesting percentage   100.00%      
Vesting period     3 years    
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]          
The number of share instruments with approved modifications of the vesting conditions         114,283
Director Plan | Restricted shares          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vested (in shares)       (49,230)  
2018 ESPP          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of shares authorized 350,388        
Number of shares issued     1,332    
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%        
Maximum dollar amount of shares that can be purchased by an individual in any given calendar year | $ $ 25,000        
Number of times a participant may make change or withdrawal from plan during a term | item 1