Share Based Compensation (Details) - Restricted shares - $ / shares |
3 Months Ended | 6 Months Ended | |
|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2019 |
Jun. 30, 2018 |
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Total number of restricted shares granted | 477,284 | 995,669 | 1,694,941 |
| Estimated fair value (in dollars per share) | $ 17.17 | $ 16.02 | $ 14.24 |
| Vested (in shares) | 4,360 | 43,996 | 33,028 |
| Vest over three years | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Total number of restricted shares granted | 472,924 | ||
| Vesting period from grant date | 3 years | ||