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Stock-Based Compensation - Narrative (Details) - USD ($) $ in Millions | 9 Months Ended | 114 Months Ended |  |  |
--- | --- | --- | --- | --- | ---
Sep. 30, 2020 | Jun. 30, 2020 | Dec. 31, 2019 | Feb. 28, 2018 | Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Granted (in shares) | 0 | 0 |  |  |
Restricted Shares and Performance Based Shares |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Unrecognized expense related to stock awards | $ 5.0 |  |  |  |
Period of time stock expense is expected to be recognized | 1 year 7 months 6 days |  |  |  |
Executive | Performance Shares |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Maximum number of shares awarded in year one (in shares) | 150,543 |  |  |  |
Maximum number of shares awarded in year two (in shares) | 142,080 |  |  |  |
Maximum number of shares awarded in year three (in shares) | 142,047 |  |  |  |
Performance period | 3 years |  |  |  |
Executive | Performance Shares | Achieved performance target for 2017 through 2019 |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Maximum number of shares awarded in year one (in shares) | 122,277 |  |  |  |
Chairman, President, and Chief Executive Officer | Achieves a specific performance target by the end of 2019 and she remains an employee | Common Stock |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Shares received if achieves specified improvement in total shareholders return (in shares) |  |  | 35,906 |  | 53,859
Chairman, President, and Chief Executive Officer | Achieves a specific performance target by the end of 2017 and she remains an employee | Common Stock |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Shares received if achieves specified improvement in total shareholders return (in shares) |  |  |  | 17,953 |
Performance Equity Plan |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Vesting period | 3 years |  |  |  |
Vesting rate | 100.00% |  |  |  |
Performance Equity Plan | Non-employee Members of the Board of Directors |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |
Vesting period | 1 year |  |  |  |

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