Share-Based Compensation and Cash-Based Incentive Compensation - Outstanding Restricted Shares Issued to Non-employee Directors (Details) - Restricted Shares - shares |
Jun. 30, 2018 |
Dec. 31, 2017 |
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| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
| Awards expected to vest by period | 181,832 | 246,528 |
| 2019 | ||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
| Awards expected to vest by period | 105,012 | |
| 2020 | ||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
| Awards expected to vest by period | 62,972 | |
| 2021 | ||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | ||
| Awards expected to vest by period | 13,848 |
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- Definition The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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