| Stock-Based Compensation - Vested and unvested LTIP units (Details) shares in Thousands | 9 Months Ended | 
|---|---|
| Sep. 30, 2019  shares | |
| Total vested units | 483 | 
| Unvested units: | |
| Total unvested units | 308 | 
| LTIP units outstanding as of December 31, 2018 | 791 | 
| Advisor [Member] | |
| Unvested units: | |
| Granted | 286 | 
| Independent directors [Member] | |
| Unvested units: | |
| Granted | 22 | 
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- Definition Number of equity instruments other than options outstanding, including both vested and non-vested instruments. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Gross number of share options (or share units) granted during the period. No definition available. 
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- Definition Number of non-vested options outstanding. No definition available. 
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available. 
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- Definition Number of options vested. No definition available. 
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- Details 
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- Details 
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