Properties, Net (Details 2) - USD ($) $ in Thousands  | 
Jun. 30, 2019  | 
Dec. 31, 2018  | 
|---|---|---|
| Properties | ||
| Projects in development or held for future development | $ 474,787 | $ 403,361 | 
| Projects in development or held for future development | ||
| Properties | ||
| Projects in development or held for future development | 474,787 | 403,361 | 
| Projects in development or held for future development | Land | ||
| Properties | ||
| Projects in development or held for future development | 296,809 | 207,760 | 
| Projects in development or held for future development | Development in progress, excluding land | ||
| Properties | ||
| Projects in development or held for future development | $ 177,978 | $ 195,601 | 
| X | ||||||||||
- Definition The current amount of expenditures for a real estate project that has not yet been completed. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
  | 
| X | ||||||||||
- 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. 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
  |