Properties, Net (Details 2) - USD ($) $ in Thousands  | 
Sep. 30, 2016  | 
Dec. 31, 2015  | 
|---|---|---|
| Properties | ||
| Projects in development or held for future development | $ 396,269 | $ 429,219 | 
| Projects in development or held for future development | Land in development or held for future development | ||
| Properties | ||
| Projects in development or held for future development | 199,038 | 207,774 | 
| Projects in development or held for future development | Construction in progress, excluding land | ||
| Properties | ||
| Projects in development or held for future development | $ 197,231 | $ 221,445 | 
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- Definition The current amount of expenditures for a real estate project that has not yet been completed. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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