Properties, Net (Details) - USD ($) $ in Thousands  | 
Sep. 30, 2018  | 
Dec. 31, 2017  | 
|---|---|---|
| Investments in real estate | ||
| Operating properties, net | $ 2,796,577 | $ 2,737,611 | 
| Operating Properties | ||
| Investments in real estate | ||
| Less: accumulated depreciation | (867,659) | (786,193) | 
| Operating properties, net | 2,796,577 | 2,737,611 | 
| Operating Properties | Land | ||
| Investments in real estate | ||
| Gross | 481,527 | 455,680 | 
| Operating Properties | Buildings and improvements | ||
| Investments in real estate | ||
| Gross | $ 3,182,709 | $ 3,068,124 | 
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- Definition Amount, before accumulated depreciation, of real estate investments for entities with a substantial portion of business acquiring and holding investment real estate. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition The cumulative amount of depreciation for real estate property held for investment purposes. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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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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- Definition Carrying amount of income producing properties held for rental. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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