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Summary of Significant Accounting Policies - Additional Information (Details) | 1 Months Ended | 3 Months Ended | 6 Months Ended
--- | --- | --- | ---
Feb. 28, 2017 USD ($) | Jun. 30, 2018 USD ($) Property ApartmentUnit | Jun. 30, 2017 USD ($) | Jun. 30, 2018 USD ($) Property ApartmentUnit | Jun. 30, 2017 USD ($)
Provision for income tax |  | $ 274,000 | $ 220,000 | $ 487,000 | $ 482,000
Percentage of rental income excluded from accounting standard adoption |  |  |  | 94.00% |
Percentage of total revenue subject to revenue recognition standard |  |  |  | 6.00% |
Properties | Property |  | 304 |  | 304 |
Apartment Units | ApartmentUnit |  | 78,645 |  | 78,645 |
Noncontrolling interests equity (deficit) partially owned properties |  | $ 1,600,000 |  | $ 1,600,000 |
Partially Owned Properties – Consolidated |  |  |  |  |
Properties | Property |  | 17 |  | 17 |
Apartment Units | ApartmentUnit |  | 3,535 |  | 3,535 |
Limited Life Partnership Properties [Member] |  |  |  |  |
Properties | Property |  | 4 |  | 4 |
Noncontrolling interests equity (deficit) partially owned properties |  | $ 8,700,000 |  | $ 8,700,000 |
Noncontrolling interests settlement value |  | $ 66,800,000 |  | 66,800,000 |
Adjustments for New Accounting Principle, Early Adoption |  |  |  |  |
Gain (loss) on equity transaction | $ 0 |  |  |  |
Federal [Member] |  |  |  |  |
Provision for income tax |  |  |  | $ 0 |

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