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Summary of Significant Accounting Policies - Additional Information (Details) | 12 Months Ended
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Dec. 31, 2018 USD ($) Property ApartmentUnit $ / shares | Dec. 31, 2017 USD ($) $ / shares | Dec. 31, 2016 USD ($) $ / shares
Value of furniture and fixtures minimum range | $ 10,000 |  |
Value of furniture and fixtures maximum range | $ 35,000 |  |
Lease intangibles, average term | 6 months |  |
Capitalized costs development and renovation | $ 13,200,000 | $ 14,700,000 | $ 18,700,000
Common Stock, Par or Stated Value Per Share | $ / shares | $ 0.01 | $ 0.01 | $ 0.01
Land and depreciable property net | $ 14,000,000,000 | $ 14,800,000,000 |
Discount rate description | The discount rates were determined using the Company’s borrowing rates (actual pricing through 30 years and other long-term market rates). |  |
Percentage of rental income excluded from accounting standard adoption | 94.00% |  |
Percentage of total revenue subject to revenue recognition standard | 6.00% |  |
Properties | Property | 307 |  |
Noncontrolling Interests – Partially Owned Properties | $ (2,293,000) | $ 4,708,000 |
Apartment units | ApartmentUnit | 79,482 |  |
Partially Owned Properties – Consolidated |  |  |
Properties | Property | 17 |  |
Noncontrolling Interests – Partially Owned Properties | $ 2,300,000 |  |
Apartment units | ApartmentUnit | 3,535 |  |
Limited Life Partnership Properties [Member] |  |  |
Properties | Property | 4 |  |
Noncontrolling Interests – Partially Owned Properties | $ 9,600,000 |  |
Noncontrolling interests settlement value | 70,400,000 |  |
Accounting Standards Update 2016-02 [Member] |  |  |
Expected right of use assets and related lease liabilities to opening balance sheet adoption of new accounting standard on leases | $ 300,000,000 |  |
Minimum [Member] | Retail Commercial Leases [Member] |  |  |
Retail/commercial leases term | 5 years |  |
Minimum [Member] | Corporate Office Leases [Member] |  |  |
Discount rate | 3.30% |  |
Minimum [Member] | Ground Leases [Member] |  |  |
Discount rate | 4.40% |  |
Maximum [Member] | Retail Commercial Leases [Member] |  |  |
Retail/commercial leases term | 10 years |  |
Maximum [Member] | Corporate Office Leases [Member] |  |  |
Discount rate | 3.90% |  |
Maximum [Member] | Ground Leases [Member] |  |  |
Discount rate | 5.50% |  |
Furniture and Fixtures [Member] | Minimum [Member] |  |  |
Property, plant and equipment, estimated useful lives | 5 years |  |
Furniture and Fixtures [Member] | Maximum [Member] |  |  |
Property, plant and equipment, estimated useful lives | 10 years |  |
Building [Member] |  |  |
Property, plant and equipment, estimated useful lives | 30 years |  |
Building Improvements [Member] |  |  |
Property, plant and equipment, estimated useful lives | 8 years |  |
Replacements [Member] | Minimum [Member] |  |  |
Property, plant and equipment, estimated useful lives | 5 years |  |
Replacements [Member] | Maximum [Member] |  |  |
Property, plant and equipment, estimated useful lives | 10 years |  |
Renovations and Improvements Minimum [Member] | Minimum [Member] |  |  |
Property, plant and equipment, estimated useful lives | 5 years |  |
Renovations and Improvements Minimum [Member] | Maximum [Member] |  |  |
Property, plant and equipment, estimated useful lives | 15 years |  |

X
- Definition Represents payroll and associated costs of employees directly responsible for and who spend their time on the supervision of development activities as well as major capital and/or renovation projects that are capitalized on the balance sheet + References No definition available. + Details
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- Definition Represents the value of Noncontrolling Interest distributions had the Company's partnership agreements been liquidated through the sale of their assets upon reaching the date specified in each respective partnership agreement. The Company, as controlling partner, has an obligation to cause the property owning partnerships to distribute the proceeds of liquidation to the Noncontrolling Interests in these Partially Owned Properties. + References No definition available. + Details
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