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Business Combinations (Textual) (Details) |  | 12 Months Ended
--- | --- | ---
Dec. 01, 2016 USD ($) Communities properties $ / shares shares | Dec. 31, 2018 USD ($) shares | Dec. 31, 2017 USD ($) shares | Dec. 31, 2016 USD ($)
Business Acquisition [Line Items] |  |  |  |
Business Combinations, Other Consideration | $ 2,000,000 |  |  |
Business Combination, Merger and Integration Related Expenses |  |  | $ 20,000,000 | $ 40,800,000
Redeemable Preferred Stock [Member] |  |  |  |
Business Acquisition [Line Items] |  |  |  |
Embedded Derivative, Fair Value of Embedded Derivative Asset | 14.24 |  |  |
Mandatorily Redeemable Preferred Stock, Fair Value Disclosure | $ 77.02 |  |  |
Preferred Stock, Shares Outstanding | shares | 867,846 |  |  |
Unsecured Debt |  |  |  |
Business Acquisition [Line Items] |  |  |  |
Business Combination, Consideration Transferred, Other | $ 300,000,000 |  |  |
Line of Credit [Member] |  |  |  |
Business Acquisition [Line Items] |  |  |  |
Business Combination, Consideration Transferred, Other | $ 162,000,000 |  |  |
Parent Company [Member] |  |  |  |
Business Acquisition [Line Items] |  |  |  |
Common Stock, Conversion Basis |  | 0.71 |  |
Business Combination, Merger and Integration Related Expenses |  | $ 9,112,000 | $ 19,990,000 | $ 40,823,000
Preferred Stock, Shares Outstanding | shares |  | 867,846 | 867,846 |
Parent Company [Member] | Post [Member] [Domain] |  |  |  |
Business Acquisition [Line Items] |  |  |  |
Number of Apartment Communities Acquired in Real Estate Property | Communities | 61 |  |  |
Number of Commercial Properties Acquired in Real Estate Property | properties | 4 |  |  |
Acquired properties, purchase price | $ (4,006,586,000) |  |  |
Share Price | $ / shares | $ 91.41 |  |  |
Stock Issued During Period, Shares, Acquisitions | shares | 38,000,000 |  |  |
Noncontrolling Interest |  |  |  |
Business Acquisition [Line Items] |  |  |  |
Stock Issued During Period, Shares, Acquisitions | shares | 80,000 |  |  |
Business Combination, Separately Recognized Transactions [Domain] |  |  |  |
Business Acquisition [Line Items] |  |  |  |
Business Combination, Merger and Integration Related Expenses |  | $ 9,100,000 |  |

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