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Shareholders' Equity of MAA - Additional Information (Details) - USD ($) $ in Millions | 9 Months Ended |
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Dec. 31, 2019
Equity [Line Items] |  |  |
Common stock, shares outstanding | 114,369,812 | 114,065,859 | 114,246,393
Total common shares and operating partnership units outstanding | 118,428,070 | 118,140,136 |
Proceeds from Stock Options Exercised, Net | $ 0.1 | $ 1.0 |
At The Market Offering |  |  |
Equity [Line Items] |  |  |
Common stock shares sold | 0 | 0 |
Remaining common stock to be issued | 3,900,000 |  |
Maximum [Member] | At The Market Offering |  |  |
Equity [Line Items] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 4,000,000.0 |  |
Equity Option |  |  |
Equity [Line Items] |  |  |
Stock Issued During Period, Shares, New Issues | 918 | 24,256 |
Noncontrolling Interest |  |  |
Equity [Line Items] |  |  |
Common Shares Issuable Upon Conversion Of Convertible Stock | 4,058,258 | 4,074,277 |
Employee Stock Option |  |  |
Equity [Line Items] |  |  |
Common stock shares, outstanding option | 19,845 | 45,390 |

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