Shareholders' Equity of MAA - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended
	Aug. 31, 2021	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Equity [Line Items]
Common stock, shares outstanding		115,138,323	115,138,323	114,369,812	114,373,727
Total common shares and operating partnership units outstanding		118,541,005	118,541,005	118,428,070
Proceeds from Stock Options Exercised, Net			$ 1.5	$ 0.1
Equity Forward Sale Agreements [Member]
Equity [Line Items]
Stock Issued During Period, Shares, New Issues	1,100,000
Common stock, price per share	$ 190.56
Common stock settlement under agreement	0
Common shares attributable to dilutive effect of equity forward agreements		0	0
Equity Option [Member]
Equity [Line Items]
Stock Issued During Period, Shares, New Issues			19,032	918
Noncontrolling Interest [Member]
Equity [Line Items]
Common Shares Issuable Upon Conversion Of Convertible Stock		3,402,682	3,402,682	4,058,258
Employee Stock Option [Member]
Equity [Line Items]
Common stock shares, outstanding option		813	813	19,845