Partners' Capital of Mid-America Apartments, L.P. (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Schedule of Capital Structure [Line Items]
Operating partnership units outstanding	117,823,412	79,683,089
General Partners' Capital Account, Units Outstanding	113,607,734	75,524,086
Limited Liability (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	0.9642203707
Percentage Of Ownership Interests	100.00%
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest		94.80%
Limited Partners' Capital Account, Units Outstanding	4,215,678
Noncontrolling Interest [Member]
Schedule of Capital Structure [Line Items]
Common Shares Issuable Upon Conversion Of Convertible Stock	4,215,678	4,159,003
Limited Partners' Capital Account	$ 444.2	$ 442.5
Redeemable Capital Shares Par Or Stated Value Per Share	$ 105.38	$ 106.40