Partners' Capital of Mid-America Apartments, L.P.	3 Months Ended
Mar. 31, 2019
Partners' Capital of Mid-America Apartments, L.P. [Abstract]
Partners' Capital Notes Disclosure [Text Block]	Partners' Capital of MAALP Common units of limited partnership interests in MAALP are represented by OP Units. As of March 31, 2019, there were 118,021,379 OP Units outstanding, 113,916,208, or 96.5%, of which represent Class B OP Units (common units issued to or held by MAALP's general partner or any of its subsidiaries), which were owned by MAA, MAALP's general partner. The remaining 4,105,171 OP Units were Class A OP Units owned by Class A limited partners. As of March 31, 2018, there were 117,886,987 OP Units outstanding, 113,745,207, or 96.5%, of which were owned by MAA and 4,141,780 of which were owned by the Class A limited partners. MAA, as the sole general partner of MAALP, has full, complete and exclusive discretion to manage and control the business of MAALP subject to the restrictions specifically contained within MAALP's agreement of limited partnership, or the Partnership Agreement. Unless otherwise stated in the Partnership Agreement, this power includes, but is not limited to, acquiring, leasing, or disposing of any real property; constructing buildings and making other improvements to properties owned; borrowing money, modifying or extinguishing current borrowings, issuing evidence of indebtedness, and securing such indebtedness by mortgage, deed of trust, pledge or other lien on MAALP's assets; and distribution of MAALP's cash or other assets in accordance with the Partnership Agreement. MAA can generally, at its sole discretion, issue and redeem OP Units and determine the consideration to be received or the redemption price to be paid, as applicable. The general partner may delegate these and other powers granted if the general partner remains in supervision of the designee. Under the Partnership Agreement, MAALP may issue Class A OP Units and Class B OP Units. Class A OP Units are any OP Units other than Class B OP Units, while Class B OP Units are those issued to or held by MAALP's general partner or any of its subsidiaries. In general, the limited partners do not have the power to participate in the management or control of MAALP's business except in limited circumstances including changes in the general partner and protective rights if the general partner acts outside of the provisions provided in the Partnership Agreement. The transferability of Class A OP Units is also limited by the Partnership Agreement. Net income (after allocations to preferred ownership interests) is allocated to the general partner and limited partners based on their respective ownership percentages of MAALP. Issuance or redemption of additional Class A OP Units or Class B OP Units changes the relative ownership percentage of the partners. The issuance of Class B OP Units generally occurs when MAA issues common stock and the proceeds from that issuance are contributed to MAALP in exchange for the issuance to MAA of a number of OP Units equal to the number of shares of common stock issued. Likewise, if MAA repurchases or redeems outstanding shares of common stock, MAALP generally redeems an equal number of Class B OP Units with similar terms held by MAA for a redemption price equal to the purchase price of those shares of common stock. At each reporting period, the allocation between general partner capital and limited partner capital is adjusted to account for the change in the respective percentage ownership of the underlying capital of MAALP. Holders of the Class A OP Units may require MAA to redeem their Class A OP Units, in which case MAA may, at its option, pay the redemption price either in cash (in an amount per Class A OP Unit equal, in general, to the average closing price of MAA's common stock on the NYSE over a specified period prior to the redemption date) or by delivering one share of MAA common stock (subject to adjustment under specified circumstances) for each Class A OP Unit so redeemed. At March 31, 2019, a total of 4,105,171 Class A OP Units were outstanding and redeemable for 4,105,171 shares of MAA common stock, with an approximate value of $448.8 million, based on the closing price of MAA’s common stock on March 29, 2019 of $109.33 per share. At March 31, 2018, a total of 4,141,780 Class A OP Units were outstanding and redeemable for 4,141,780 shares of MAA common stock, with an approximate value of $377.9 million, based on the closing price of MAA’s common stock on March 29, 2018 of $91.24 per share. MAALP pays the same per unit distributions in respect to the OP Units as the per share dividends MAA pays in respect to its common stock. As of March 31, 2019, MAALP had one outstanding series of cumulative redeemable preferred units, or the MAALP Series I Preferred Units. The MAALP Series I Preferred Units have the same characteristics as the MAA Series I preferred stock described in Note 8. As of March 31, 2019, 867,846 units of the MAALP Series I Preferred Units were outstanding.

Partners' Capital of MAALP

Common units of limited partnership interests in MAALP are represented by OP Units. As of March 31, 2019, there were 118,021,379 OP Units outstanding, 113,916,208, or 96.5%, of which represent Class B OP Units (common units issued to or held by MAALP's general partner or any of its subsidiaries), which were owned by MAA, MAALP's general partner. The remaining 4,105,171 OP Units were Class A OP Units owned by Class A limited partners. As of March 31, 2018, there were 117,886,987 OP Units outstanding, 113,745,207, or 96.5%, of which were owned by MAA and 4,141,780 of which were owned by the Class A limited partners.

MAA, as the sole general partner of MAALP, has full, complete and exclusive discretion to manage and control the business of MAALP subject to the restrictions specifically contained within MAALP's agreement of limited partnership, or the Partnership Agreement. Unless otherwise stated in the Partnership Agreement, this power includes, but is not limited to, acquiring, leasing, or disposing of any real property; constructing buildings and making other improvements to properties owned; borrowing money, modifying or extinguishing current borrowings, issuing evidence of indebtedness, and securing such indebtedness by mortgage, deed of trust, pledge or other lien on MAALP's assets; and distribution of MAALP's cash or other assets in accordance with the Partnership Agreement. MAA can generally, at its sole discretion, issue and redeem OP Units and determine the consideration to be received or the redemption price to be paid, as applicable. The general partner may delegate these and other powers granted if the general partner remains in supervision of the designee.

Under the Partnership Agreement, MAALP may issue Class A OP Units and Class B OP Units. Class A OP Units are any OP Units other than Class B OP Units, while Class B OP Units are those issued to or held by MAALP's general partner or any of its subsidiaries. In general, the limited partners do not have the power to participate in the management or control of MAALP's business except in limited circumstances including changes in the general partner and protective rights if the general partner acts outside of the provisions provided in the Partnership Agreement. The transferability of Class A OP Units is also limited by the Partnership Agreement.

Net income (after allocations to preferred ownership interests) is allocated to the general partner and limited partners based on their respective ownership percentages of MAALP. Issuance or redemption of additional Class A OP Units or Class B OP Units changes the relative ownership percentage of the partners. The issuance of Class B OP Units generally occurs when MAA issues common stock and the proceeds from that issuance are contributed to MAALP in exchange for the issuance to MAA of a number of OP Units equal to the number of shares of common stock issued. Likewise, if MAA repurchases or redeems outstanding shares of common stock, MAALP generally redeems an equal number of Class B OP Units with similar terms held by MAA for a redemption price equal to the purchase price of those shares of common stock. At each reporting period, the allocation between general partner capital and limited partner capital is adjusted to account for the change in the respective percentage ownership of the underlying capital of MAALP. Holders of the Class A OP Units may require MAA to redeem their Class A OP Units, in which case MAA may, at its option, pay the redemption price either in cash (in an amount per Class A OP Unit equal, in general, to the average closing price of MAA's common stock on the NYSE over a specified period prior to the redemption date) or by delivering one share of MAA common stock (subject to adjustment under specified circumstances) for each Class A OP Unit so redeemed.

At March 31, 2019, a total of 4,105,171 Class A OP Units were outstanding and redeemable for 4,105,171 shares of MAA common stock, with an approximate value of $448.8 million, based on the closing price of MAA’s common stock on March 29, 2019 of $109.33 per share. At March 31, 2018, a total of 4,141,780 Class A OP Units were outstanding and redeemable for 4,141,780 shares of MAA common stock, with an approximate value of $377.9 million, based on the closing price of MAA’s common stock on March 29, 2018 of $91.24 per share. MAALP pays the same per unit distributions in respect to the OP Units as the per share dividends MAA pays in respect to its common stock.

As of March 31, 2019, MAALP had one outstanding series of cumulative redeemable preferred units, or the MAALP Series I Preferred Units. The MAALP Series I Preferred Units have the same characteristics as the MAA Series I preferred stock described in Note 8. As of March 31, 2019, 867,846 units of the MAALP Series I Preferred Units were outstanding.