Shareholder's Equity (Details) (USD $)	12 Months Ended				12 Months Ended						3 Months Ended			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2013	Mar. 02, 2012	Dec. 31, 2013 At The Market (ATM) Programs	Dec. 31, 2012 At The Market (ATM) Programs	Dec. 31, 2011 At The Market (ATM) Programs	Dec. 31, 2013 At The Market ATM Programs	Dec. 31, 2012 At The Market ATM Programs	Dec. 31, 2011 At The Market ATM Programs	Mar. 31, 2012 Initial Public Offering	Aug. 26, 2010 Maximum	Dec. 31, 1999 Maximum	Dec. 31, 2013 Period Covered from 1999 to 2011	Dec. 31, 2013 Dividend And Distribution Reinvestment And Share Purchase Plan	Dec. 31, 2012 Dividend And Distribution Reinvestment And Share Purchase Plan	Dec. 31, 2011 Dividend And Distribution Reinvestment And Share Purchase Plan	Dec. 31, 2013 Dividend And Distribution Reinvestment And Share Purchase Plan Minimum	Dec. 31, 2013 Dividend And Distribution Reinvestment And Share Purchase Plan Maximum	Dec. 31, 2013 Noncontrolling Interest	Dec. 31, 2012 Noncontrolling Interest	Dec. 31, 2011 Noncontrolling Interest	Dec. 31, 2013 MAA	Dec. 31, 2012 MAA	Dec. 31, 2011 MAA
Stockholders Equity Note [Line Items]
Common stock, shares outstanding	74,830,726	42,316,398
Common Shares Issuable Upon Conversion Of Convertible Stock																				4,227,384	1,731,672
Common shares and operating partnership units outstanding	79,058,110	44,048,070
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	356,143	0
Stock Issued During Period, Shares, Acquisitions	31,916,765																			2,574,631
Treasury Stock, Shares, Acquired	5,029	15,565
Limited Partners' Capital Account	$ 256,771,304	$ 112,125,762
Redeemable Capital Shares Par Or Stated Value Per Share		$ 64.75																		$ 60.74
Percentage of Operating Partnership net income (percent)																				4.60%	4.50%	5.30%	95.40%	95.50%	94.70%
Optional cash investments in common shares																		250	5,000
Common stock registered for Dividend and Distribution Reinvestment and Share Purchase Plan (shares)																			7,600,000
Discount rate on sale of common stock (percent)																			5.00%
Common stock issued for shareholders to reinvest distributions (shares)															10,924	14,260	509,116
Discount rate for optional cash purchases (percent)															2.00%	2.00%	2.00%
Shares Subject To Issuance Pursuant To Sales Agreement			4,500,000									6,000,000
Common stock shares issued (shares)					365,011	1,155,511	3,303,273	4,134,989
Shares sold on underwritten public offering				1,955,000
Proceeds from issuance of common stock, net of applicable fees								24,800,000	75,900,000	204,500,000	120,000,000
Proceeds from issuance of common stock								25,100,000	77,000,000	207,700,000	124,100,000
Common stock authorized for repurchase plan (shares)													4,000,000.0
Common stock repurchased and retired (shares)														1,900,000
Common stock repurchased and retired, value														$ 42,000,000
Common stock repurchased and retired (dollars per share)														$ 22.54