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Consolidation and Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) (USD $)
In Thousands, except Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2013
Property
States
Mar. 31, 2012
Dec. 31, 2012
Real Estate Properties [Line Items]      
Number of units under development community 774    
Number of owned or owned interests of apartment communities 151    
Number of apartments included in a community 44,547    
Capital improvements in progress $ 51,016   $ 50,844
Number of Development Properties 3    
Number of states in which apartment units are located 12    
Operating partnership units outstanding 41,796,045 40,390,861  
General Partners' Capital Account, Units Outstanding 40,088,385 38,455,153 39,721,461
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest 95.90% 95.20%  
Limited Partners' Capital Account, Units Outstanding 1,707,660 1,935,708 1,731,672
Percentage of Consolidated Rental Revenue Generated by the Operating Partnership 90.00% 89.50%  
Development Properties [Member]
     
Real Estate Properties [Line Items]      
Number of owned or owned interests of apartment communities 2    
Number of apartments included in a community 106    
Mid America Multifamily Fund I, LLC
     
Real Estate Properties [Line Items]      
Number Of Properties Acquired 1    
Number Of Units Acquired In Real Estate Property 316    
Mid America Multifamily Fund II, LLC
     
Real Estate Properties [Line Items]      
Number Of Properties Acquired 4    
Number Of Units Acquired In Real Estate Property 1,156    
Under Development
     
Real Estate Properties [Line Items]      
Number of owned or owned interests of apartment communities 4    
Square Footage of Real Estate Property 107,000    
Expected Costs [Member]
     
Real Estate Properties [Line Items]      
Capital improvements in progress 101,300    
Costs Incurred to Date [Member]
     
Real Estate Properties [Line Items]      
Capital improvements in progress $ 56,300    
Minimum [Member]
     
Real Estate Properties [Line Items]      
Percentage Of Ownership Interests 70.00%    
Maximum [Member]
     
Real Estate Properties [Line Items]      
Percentage Of Ownership Interests 100.00%