Organization, Basis of Presentation and Significant Accounting Policies (Details)	Mar. 31, 2013 state home community
Organization and Basis of Presentation
Number of operating apartment communities owned	245
Number of apartment homes included in operating apartment communities owned	73,477
Number of states where operating apartment communities owned are located	12
Number of communities with apartments under reconstruction	5
Number of apartment homes under reconstruction	2,164
Number of owned communities under construction	27
Expected number of apartment homes under construction	7,802
Communities under development rights	42
Estimated number of apartment homes in communities to be developed	12,040