Commitments and Contingencies (Details) (USD $)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
300 properties designed and built in violation of accessibility requirements	300
Projects in various stages of development	13
Units in various stages of development	3,327
Consolidated Project Under Development Commitment Fund	$ 608,741,000
Various stages of development with estimated completion dates ranging through June 30, 2016	Jun. 30, 2016
Number Of Unconsolidated Projects	3
Number Of Apartments Units Under Development Unconsolidated Projects	1,012
Estimated completion period of project	Sep. 30, 2014
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	108,000,000
Investment in Joint Venture	259,138,385
Noncontrolling Interests - Partially Owned Properties	110,635,000	77,688,000
Joint Venture Partner [Member]
Land purchase price	57,900,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	75,700,000
Noncontrolling Interests - Partially Owned Properties	95,528,824
Company's Portion [Member]
Land purchase price	76,100,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	102,500,000
Enclave at Wellington [Domain]
Business Acquisition, Percentage of Voting Interests Acquired	95.00%
Parkside at Emeryville [Domain]
Guarantor Obligations, Maximum Exposure	$ 19,700,000