Commitments and Contingencies (Details) (USD $)	6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
300 properties designed and built in violation of accessibility requirements	300
Projects in various stages of development	12
Units in various stages of development	3,871
Consolidated Project Under Development Commitment Fund	$ 1,000,000,000
Various stages of development with estimated completion dates ranging through September 30, 2016	Sep. 30, 2016
Number Of Apartments Units Under Development Unconsolidated Projects	176
Estimated completion period of project	Dec. 31, 2014
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	265,400,000
Investment in Joint Venture	327,900,000
Noncontrolling Interests - Partially Owned Properties	125,843,000	126,583,000
Company's Portion [Member]
Land purchase price	76,100,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	102,500,000
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	117,400,000
Unconsolidated Development Projects Held for and or Under Development [Domain]
Number Of Unconsolidated Projects	1
Parc on Powell (formerly 1333 Powell) [Domain]
Guarantor Obligations, Maximum Exposure	$ 19,700,000