Significant Transactions (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Property PartnershipUnit	Dec. 31, 2012 Property PartnershipUnit	Dec. 31, 2011 PartnershipUnit Property
Business Acquisition [Line Items]
Consolidated partnerships in which remaining limited partnership interests were acquired	3	11	12
Number of apartment communities owned by partnerships	5	17	15
Cost of limited partnership interests acquired	$ 17,900
Partners Capital Account Effect Of Changes In Ownership For Consolidated	17,170	50,654	22,305
Excess of consideration paid over the carrying amount of noncontrolling interests acquired		$ 44,777	$ 36,260