Investments In Joint Ventures (Aggregate Balance Sheet And Statement Of Income Data For Unconsolidated Joint Ventures) (Details) (USD $)	1 Months Ended	3 Months Ended				9 Months Ended
	Nov. 04, 2011	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010		Dec. 31, 2010
Investments In Joint Ventures [Abstract]
Total assets		$ 1,322,500,000	[1]			$ 1,322,500,000	[1]			$ 935,300,000
Total third-party debt		1,066,900,000	[1]			1,066,900,000	[1]			810,100,000
Total equity		223,300,000	[1]			223,300,000	[1]			105,300,000
Total revenues		46,100,000		35,300,000		115,500,000		103,600,000
Net loss		(7,400,000)		(5,000,000)		(13,800,000)		(15,200,000)
Equity in loss		$ (556,000)	[2]	$ (244,000)	[2]	$ (166,000)	[2]	$ (785,000)	[2]
Number of unconsolidated joint venture ownership interests sold						3
Number of multifamily properties acquired by our discretionary funds	5					13

[1] During the nine months ended September 30, 2011, we sold our ownership interest in three unconsolidated joint ventures and our discretionary funds (the "Funds") acquired thirteen multifamily properties.

[2] Equity in income (loss) excludes our ownership interest of fee income from various property management services with our joint ventures.