Investments in Real Estate Entities (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Investment in Real Estate Entities
Gain on sale of communities	$ 11,216,000	$ 3,825,000	$ 65,267,000	$ 12,735,000
Fund I | Community located in Norwalk, CA
Investment in Real Estate Entities
Number of homes sold	192
Proceeds from sale of real estate	45,844,000
Gain on sale of communities	$ 1,472,000
Unconsolidated real estate entities
Investment in Real Estate Entities
Number of unconsolidated real estate entities	7		7
Unconsolidated real estate entities | Minimum
Investment in Real Estate Entities
Ownership interest percentage	15.20%		15.20%
Unconsolidated real estate entities | Maximum
Investment in Real Estate Entities
Ownership interest percentage	31.30%		31.30%