Commitments to Acquire/Dispose of Real Estate (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012
Commitments to Acquire Real Estate
Properties Acquired-Total	0
Land Parcels Contracted to be Acquired	4
Rental Units Acquired - Total	0
Purchase Price - Total	$ 73,500
Commitments to Dispose of Real Estate
Properties Disposed - Total	3
Rental Units Disposed-Total	699
Sales price-Rental Properties	54,100
Land Parcel [Member]
Commitments to Acquire Real Estate
Land Parcels Contracted to be Acquired	0
Rental Units Acquired - Total	0
Purchase Price - Total	73,500
Rental Properties Disposed of [Member]
Commitments to Dispose of Real Estate
Properties Disposed - Total	3
Rental Units Disposed-Total	699
Sales price-Rental Properties	$ 54,100