Commitments to Acquire/Dispose of Real Estate (Details) - Jul. 31, 2015 $ in Thousands	USD ($) property
Commitments to Acquire Real Estate
Properties Acquired-Total | property	0
Rental Units Acquired - Total	2
Purchase Price - Total	$ 27,832
Commitments to Dispose of Real Estate
Properties Disposed - Total | property	2
Rental Units Disposed-Total	522
Sales Price For Commitments To Dispose	$ 134,738
Rental Properties Disposed of [Member]
Commitments to Dispose of Real Estate
Properties Disposed - Total | property	2
Rental Units Disposed-Total	522
Sales Price For Commitments To Dispose	$ 104,838
Land [Member]
Commitments to Dispose of Real Estate
Sales Price For Commitments To Dispose	$ 29,900
Land Parcels Contracted To Be Disposed	3
Consolidated Rental Properties [Member]
Commitments to Acquire Real Estate
Purchase Price - Total	$ 6,000
Land [Member]
Commitments to Acquire Real Estate
Purchase Price - Total	$ 21,832
Land Parcels Contracted To Be Acquired	2