Discontinued Operations and Gain (Loss) on Disposition of Rental Properties (Details)	3 Months Ended		6 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2011	Jul. 31, 2010
Waterfront Station - East 4th & West 4th Buildings [Member]
Summary of rental properties included in discontinued operations
Location			Washington, D.C.
Square Feet / Number of units/Rooms			631000 square feet
Period Disposed			Q2-2011
Period Status	Yes	Yes	Yes	Yes
Charleston Marriott hotel [Member]
Summary of rental properties included in discontinued operations
Location			Charleston, West Virginia
Square Feet / Number of units/Rooms			352 rooms
Period Disposed			Q1-2011
Period Status		Yes	Yes	Yes
Simi Valley Town Center [Member]
Summary of rental properties included in discontinued operations
Location			Simi Vally, California
Square Feet / Number of units/Rooms			612,000 square feet
Period Disposed			Q4-2010
Period Status		Yes		Yes
Investment In Triple Net Lease Property [Member]
Summary of rental properties included in discontinued operations
Location			Pueblo, Coloado
Square Feet / Number of units/Rooms			203,000 square feet
Period Disposed			Q4-2010
Period Status		Yes		Yes
Saddle Rock Village [Member]
Summary of rental properties included in discontinued operations
Location			Aurora, Colorado
Square Feet / Number of units/Rooms			294,000 square feet
Period Disposed			Q3-2010
Period Status		Yes		Yes
101 San Fernando [Member]
Summary of rental properties included in discontinued operations
Location			San Jose, California
Square Feet / Number of units/Rooms			323 units
Period Disposed			Q2-2010
Period Status		Yes		Yes