Discontinued Operations and Gain on Disposition of Rental Properties (Details 3) (USD $)	3 Months Ended		6 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012
Gain (Loss) on Disposition of Rental Properties [Line Items]
Pre-tax gain on disposition of rental properties	$ 21,221,000	$ 0	$ 43,103,000	$ 8,879,000
Sheraton Station Square (Hotel) [Member]
Gain (Loss) on Disposition of Rental Properties [Line Items]
Pre-tax gain on disposition of rental properties	18,096,000	0	18,096,000	0
Higbee Building (Office Building) [Member]
Gain (Loss) on Disposition of Rental Properties [Line Items]
Pre-tax gain on disposition of rental properties	2,922,000	0	2,922,000	0
Millender Center (Apartment Community) [Member]
Gain (Loss) on Disposition of Rental Properties [Line Items]
Pre-tax gain on disposition of rental properties	0	0	21,660,000	0
Triple net lease property [Member]
Gain (Loss) on Disposition of Rental Properties [Line Items]
Pre-tax gain on disposition of rental properties	0	0	222,000	0
Quebec Square (Speciality Retail Center) [Member]
Gain (Loss) on Disposition of Rental Properties [Line Items]
Pre-tax gain on disposition of rental properties	0	0	0	8,879,000
Other [Member]
Gain (Loss) on Disposition of Rental Properties [Line Items]
Pre-tax gain on disposition of rental properties	$ 203,000	$ 0	$ 203,000	$ 0