Impairment of Real Estate, Impairment of Unconsolidated Entities and Write-Off of Abandoned Development Projects (Details) (USD $)	3 Months Ended		6 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of real estate	$ 8,055,000	$ 460,000	$ 8,055,000	$ 460,000
Investment in triple net lease retail property [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of real estate	6,870,000	0	6,870,000	0
Other [Member]
Schedule of Impairment of Real Estate Included in Continuing Operations [Line Items]
Impairment of real estate	$ 1,185,000	$ 460,000	$ 1,185,000	$ 460,000