Impairment of Real Estate, Impairment of Unconsolidated Entities, Write-Off of Abandoned Development Projects and Gain on Extinguishment of Debt (Details) (USD $)	3 Months Ended		9 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2011	Oct. 31, 2010
Schedule of Impairment of Real Estate [Line Items]
Impairment of real estate	$ 10,707,000	$ 5,703,000	$ 15,777,000	$ 6,803,000
250 Huron (Office Building) [Member]
Schedule of Impairment of Real Estate [Line Items]
Impairment of real estate	10,257,000	2,040,000	10,257,000	2,040,000
Portage Michigan Retail Property [Member]
Schedule of Impairment of Real Estate [Line Items]
Impairment of real estate			3,435,000
Land Projects Mill Creek [Member]
Schedule of Impairment of Real Estate [Line Items]
Impairment of real estate		110,000	1,400,000	560,000
Land Projects Gladden Farms [Member]
Schedule of Impairment of Real Estate [Line Items]
Impairment of real estate				650,000
Development property at Waterfront Station [Member]
Schedule of Impairment of Real Estate [Line Items]
Impairment of real estate		3,103,000		3,103,000
Other [Member]
Schedule of Impairment of Real Estate [Line Items]
Impairment of real estate	$ 450,000	$ 450,000	$ 685,000	$ 450,000