Discontinued Operations and Gain on Disposition of Rental Properties (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2012	Jul. 31, 2011
Gain Loss on Equity Method Investments [Line Items]
Equity Method Investment, Realized Gain (Loss) on Disposal	$ 16,107	$ 0	$ 16,107	$ 12,567
Village of Gulfstream Park (Specialty Retail Center) [Member]
Gain Loss on Equity Method Investments [Line Items]
Equity Method Investment, Realized Gain (Loss) on Disposal	14,479	0	14,479	0
Chagrin Plaza I & II (Office Buildings) [Member]
Gain Loss on Equity Method Investments [Line Items]
Equity Method Investment, Realized Gain (Loss) on Disposal	1,628	0	1,628	0
Metropolitan Lofts [Member]
Gain Loss on Equity Method Investments [Line Items]
Equity Method Investment, Realized Gain (Loss) on Disposal	0	0	0	9,964
Twin Lake Towers [Member]
Gain Loss on Equity Method Investments [Line Items]
Equity Method Investment, Realized Gain (Loss) on Disposal	$ 0	$ 0	$ 0	$ 2,603