Investments in Unconsolidated Entities (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Oct. 31, 2010	Oct. 31, 2011	Oct. 31, 2010
Gain (loss) on disposition of rental properties:
Gain on disposition of rental properties	$ 10,998		$ 10,998
Company's portion of gain on disposition of rental properties	8,658		8,658
Gain (loss) on disposition of equity method investments:
Gain (loss) on disposition of equity method investments		12,567	(830)
Metreon [Member] | Specialty Retail Centers [Member]
Gain (loss) on disposition of equity method investments:
Gain (loss) on disposition of equity method investments			(1,046)
Coachella Plaza [Member] | Specialty Retail Centers [Member]
Gain (loss) on disposition of equity method investments:
Gain (loss) on disposition of equity method investments			104
Southgate Mall [Member] | Specialty Retail Centers [Member]
Gain (loss) on disposition of equity method investments:
Gain (loss) on disposition of equity method investments			64
El Centro Mall [Member] | Specialty Retail Centers [Member]
Gain (loss) on disposition of equity method investments:
Gain (loss) on disposition of equity method investments			48
Metropolitan Lofts [Member] | Apartment Communities [Member]
Gain (loss) on disposition of equity method investments:
Gain (loss) on disposition of equity method investments		9,964
Twin Lake Towers [Member] | Apartment Communities [Member]
Gain (loss) on disposition of equity method investments:
Gain (loss) on disposition of equity method investments		2,603
Pebble Creek [Member] | Apartment Communities [Member]
Gain (loss) on disposition of rental properties:
Gain (loss) on disposition of rental properties	4,555		4,555
Woodbridge Crossing [Member] | Specialty Retail Centers [Member]
Gain (loss) on disposition of rental properties:
Gain (loss) on disposition of rental properties	$ 6,443		$ 6,443