Impairment of Real Estate, Impairment of Unconsolidated Entities, Write-Off of Abandoned Development Projects and Gain on Extinguishment of Debt (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2011	Oct. 31, 2010
Summary of Company's impairment of unconsolidated entities
Impairment of unconsolidated entities	$ 41,289	$ 21,564	$ 41,289	$ 36,745
Commercial land and development rights [Member]
Summary of Company's impairment of unconsolidated entities
Impairment of unconsolidated entities	4,610		4,610
Mixed-Use Land Development [Member] | Sterling Lakes [Member]
Summary of Company's impairment of unconsolidated entities
Impairment of unconsolidated entities	1,700		1,700
Mixed-Use Land Development [Member] | Four Museum Park properties [Member]
Summary of Company's impairment of unconsolidated entities
Impairment of unconsolidated entities		18,311		18,311
Mixed-Use Land Development [Member] | Mercy Campus [Member]
Summary of Company's impairment of unconsolidated entities
Impairment of unconsolidated entities				1,817
Mixed-Use Land Development [Member] | Old Stone Crossing at Caldwell Creek [Member]
Summary of Company's impairment of unconsolidated entities
Impairment of unconsolidated entities				743
Office Buildings [Member] | Mesa del Sol Aperture Center [Member]
Summary of Company's impairment of unconsolidated entities
Impairment of unconsolidated entities		2,733		2,733
Office Buildings [Member] | 818 Mission Street [Member]
Summary of Company's impairment of unconsolidated entities
Impairment of unconsolidated entities				4,018
Office Buildings [Member] | Bulletin Building [Member]
Summary of Company's impairment of unconsolidated entities
Impairment of unconsolidated entities				3,543
Specialty Retail Centers [Member] | Village at Gulfstream Park [Member]
Summary of Company's impairment of unconsolidated entities
Impairment of unconsolidated entities	34,579		34,579
Specialty Retail Centers [Member] | Metreon [Member]
Summary of Company's impairment of unconsolidated entities
Impairment of unconsolidated entities				4,595
Other [Member]
Summary of Company's impairment of unconsolidated entities
Impairment of unconsolidated entities	$ 400	$ 520	$ 400	$ 985