Investments in Unconsolidated Entities (Details 2) (USD $)	3 Months Ended		9 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2011	Oct. 31, 2010
Summary of Impairment of investments in unconsolidated entities
Impairment of real estate	$ 10,707,000	$ 5,703,000	$ 15,777,000	$ 6,803,000
Total Impairment of investment in unconsolidated entities	41,289,000	21,564,000	41,289,000	36,002,000
Impairment of unconsolidated entities	41,289,000	21,564,000	41,289,000	36,745,000
Commercial land and development rights [Member]
Summary of Impairment of investments in unconsolidated entities
Total Impairment of investment in unconsolidated entities	4,610,000		4,610,000
Impairment of unconsolidated entities	4,610,000		4,610,000
Mixed-Use Land Development [Member]
Summary of Impairment of investments in unconsolidated entities
Company's portion of impairment of real estate				743,000
Mixed-Use Land Development [Member] | Mercy Campus [Member]
Summary of Impairment of investments in unconsolidated entities
Total Impairment of investment in unconsolidated entities				1,817,000
Impairment of unconsolidated entities				1,817,000
Mixed-Use Land Development [Member] | Old Stone Crossing at Caldwell Creek [Member]
Summary of Impairment of investments in unconsolidated entities
Impairment of real estate				1,457,000
Impairment of unconsolidated entities				743,000
Mixed-Use Land Development [Member] | Sterling Lakes [Member]
Summary of Impairment of investments in unconsolidated entities
Total Impairment of investment in unconsolidated entities	1,700,000		1,700,000
Impairment of unconsolidated entities	1,700,000		1,700,000
Mixed-Use Land Development [Member] | Four Museum Park properties [Member]
Summary of Impairment of investments in unconsolidated entities
Total Impairment of investment in unconsolidated entities		18,311,000		18,311,000
Impairment of unconsolidated entities		18,311,000		18,311,000
Office Buildings [Member] | Mesa del Sol Aperture Center [Member]
Summary of Impairment of investments in unconsolidated entities
Total Impairment of investment in unconsolidated entities		2,733,000		2,733,000
Impairment of unconsolidated entities		2,733,000		2,733,000
Office Buildings [Member] | 818 Mission Street [Member]
Summary of Impairment of investments in unconsolidated entities
Total Impairment of investment in unconsolidated entities				4,018,000
Impairment of unconsolidated entities				4,018,000
Office Buildings [Member] | Bulletin Building [Member]
Summary of Impairment of investments in unconsolidated entities
Total Impairment of investment in unconsolidated entities				3,543,000
Impairment of unconsolidated entities				3,543,000
Specialty Retail Centers [Member] | Village at Gulfstream Park [Member]
Summary of Impairment of investments in unconsolidated entities
Total Impairment of investment in unconsolidated entities	34,579,000		34,579,000
Impairment of unconsolidated entities	34,579,000		34,579,000
Specialty Retail Centers [Member] | Metreon [Member]
Summary of Impairment of investments in unconsolidated entities
Total Impairment of investment in unconsolidated entities				4,595,000
Impairment of unconsolidated entities				4,595,000
Other [Member]
Summary of Impairment of investments in unconsolidated entities
Impairment of real estate	450,000	450,000	685,000	450,000
Total Impairment of investment in unconsolidated entities	400,000	520,000	400,000	985,000
Impairment of unconsolidated entities	$ 400,000	$ 520,000	$ 400,000	$ 985,000