Impairment of Real Estate, Impairment of Unconsolidated Entities and Write-Off of Abandoned Development Projects(Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Schedule of Equity Method Investments [Line Items]
Impairment of Unconsolidated Entities	$ 390	$ 40,284	$ 72,459
Village at Gulfstream Park (Specialty Retail Center) [Member]
Schedule of Equity Method Investments [Line Items]
Impairment of Unconsolidated Entities	0	35,674	35,000
Metreon (Specialty Retail Center) [Member]
Schedule of Equity Method Investments [Line Items]
Impairment of Unconsolidated Entities	0	0	4,595
Commercial land and development rights [Member]
Schedule of Equity Method Investments [Line Items]
Impairment of Unconsolidated Entities	0	4,610	0
Four Museum Park properties at Central Station [Member]
Schedule of Equity Method Investments [Line Items]
Impairment of Unconsolidated Entities	0	0	18,311
818 Mission Street (Office Building) [Member]
Schedule of Equity Method Investments [Line Items]
Impairment of Unconsolidated Entities	0	0	4,018
Bulletin Building (Office Building) [Member]
Schedule of Equity Method Investments [Line Items]
Impairment of Unconsolidated Entities	0	0	3,543
Other [Member]
Schedule of Equity Method Investments [Line Items]
Impairment of Unconsolidated Entities	$ 390	$ 0	$ 6,992