Impairment of Real Estate, Impairment of Unconsolidated Entities and Write-Off of Abandoned Development Projects (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Schedule of Impairment of Real Estate [Line Items]
Impairment of Real Estate	$ 30,660	$ 235	$ 4,763
Halle Building (Office Building) [Member]
Schedule of Impairment of Real Estate [Line Items]
Impairment of Real Estate	30,200	0	0
Development Property Waterfront Station [Member]
Schedule of Impairment of Real Estate [Line Items]
Impairment of Real Estate	0	0	3,103
Other [Member]
Schedule of Impairment of Real Estate [Line Items]
Impairment of Real Estate	$ 460	$ 235	$ 1,660