Commitments and Contingencies (Details Textual) (USD $)	12 Months Ended		12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013 The Nets [Member]	May 12, 2010 The Nets [Member]
Significant Acquisitions and Disposals [Line Items]
Purchase of business segment (The Nets)			Aug. 16, 2004
Percentage of ownership sold				80.00%
Commitments And Contingencies (Textual)
Letters of credit	$ 67,456,000	$ 69,389,000
Maximum potential payment	158,442,000
Outstanding balance of partners share of carve outs and environmental guarantees	861,333,000
Maximum net exposure	284,180,000
Maximum amount due, under completion guarantee	40,928,000
Insurance coverage of other indemnifying parties	$ 100,000,000