Accounting Policies (Details Textual 3) (USD $)	9 Months Ended	12 Months Ended
	Oct. 31, 2013	Jan. 31, 2013
Accounting Policies (Textual) [Abstract]
Unrealized losses on an interest rate swap associated with office building	$ 105,890,000	$ 126,506,000
Notional amount	$ 640,000,000
Nonrecourse mortgage debt [Member]
Accounting Policies (Textual) [Abstract]
All-in lender interest rate	6.40%
Maturity date of swap agreement	Sep. 01, 2017