Impairment of Real Estate, Impairment of Unconsolidated Entities and Write-Off of Abandoned Development Projects (Details 2) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jul. 31, 2013		Jul. 31, 2012
Fair Value, Measurements, Nonrecurring [Member]
Non-recurring Impairment of Real Estate Including Discontiued Operations
Fair value of impairment of real estate	$ 8,029		$ 80,929
Fair value valuation technique	Indicative Bids		Indicative Bids
Fair value unobservable input	Indicative Bids		Indicative Bids
Fair value range of input values impairment of real estate	N/A	[1]	N/A	[1]

[1] These fair value measurements were derived from bona fide purchase offers from third party prospective buyers, subject to the Company’s corroboration for reasonableness.