Impairment of Real Estate, Impairment of Unconsolidated Entities and Write-Off of Abandoned Development Projects (Details) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 30, 2012
Fair Value, Measurements, Nonrecurring [Member]
Non-recurring Impairment of Real Estate Including Discontiued Operations
Fair value of impairment of real estate	$ 4,400
Fair value valuation technique	Indicative Bid
Fair value unobservable input	Indicative Bid
Fair value range of input values impairment of real estate	N/A	[1]

[1] This fair value measurement was developed by a third party source, subject to the Company's corroboration for reasonableness.