Consolidated Balance Sheets (Parenthetical) (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified							3 Months Ended	12 Months Ended
	Apr. 30, 2012 Variable interest entities	Jan. 31, 2012 Variable interest entities	Apr. 30, 2012 Common Stock Class A	Jan. 31, 2012 Common Stock Class A	Apr. 30, 2012 Common Stock Class B	Jan. 31, 2012 Common Stock Class B	Apr. 30, 2012 Series A Preferred Stock	Jan. 31, 2012 Series A Preferred Stock	Apr. 30, 2012 Other Preferred Stock	Jan. 31, 2012 Other Preferred Stock
Real Estate, net	$ 2,203,600	$ 2,103,800
Cash and equivalents	23,200	17,800
Restricted cash and escrowed funds	190,400	348,100
Other assets	132,000	130,800
Mortgage debt and notes payable, nonrecourse	1,144,900	1,122,000
Senior and Subordinated debt	29,000	29,000
Accounts payable, accrued expenses and other liabilities	$ 187,300	$ 171,000
Preferred Stock, without par value
Preferred stock, liquidation preference							$ 50	$ 50
Preferred stock, shares authorized							6,400,000	6,400,000	13,600,000	13,600,000
Preferred stock, shares issued							4,399,998	4,399,998
Preferred stock, shares outstanding							4,399,998	4,399,998
Preferred stock dividend rate							7.00%	7.00%
Price per share			$ 0.333	$ 0.333	$ 0.333	$ 0.333
Common stock, shares authorized			371,000,000	371,000,000	56,000,000	56,000,000
Common stock, shares issued			148,687,783	148,336,178	20,911,371	20,934,335
Common stock, shares outstanding			148,501,425	148,227,849	20,911,371	20,934,335
Common stock, shares issuable					26,257,961	26,257,961
Treasury stock, Class A Shares			186,358	108,329