Commercial Group Land Sales (Details Textual) (USD $)		3 Months Ended		12 Months Ended		3 Months Ended	12 Months Ended
	Jan. 31, 2011 parcel	Oct. 31, 2011 Parcel 1 [Member]	Apr. 30, 2011 Parcel 1 [Member]	Jan. 31, 2012 Parcel 1 [Member]	Jan. 31, 2011 Parcel 1 [Member] acre	Apr. 30, 2012 Parcel 2 [Member]	Jan. 31, 2013 Parcel 2 [Member]	Jan. 31, 2012 Parcel 2 [Member]	Jan. 31, 2011 Parcel 2 [Member] acre
Commercial Group Land Sales (Textual) [Abstract]
Number of parcels of land and air rights sold	2
Area of land parcel sold (in acres)					6				10
Sales price of land parcel and air rights					$ 45,000,000				$ 40,000,000
Cash deposit received					8,550,000			7,000,000
Amount of purchase price received		2,500,000	33,950,000			33,000,000
Gain on sale of land parcel and air rights				$ 42,622,000			$ 36,484,000