Commercial Group Land Sales (Details Textual) (USD $)	3 Months Ended	6 Months Ended
	Apr. 30, 2011	Jul. 31, 2011	Jan. 31, 2011
Commercial Group Land Sales (Additional Textuals)
Number of parcel of land and air rights sold			2
6 acre land parcel and air rights - Parcel 1 [Member]
Commercial Group Land Sales (Textuals)
Sales price of land parcel and air rights			$ 45,000,000
Cash deposit received			8,550,000
Amount of purchase price received	33,950,000
Gain on sale of parcel		42,622,000
10 acre land parcel and air rights - Parcel 2 [Member]
Commercial Group Land Sales (Textuals)
Sales price of land parcel and air rights			40,000,000
Cash deposit received			$ 2,500,000