Summary of significant accounting policies (Narrative) (Details) (USD $)	9 Months Ended
	Oct. 31, 2012 Y
Summary Of Significant Accounting Policies 1	$ 500
Summary Of Significant Accounting Policies 2	3
Summary Of Significant Accounting Policies 3	7
Summary Of Significant Accounting Policies 4	20,000,000
Summary Of Significant Accounting Policies 5	67,261,764
Summary Of Significant Accounting Policies 6	178,156,230
Summary Of Significant Accounting Policies 7	187,086,566
Summary Of Significant Accounting Policies 8	197,741,128
Summary Of Significant Accounting Policies 9	168,133,617