Subsequent Event (Details)	103 Months Ended
	Jul. 31, 2011	Sep. 22, 2011
Subsequent Events [Abstract]
Share increase in the Company's stock repurchase program (in shares)		20,000,000
Total current authorization of stock repurchase program (in shares)		49,000,000
Shares repurchased under the scheme (in shares)	20,453,037
Shares available for repurchase under the program (in shares)		28,546,963
Subsequent Event, Date	Sep. 22, 2011