Common Shares (Tables)

3 Months Ended

Jul. 31, 2011

Common Shares (Tables) [Abstract]

Common Shares Information

	July 31, 2011		April 30, 2011
Common shares authorized		150,000,000		150,000,000
Common shares outstanding		114,383,657		114,172,122
Treasury shares		14,221,508		14,432,043