Restructuring (Details Textual) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2012 Position Facility	Oct. 31, 2011	Apr. 30, 2012
Restructuring (Textual) [Abstract]
Percent of positions reduced due to restructuring	75.00%		75.00%
Total expected restructuring charge	$ 245,000,000		$ 245,000,000
Restructuring costs incurred announcement-to-date			213,600,000
Reduction in positions due to restructuring			850
Cost of products sold restructuring	2,000,000	11,800,000	5,600,000	21,500,000
Total restructuring charges	$ 10,300,000	$ 22,200,000	$ 24,757,000	$ 41,700,000	$ 81,141,000
Plants announced to be closed			6