Quarterly Financial Information (Narrative) (Details) (USD $) In Millions, except Per Share data	3 Months Ended
	Oct. 31, 2010	Jul. 31, 2010	Apr. 30, 2010	Jan. 31, 2010	Oct. 31, 2009
Quarterly Financial Information
Restructuring charges after-tax, amount	$ 0.6	$ 0.1	$ 2.7	$ 3.6	$ 0.9
Restructuring charges after-tax, per share	$ 0.01		$ 0.03	$ 0.05	$ 0.01