Acquisitions Summary of Fair Value of Assets Acquired and Liabilities Assumed by Major Class (Details) (USD $) In Millions, unless otherwise specified	Apr. 30, 2013
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net	$ 35.0
Other Acquistions [Member]
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Goodwill Amount	27.3
Business Acquisition, Purchase Price Allocation, Deferred Taxes Asset (Liability), Net, Noncurrent	0.7
Business Acquisition, Purchase Price Allocation, Net Tangible Assets	0.2
Other Acquistions [Member] | Developed Technology Rights [Member]
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets	4.3
Other Acquistions [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets	2.0
Other Acquistions [Member] | Trade Names [Member]
Business Acquisition [Line Items]
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets	$ 0.5