Acquisitions Summary of Fair Value of Assets Acquired and Liabilities Assumed by Major Class (Details) (USD $) In Millions, unless otherwise specified	Apr. 30, 2014	Jan. 31, 2014	Feb. 06, 2014 Delcam	Feb. 06, 2014 Delcam Developed technologies	Feb. 06, 2014 Delcam Customer relationships and other non-current intangible assets	Feb. 06, 2014 Delcam Trade name	Apr. 30, 2014 Other	Apr. 30, 2014 Other Developed technologies	Apr. 30, 2014 Other Customer relationships and other non-current intangible assets	Apr. 30, 2014 Other Trade name
Business Acquisition [Line Items]
Finite-lived intangibles				$ 28.9	$ 39.7	$ 16.5		$ 9.8	$ 5.5	$ 1.9
Goodwill	1,263.0	1,009.9	196.2				50.3
Deferred revenue (current and non-current)			(10.4)				0
Deferred tax (liability)			(15.3)				(2.1)
Net tangible assets (liabilities)			29.0				(1.2)
Total			$ 284.6				$ 64.2