Acquisitions Summary of Fair Value of Assets Acquired and Liabilities Assumed by Major Class (Details) (USD $) In Millions, unless otherwise specified	Jul. 31, 2014	Jan. 31, 2014	Jun. 27, 2014 Shotgun	Jun. 27, 2014 Shotgun Developed technologies	Jun. 27, 2014 Shotgun Customer relationships and other non-current intangible assets	Jun. 27, 2014 Shotgun Trade name	May 29, 2014 Within	May 29, 2014 Within Developed technologies	May 29, 2014 Within Customer relationships and other non-current intangible assets	May 29, 2014 Within Trade name	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	Jul. 31, 2014 Other	Jul. 31, 2014 Other Developed technologies	Jul. 31, 2014 Other Customer relationships and other non-current intangible assets	Jul. 31, 2014 Other Trade name
Business Acquisition [Line Items]
Finite-lived intangibles				$ 5.4	$ 7.5	$ 1.6		$ 4.6	$ 3.6	$ 1.2		$ 28.9	$ 39.7	$ 16.5		$ 25.4	$ 7.3	$ 4.5
Goodwill	1,447.6	1,009.9	43.2				80.6				192.8				117.5
Deferred revenue (current and non-current)			(0.7)				0				(10.4)				(0.2)
Deferred tax (liability)			(2.6)				(1.7)				(15.3)				(2.1)
Net tangible assets (liabilities)			0.1				(0.3)				32.4				(0.9)
Total			$ 54.5				$ 88.0				$ 284.6				$ 151.5