Acquisitions Acquisition (Details) (USD $)	0 Months Ended			6 Months Ended
	Jun. 27, 2014 Shotgun	May 29, 2014 Within	Feb. 06, 2014 Delcam	Jul. 31, 2014 Other business_combination
Business Acquisition [Line Items]
Consideration	$ 54,500,000	$ 88,000,000	$ 284,600,000	$ 151,500,000
Cash consideration	51,200,000
Fair value of original convertible debt investment	3,300,000
Goodwill, expected tax deductible amount	$ 0	$ 78,900,000	$ 165,100,000
Number of businesses acquired				12