Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Intangible assets
Gross Carrying Amount, intangible assets subject to amortization	$ 239.4		$ 236.0
Accumulated Amortization, intangible assets subject to amortization	(163.3)		(154.2)
Net Carrying Amount, intangible assets subject to amortization	76.1		81.8
Gross Carrying Amount, total intangible assets	240.1		236.6
Net Carrying Amount, total intangible assets	76.8		82.4
Amortization expense related to intangible assets subject to amortization	6.8	$ 6.9
In-process research and development
Intangible assets
Gross Carrying Amount, intangible assets not subject to amortization	0.7		0.6
Net Carrying Amount, intangible assets not subject to amortization	0.7		0.6
Existing technology and related patents
Intangible assets
Gross Carrying Amount, intangible assets subject to amortization	198.6		195.4
Accumulated Amortization, intangible assets subject to amortization	(146.8)		(138.9)
Net Carrying Amount, intangible assets subject to amortization	51.8		56.5
Customer relationships
Intangible assets
Gross Carrying Amount, intangible assets subject to amortization	34.7		34.6
Accumulated Amortization, intangible assets subject to amortization	(13.9)		(12.9)
Net Carrying Amount, intangible assets subject to amortization	20.8		21.7
Non compete contracts
Intangible assets
Gross Carrying Amount, intangible assets subject to amortization	1.8		1.8
Accumulated Amortization, intangible assets subject to amortization	(1.6)		(1.5)
Net Carrying Amount, intangible assets subject to amortization	0.2		0.3
Trade names
Intangible assets
Gross Carrying Amount, intangible assets subject to amortization	4.3		4.2
Accumulated Amortization, intangible assets subject to amortization	(1.0)		(0.9)
Net Carrying Amount, intangible assets subject to amortization	$ 3.3		$ 3.3