Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Intangible assets
Gross Carrying Amount, intangible assets subject to amortization	$ 445.9		$ 445.9		$ 403.1
Accumulated Amortization, intangible assets subject to amortization	(211.6)		(211.6)		(184.4)
Net Carrying Amount, intangible assets subject to amortization	234.3		234.3		218.7
Amortization expense related to intangible assets subject to amortization	9.2	$ 6.9	29.2	$ 21.5
Technology
Intangible assets
Gross Carrying Amount, intangible assets subject to amortization	294.4		294.4		272.6
Accumulated Amortization, intangible assets subject to amortization	(175.0)		(175.0)		(160.5)
Net Carrying Amount, intangible assets subject to amortization	119.4		119.4		112.1
Customer relationships
Intangible assets
Gross Carrying Amount, intangible assets subject to amortization	131.1		131.1		112.0
Accumulated Amortization, intangible assets subject to amortization	(27.1)		(27.1)		(18.1)
Net Carrying Amount, intangible assets subject to amortization	104.0		104.0		93.9
Non compete contracts
Intangible assets
Gross Carrying Amount, intangible assets subject to amortization	1.8		1.8		1.8
Accumulated Amortization, intangible assets subject to amortization	(1.8)		(1.8)		(1.8)
Trade names
Intangible assets
Gross Carrying Amount, intangible assets subject to amortization	13.2		13.2		11.6
Accumulated Amortization, intangible assets subject to amortization	(2.5)		(2.5)		(1.6)
Net Carrying Amount, intangible assets subject to amortization	10.7		10.7		10.0
Other
Intangible assets
Gross Carrying Amount, intangible assets subject to amortization	5.4		5.4		5.1
Accumulated Amortization, intangible assets subject to amortization	(5.2)		(5.2)		(2.4)
Net Carrying Amount, intangible assets subject to amortization	$ 0.2		$ 0.2		$ 2.7