Supplementary Financial Statement Information (Details4) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill balance		$ 253.8
Adjustment to acquisition purchase price		1.2
Goodwill balance	$ 255.0	255.0
Intangible Assets, Gross Amount	56.9	56.9	$ 56.9
Intangible Assets, Accumulated Amortization	(8.7)	(8.7)	(4.0)
Intangible Assets, Net Amount	48.2	48.2	52.9
Amortization of Intangible Assets	2.3	4.7
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross Amount	36.6	36.6	36.6
Intangible Assets, Accumulated Amortization	(4.8)	(4.8)	(2.2)
Intangible Assets, Net Amount	31.8	31.8	34.4
Technology
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross Amount	19.3	19.3	19.3
Intangible Assets, Accumulated Amortization	(3.0)	(3.0)	(1.4)
Intangible Assets, Net Amount	16.3	16.3	17.9
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross Amount	1.0	1.0	1.0
Intangible Assets, Accumulated Amortization	(0.9)	(0.9)	(0.4)
Intangible Assets, Net Amount	$ 0.1	$ 0.1	$ 0.6