Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets		$ 2.6
Impairment of Intangible Assets, Finite-lived		0.0	$ 0.0
IT Services and Hardware [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	[1]	140.8		$ 141.8
Finite-Lived Intangible Assets, Accumulated Amortization		12.1		9.5
Customer Relationships [Member] | IT Services and Hardware [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	[1]	115.4		116.0
Finite-Lived Intangible Assets, Accumulated Amortization		10.8		8.9
Trade Names [Member] | IT Services and Hardware [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	[1]	15.5		15.9
Finite-Lived Intangible Assets, Accumulated Amortization		0.8		0.4
Technology-Based Intangible Assets [Member] | IT Services and Hardware [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	[1]	9.9		9.9
Finite-Lived Intangible Assets, Accumulated Amortization		$ 0.5		$ 0.2

[1] Change in gross carrying amounts is due to foreign currency translation.