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Goodwill and Identifiable Assets (Goodwill) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Apr. 02, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Gross goodwill	$ 1,445.5		$ 1,421.1		$ 894.1
Goodwill, Acquired During Period	24.8	$ 528.2
Translation adjustment	(0.4)	(1.2)
Goodwill	1,445.5		1,421.1
Apex
Goodwill [Roll Forward]
Gross goodwill	662.1		662.1		662.1
Oxford
Goodwill [Roll Forward]
Gross goodwill	230.4		230.8		$ 232.0
Translation adjustment	(0.4)	(1.2)
ECS
Goodwill [Roll Forward]
Gross goodwill	553.0		$ 528.2
Goodwill				$ 528.2
DHA | DHA
Goodwill [Roll Forward]
Goodwill, Acquired During Period	$ 24.8
ECS | ECS
Goodwill [Roll Forward]
Goodwill, Acquired During Period		$ 528.2

X

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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-Publisher FASB
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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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