Fair Value Measurements - Unobservable Input Reconciliation (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration liability, beginning balance		$ 6.4	$ 5.4	$ 6.3	$ 5.1
Foreign currency translation		(0.1)	0.0	(0.2)	0.1
Total losses included in earnings	[1]	0.2	0.3	0.4	0.5
Contingent consideration liability, ending balance		$ 6.5	$ 5.7	$ 6.5	$ 5.7

[1] Changes in the fair value of contingent consideration liabilities are included as a component of Acquisition and integration-related expenses within the Condensed Consolidated Statements of Operations.