Fair Value Measurements - Unobservable Input Reconciliation (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration liability, beginning balance		$ 5.7	$ 5.0	$ 5.1	$ 0.0
Issuance of contingent consideration in connection with acquisitions		0.0	0.0	0.0	4.9
Settlements of contingent consideration liabilities		0.0	0.0	0.0	0.0
Foreign currency translation		0.4	(0.1)	0.5	0.0
Total losses included in earnings	[1]	0.1	0.2	0.6	0.2
Contingent consideration liability, ending balance		$ 6.2	$ 5.1	$ 6.2	$ 5.1

[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.