Income Taxes - Balance Sheet Location for Deferred Items and Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Undistributed foreign earnings	$ 7.9	$ 1.7
Deferred tax assets and liabilities
Other long-term assets	1.4	1.1
Other long-term liabilities	(200.5)	(115.0)
Net deferred tax liabilities	(199.1)	(113.9)
Cumulative unremitted earnings and cumulative translation adjustments	608.0
Reconciliation of the beginning and ending amount of unrecognized tax benefits
Balance at the beginning of the period	24.6	27.7	$ 23.8
Additions based on tax positions related to current year	3.0	0.6	0.9
Additions related to purchase accounting	15.8	0.0	3.0
Adjustments for tax positions of prior years	1.5	0.0	1.3
Reductions due to statute of limitations	(3.3)	(2.1)	(1.2)
Reductions due to settlements	(1.7)	(1.4)	0.0
Adjustments due to foreign exchange rates		(0.2)	(0.1)
Adjustments due to foreign exchange rates	0.7
Balance at the end of the period	40.6	24.6	27.7
Uncertain tax position that would impact effective tax rate	44.3
Total amount of interest and penalties accrued	$ 6.5	$ 4.7	$ 4.9
Number of months within which state and foreign audits may conclude	12 months
Minimum
Income Tax Contingency [Line Items]
Decrease in unrecognized tax benefits is reasonably possible	$ 6.0
Maximum
Income Tax Contingency [Line Items]
Decrease in unrecognized tax benefits is reasonably possible	$ 7.0