Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other Income Tax Expense [Line Items]
Effective income tax rate	14.30%	11.10%	17.60%	13.80%
Release of valuation allowances			$ 10.8
Excess tax benefits	$ 2.2		6.9
Foreign rate changes
Other Income Tax Expense [Line Items]
Other tax expense			14.8
Out-of-period adjustments
Other Income Tax Expense [Line Items]
Other tax expense			$ 5.1