Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Excess tax benefit, amount	$ 8.4
Selling, General and Administrative Expenses
Property, Plant and Equipment [Line Items]
Shipping, handling and transportation costs	$ 68.6	$ 51.8	$ 45.8