Summary of Significant Accounting Policies (Income Tax, Shipping and Handling Costs and Advertising Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Deferred tax liabilities	$ 100.7	$ 106.3
Net current deferred tax asset	128.4	199.3
Total deferred tax liabilities	229.1	305.6
Deferred tax assets, valuation allowance	157.4	177.1
Shipping and handling costs	112.5	114.2	$ 118.0
Advertising expense	$ 6.4	$ 7.9	$ 10.4