Income Taxes (Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Income tax at U.S. statutory rate of 35%	$ 55.3	$ 43.8	$ 46.0
Effect of the U.S. Tax Act	(25.7)	0.0	0.0
State, local and other tax, net of federal benefit	3.6	2.4	2.1
U.S. effect of foreign dividends and withholding taxes	4.9	4.6	3.9
Unrealized foreign currency expense (benefit) on intercompany debt	0.0	0.7	(0.7)
Realized foreign exchange net loss on intercompany loans	0.0	(9.6)	0.0
Revaluation of previously held equity interest	0.0	(12.0)	0.0
Foreign income taxed at a lower effective rate	(6.9)	(4.6)	(5.6)
Interest on Brazilian Tax Assessment	2.2	2.8	2.7
Expiration of tax credits	0.0	10.9	1.0
Decrease in valuation allowance	(0.6)	(9.9)	(1.3)
Excess benefit from stock-based compensation	(5.6)	0.0	0.0
Other	(0.8)	0.5	(2.6)
Income tax expense	$ 26.4	$ 29.6	$ 45.5
Effective income tax rate	16.70%	23.70%	34.60%