Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2012
Income Tax Examination [Line Items]
U.S. statutory income tax rate	21.00%	35.00%
Income tax benefit	$ (4.3)	$ (3.5)
Income before income tax	6.1	0.1
Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Amount	(5.6)	0.0
Income Tax Reconciliation Deductions Excess Tax Benefits	$ 2.5	5.3
State and Local Jurisdiction | Minimum
Income Tax Examination [Line Items]
Statutes of limitation, period	2 years
State and Local Jurisdiction | Maximum
Income Tax Examination [Line Items]
Statutes of limitation, period	5 years
Domestic Tax Authority | Internal Revenue Service (IRS)
Income Tax Examination [Line Items]
Tax Cuts and Jobs Act, Incomplete Accounting, Provisional Income Tax Expense (Benefit)			$ (25.7)
Tax Cuts and Jobs Act, Incomplete Accounting, Transition Toll Tax for Accumulated Foreign Earnings, Provisional Income Tax Expense, net of foreign tax credits			24.0
Deferred Tax Assets, Tax Credit Carryforwards, Foreign			14.0
Tax Cuts and Jobs Act, Incomplete Accounting, Change in Tax Rate, Deferred Tax Liability, Provisional Income Tax Benefit			$ 49.7
Domestic Tax Authority | Internal Revenue Service (IRS) | Earliest Tax Year
Income Tax Examination [Line Items]
Open tax year	2014
Foreign Tax Authority | Minimum
Income Tax Examination [Line Items]
Statutes of limitation, period	2 years
Foreign Tax Authority | Maximum
Income Tax Examination [Line Items]
Statutes of limitation, period	5 years
Foreign Tax Authority | Australian Taxation Office | Earliest Tax Year
Income Tax Examination [Line Items]
Open tax year	2013
Foreign Tax Authority | Secretariat of the Federal Revenue Bureau of Brazil
Income Tax Examination [Line Items]
Income Tax Examination, Interest Expense	$ 0.3	$ 0.7
Foreign Tax Authority | Secretariat of the Federal Revenue Bureau of Brazil | Earliest Tax Year
Income Tax Examination [Line Items]
Open tax year	2012
Foreign Tax Authority | Secretariat of the Federal Revenue Bureau of Brazil | Tax Year 2008 to 2010
Income Tax Examination [Line Items]
Unrecognized Tax Benefits	$ 24.6
Foreign Tax Authority | Secretariat of the Federal Revenue Bureau of Brazil | Tax Year 2007 to 2012
Income Tax Examination [Line Items]
Unrecognized Tax Benefits	$ 33.4			$ 44.5
Income Tax Contingency, Potential Assessment, Acquisition, Fair Value of Liabilities Accrued				$ 43.3
Foreign Tax Authority | Secretariat of the Federal Revenue Bureau of Brazil | Minimum
Income Tax Examination [Line Items]
Penalty rate	75.00%
Foreign Tax Authority | Secretariat of the Federal Revenue Bureau of Brazil | Maximum
Income Tax Examination [Line Items]
Penalty rate	150.00%
Foreign Tax Authority | Canada Revenue Agency | Earliest Tax Year
Income Tax Examination [Line Items]
Open tax year	2009
Foreign Tax Authority | Federal Ministry of Finance, Germany | Earliest Tax Year
Income Tax Examination [Line Items]
Open tax year	2011
Foreign Tax Authority | Swedish Tax Agency (Skatteverket) | Earliest Tax Year
Income Tax Examination [Line Items]
Open tax year	2011
Foreign Tax Authority | Her Majesty's Revenue and Customs (HMRC) | Earliest Tax Year
Income Tax Examination [Line Items]
Open tax year	2016