Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Net impact of U.S. Tax Act	$ 4.2	$ 4.2	$ 0.0	$ 0.0
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense		10.0
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings, Provisional Income Tax Expense		$ 14.2
Deferred tax asset cumulative loss position term		3 years
Valuation allowances	11.6	$ 11.6	5.3
Unrecognized tax benefits, if recognized, would affect the effective tax rate	0.9	0.9	2.4
Net interest and penalties		(0.3)	(1.4)
Payment of interest and penalties accrued	0.2	0.2	0.4
Decrease in unrecognized tax benefits is reasonably possible	0.1	0.1
Undistributed earnings	136.0	136.0
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards for income tax purposes	32.4	32.4
Tax credit carryforward	3.1	3.1
Operating loss carryforward, subject to expiration	7.9	7.9
Valuation allowances	6.3	6.3	$ 4.5
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards for income tax purposes	2.1	2.1
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards for income tax purposes	$ 1.1	$ 1.1