Income Taxes (Tax Credits Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Tax Credit Carryforward [Line Items]
Deferred tax credits	$ 11.5	$ 10.2
U.S. Federal
Tax Credit Carryforward [Line Items]
Deferred tax credits	3.8	2.6
U.S. Federal | Alternative Minimum Tax Credit Carryforward
Tax Credit Carryforward [Line Items]
Deferred tax credits	1.2
U.S. Federal | Research Tax Credit Carryforward
Tax Credit Carryforward [Line Items]
Deferred tax credits	2.6
Foreign
Tax Credit Carryforward [Line Items]
Deferred tax credits	7.7	$ 7.6
Foreign | Withholding tax on inter-company debt
Tax Credit Carryforward [Line Items]
Deferred tax credits	$ 7.7