Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Provisional tax benefit from remeasurement of deferred tax liabilities	$ 16.2
Transition tax for foreign earnings	$ 3.7
Statutory tax rate, percentage	35.00%	35.00%	35.00%
Deferred tax assets, net of operating losses	$ 22.5
Deferred tax assets, net of operating losses	3.5
Undistributed earnings of foreign subsidiaries	27.2
Cash held in foreign operations	24.4
Unrecognized tax benefits that would affect the effective tax rate	$ 0.3	$ 0.6
Minimum
Operating Loss Carryforwards [Line Items]
Statute of limitations expiration period, in years	4 years
Maximum
Operating Loss Carryforwards [Line Items]
Statute of limitations expiration period, in years	10 years
RBI
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits that would affect the effective tax rate	$ 3.2	$ 2.8