Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Net operating loss carryforwards, deferred tax assets	$ 82.1	$ 70.5
Tax cuts and jobs act, income tax expense (benefit)		(16.4)
Unrecognized tax benefits, interest and penalties, income tax expense	1.4	0.5	$ 0.7
Unrecognized tax benefits, accrued interest and penalties	2.6	1.3
Unrecognized tax benefits	18.4
State [Member]
Income Taxes [Line Items]
Net operating loss carryforwards, deferred tax assets	15.7	11.5
Foreign [Member]
Income Taxes [Line Items]
Net operating loss carryforwards, deferred tax assets	66.0	57.4
Federal [Member]
Income Taxes [Line Items]
Net operating loss carryforwards, deferred tax assets	$ 0.1	$ 0.1