Income Taxes (Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Depreciation expense	$ (14.3)	$ (13.3)
Deferred Tax Assets Leasing liabilities	23.3	25.7
Deferred Tax Liability Leasing Asset	(22.1)	(24.8)
Allowance for doubtful accounts	1.4	1.8
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation	14.8	12.0
Stock-based compensation	8.4	9.2
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Other	22.5	0.0
Other	3.0	3.4
Net operating loss carryforwards - foreign	0.8	0.8
Valuation allowance	(0.5)	(0.8)
Deferred Tax Liabilities, net of deferred tax assets and valuation allowance	108.7	98.7
Total deferred income tax assets (liabilities)	(108.2)	(97.9)
Deferred Tax Liabilities, Goodwill and Intangible Assets	$ 146.0	$ 112.7