Financing Agreements (Schedule of Covenants) (Details) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	May 04, 2018 USD ($)	Dec. 31, 2017	Jun. 30, 2017 USD ($)	Dec. 31, 2016
Maximum [Member]
Debt Instrument [Line Items]
Secured Net Leverage Ratio						4.50
Maximum [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Secured Net Leverage Ratio	3.00	3.50		4.00
Accounts Receivable from Securitization			$ 0.0
Minimum [Member]
Debt Instrument [Line Items]
Interest Coverage Ratio						3.25
Minimum [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Interest Coverage Ratio	4.00	3.75		3.50
Securitization Program [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 110.0