Cash, Cash Equivalents and Restricted Cash (Schedule of Cash, Cash Equivalents and Restricted Cash) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2018
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 152.8	$ 130.7
Restricted cash included in other current assets	0.2	0.2
Restricted cash included in other long-term assets	5.7	5.7
Total cash, cash equivalents and restricted cash	$ 158.7	$ 136.6	$ 159.7	$ 100.1