Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	$ 3.7	$ 4.4	$ 4.4
Additions Charged to Costs and Expenses	0.2	0.1	(0.1)
Deductions	1.0	0.9	0.0
Other	1.1	0.1	0.1
Balance at End of Period	4.0	3.7	4.4
Allowance for deferred taxes
Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	6.4	6.8	9.8
Additions Charged to Costs and Expenses	1.9	0.0	2.3
Deductions	0.0	0.4	5.3
Other	0.0	0.0	0.0
Balance at End of Period	$ 8.3	$ 6.4	$ 6.8