Schedule II - Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	$ 6.4	$ 6.2	$ 6.3
Net bad debt expenses	0.8	0.0	1.4
Additions (deductions)	(0.5)	0.2	(1.5)
Ending Balance	$ 6.7	$ 6.4	$ 6.2