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]
Balance at Beginning of Year	$ 6.8	$ 5.2	$ 3.5
Charged to Expense / Against Revenue	(1.1)	3.7	3.7
Write-offs-Net of Recoveries	(2.3)	(2.1)	(2.0)
Balance at End of Year	$ 3.4	$ 6.8	$ 5.2