Schedule II (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Beginning Balance		$ 1.5	$ 1.7	$ 1.5
Valuation Allowances and Reserves, Charged to Cost and Expense		3.0	2.2	3.4
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	[1]	1.9	2.4	3.2
Valuation Allowances and Reserves, Ending Balance		$ 2.6	$ 1.5	$ 1.7

[1] Uncollectible accounts receivable written off, net of recoveries.