Schedule II (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Beginning Balance		$ 1.5	$ 1.5	$ 1.4
Valuation Allowances and Reserves, Charged to Cost and Expense		1.6	2.6	2.5
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	[1]	1.4	2.6	2.4
Valuation Allowances and Reserves, Ending Balance		$ 1.7	$ 1.5	$ 1.5

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