Basis of Presentation - Trade Receivable, Net (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade receivables	$ 194.8	$ 176.4
Allowance for credit losses	(2.0)	(1.3)
Trade receivables, net	192.8	175.1
Trade receivables — billed
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade receivables	146.4	136.6
Trade receivables — unbilled
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade receivables	$ 48.4	$ 39.8