Supplemental Balance Sheet Information - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Supplemental Balance Sheet Disclosures [Line Items]
Reserves and allowances	$ 0.3	$ 0.2
Decrease in accounts receivable	1.2
Cash advance for accounts receivable sold	$ 1.1
Repurchase of accounts receivable, term	5 months
Interest per month on receivables sold	2.00%
Other Current Liabilities
Supplemental Balance Sheet Disclosures [Line Items]
Deferred revenue	$ 7.0	6.7
Levy accruals	5.5	4.9
Accrued payroll	2.0	2.6
Other Liabilities
Supplemental Balance Sheet Disclosures [Line Items]
Pension liabilities	25.3	$ 24.1
Equity securities | Other Noncurrent Assets
Supplemental Balance Sheet Disclosures [Line Items]
Cost method investments	$ 4.0