Contingent Liabilities (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2016
Commitments And Contingent Liabilities [Line Items]
Amount of bank guarantees and standby letters of credit issued by financial institutions		$ 4.8	$ 5.5
Undiscounted remediation liability associated with environmentally contaminated non-operating facility		7.2	8.5
ARGENTINA | Argentina Supreme Court [Member]
Commitments And Contingent Liabilities [Line Items]
Contingent tax liability		$ 0.6	$ 1.3	$ 8.7
Contingent tax liability, decrease	$ 4.5