Discontinued Operations (Details) € in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 EUR (€)	Oct. 31, 2015 USD ($)
Selected financial information for discontinued operations
Net curtailment gain related to divesture of pension plan			$ 15.8
Write-off of deferred actuarial loss			5.5
Selected cash flow information of discontinued operations
Depreciation and amortization	$ 0.0	$ 0.0	2.7
Lahnstein Mill
Discontinued Operations
Cash proceeds from sale of mill				€ 50	$ 5.4
Pension and related liabilities of discontinued operations			21.0
Asset impairment			12.0
Transaction costs			1.7
Selected financial information for discontinued operations
Net sales	0.0	0.0	43.2
Cost of products sold	0.0	0.0	39.7
Gross Profit	0.0	0.0	3.5
Selling, general and administrative expenses	0.0	0.0	3.5
Restructuring costs	0.0	0.0	0.1
Other income — net	0.0	0.0	(0.3)
Income (Loss) From Discontinued Operations Before Income Taxes	0.0	0.0	0.2
Loss on sale	0.0	(0.6)	(13.6)
Income (loss) before income taxes	0.0	(0.6)	(13.4)
Income tax provision (benefit)	0.0	(0.2)	(4.0)
Income (loss) from discontinued operations	0.0	(0.4)	(9.4)
Selected cash flow information of discontinued operations
Depreciation and amortization	0.0	0.0	2.7
Capital expenditures	$ 0.0	$ 0.0	$ 0.6