Shareholders' Equity (Reclassification out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	$ 569.8	$ 531.5	$ 499.1
Net sales	893.6	837.3	805.1
Interest expense	35.4	49.5	44.6
Total income from continuing operations, before tax	(222.1)	(150.6)	(94.6)
Tax impact	1.5	51.3	36.7
Total (loss) from discontinued operations, net of tax	65.8	(5.4)	(36.3)
Total income, net of tax	(154.8)	(104.7)	(94.2)
Selling, general and administrative expenses	135.7	155.5	180.8
Total expense from discontinued operations net of tax	4.2	(9.9)	$ (5.3)
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period	24.8	33.6
Derivative Adjustments [Member] | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total income from continuing operations, before tax	0.6	7.9
Tax impact	(0.2)	(2.8)
Total income from continuing operations, net of tax	0.4	5.1
Total (loss) from discontinued operations, net of tax		(0.6)
Total income, net of tax	0.4	4.5
Derivative Adjustments [Member] | Natural Gas Contracts [Member] | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	(0.3)	1.2
Derivative Adjustments [Member] | Foreign Exchange Contracts - Purchases [Member] | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	0.1	(0.2)
Derivative Adjustments [Member] | Foreign Exchange Contracts - Sales [Member] | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net sales	(0.1)	(1.4)
Derivative Adjustments [Member] | Interest Rate Swap Contracts [Member] | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest expense	0.9	8.3
Prior Service Cost Amortization [Member] | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	0.9	0.6
Selling, general and administrative expenses	0.6	0.6
Amortization Of Net Actuarial Loss [Member] | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	7.4	20.7
Selling, general and administrative expenses	7.8	18.4
Pension And Postretirement Adjustments [Member] | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total expense from continuing operations, before tax	37.5	40.3
Tax impact	(13.1)	(14.1)
Total expense from continuing operations, net of tax	24.4	26.2
Total expense from discontinued operations net of tax		2.9
Total expense, net of tax	24.4	$ 29.1
Partial Settlement [Member] | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	12.5
Selling, general and administrative expenses	$ 8.3