Accumulated Other Comprehensive Income (Loss) (Reclassification out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	$ 168.6	$ 165.9	$ 319.3	$ 322.4
Net sales	272.0	248.6	514.1	475.9
Interest expense	9.5	9.8	19.9	19.0
Total loss, before tax	(83.1)	(65.3)	(132.9)	(114.7)
Tax impact	19.4	17.7	32.8	25.9
Total loss, net of tax	(54.5)	(47.3)	(93.6)	(75.1)
Total reclassifications for the period	2.5	3.3	5.1	7.0
Derivative Gain (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period	0.3	0.3	0.8	1.2
Derivative Gain (Loss) [Member] | Reclassified From Accumulated Other Comprehensive (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total loss, before tax	0.4	0.4	1.0	1.6
Tax impact	(0.1)	(0.1)	(0.2)	(0.4)
Total loss, net of tax	0.3	0.3	0.8	1.2
Derivative Gain (Loss) [Member] | Natural Gas Commodity Contracts [Member] | Reclassified From Accumulated Other Comprehensive (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold				0.4
Derivative Gain (Loss) [Member] | Foreign Exchange Contracts - Purchases [Member] | Reclassified From Accumulated Other Comprehensive (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold				0.1
Derivative Gain (Loss) [Member] | Foreign Exchange Contracts - Sales [Member] | Reclassified From Accumulated Other Comprehensive (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net sales		0.1		0.3
Derivative Gain (Loss) [Member] | Interest Rate Swap Contracts [Member] | Reclassified From Accumulated Other Comprehensive (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest expense	0.4	0.3	1.0	0.8
Amortization Of Net Actuarial Loss [Member] | Reclassified From Accumulated Other Comprehensive (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amortization of net actuarial loss	2.7	3.7	5.4	7.3
Pension And Postretirement Adjustments [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period	2.2	3.0	4.3	5.8
Pension And Postretirement Adjustments [Member] | Reclassified From Accumulated Other Comprehensive (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total expense, before tax	2.7	3.7	5.4	7.3
Tax impact	(0.5)	(0.7)	(1.1)	(1.5)
Total expense, net of tax	$ 2.2	$ 3.0	$ 4.3	$ 5.8